EPS@ISEP | The European Project Semester (EPS) at ISEP

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
report [2013/06/12 00:05] – [4.2 Materials.] team3report [2013/06/12 18:51] (current) – [Appendices] team3
Line 382: Line 382:
  
 === 2.5.2 Different types of data storage and their specifications === === 2.5.2 Different types of data storage and their specifications ===
-Secondary data can be stored in different ways. The most appropriate methods are:+Secondary storage can be realised in different ways. The most appropriate methods are:
  
   * __Hard Disk__   * __Hard Disk__
Line 426: Line 426:
 === 2.5.3 Conclusion === === 2.5.3 Conclusion ===
 We can conclude that for our application, a small, power efficient, and robust data storage unit is recommended. Therefore we have two options: a flash drive or a flash memory card. Our choice mainly depends on the dimensions and the weight. Due to their dimensions, their lower prices per storage capacity and the fact that they are reconfigurable (if you add more sensors, you can increase the data storage capacity) of flash memory cards, our final choice will be the use of a micro flash memory card (microSD, microSDHC or microSDXC).\\ We can conclude that for our application, a small, power efficient, and robust data storage unit is recommended. Therefore we have two options: a flash drive or a flash memory card. Our choice mainly depends on the dimensions and the weight. Due to their dimensions, their lower prices per storage capacity and the fact that they are reconfigurable (if you add more sensors, you can increase the data storage capacity) of flash memory cards, our final choice will be the use of a micro flash memory card (microSD, microSDHC or microSDXC).\\
-An important remark to make is the fact that a flash memory device only has a limited number of write and erase cycles before the drive or card fails. Due to this fact, we will have to replace the flash memory card after a while.+An important remark to make is the fact that a flash memory device only has a limited number of write and erase cycles before the drive or card fails. Due to this fact, we will have to replace the flash memory card after some time.
  
 ==== 2.6 Battery ==== ==== 2.6 Battery ====
Line 1117: Line 1117:
 === 6.2.1 Steel structure === === 6.2.1 Steel structure ===
 The fibreglass hull cannot constitute, from a structural point of view, the entire buoy. First of all, it does not provide enough space to attach all necessary components. Secondly, because of its geometry (many round surfaces) it would not be easy to connect to it, for example, the wind sensor. Moreover, the hull is not tall enough; the LED lamp would hardly be visible from a larger distance, and all components would be subject to a more frequent contact with water. Therefore, in order to have a functional buoy, there must be an external frame that holds onto the hull. This frame must fulfil a number of requirements. First of all, it must be made of a material resistant to the effects of saltwater and UV radiation. Secondly, it must provide enough space to attach the antennas, sensors, and lamp. Moreover, its geometry must ensure that the buoy is resistant to wind and waves.  Furthermore, it must be strong enough so that it does not break. \\ The fibreglass hull cannot constitute, from a structural point of view, the entire buoy. First of all, it does not provide enough space to attach all necessary components. Secondly, because of its geometry (many round surfaces) it would not be easy to connect to it, for example, the wind sensor. Moreover, the hull is not tall enough; the LED lamp would hardly be visible from a larger distance, and all components would be subject to a more frequent contact with water. Therefore, in order to have a functional buoy, there must be an external frame that holds onto the hull. This frame must fulfil a number of requirements. First of all, it must be made of a material resistant to the effects of saltwater and UV radiation. Secondly, it must provide enough space to attach the antennas, sensors, and lamp. Moreover, its geometry must ensure that the buoy is resistant to wind and waves.  Furthermore, it must be strong enough so that it does not break. \\
-The very first and general design of this frame consists of a stainless steel structure that clasps the hull all around its ring and protrudes upwards and downwards with four tubes. It consists of two vertically symmetrical parts that are put together with the use of bolts. In the upper part of the structure there is a horizontal platform for the box with the electronic equipment, and an additional place to attach the lamp and antennas. On the other hand, in the lower part there is a enough place to attach some sort of ballast and connect somehow an anchor. Figure 6 1 presents a drawing of this rough idea.+The very first and general design of this frame consists of a stainless steel structure that clasps the hull all around its ring and protrudes upwards and downwards with four tubes. It consists of two vertically symmetrical parts that are put together with the use of bolts. In the upper part of the structure there is a horizontal platform for the box with the electronic equipment, and an additional place to attach the lamp and antennas. On the other hand, in the lower part there is a enough place to attach some sort of ballast and connect somehow an anchor. Figure 6-1 presents a drawing of this rough idea.
  
 {{:figure_6-1.png?200|}}\\ {{:figure_6-1.png?200|}}\\
Line 1148: Line 1148:
 Figure 6-4 Final design** Figure 6-4 Final design**
  
-In essence, this design constitutes a mixture of all the three previous ones. However, before it has reached this final look, it underwent some smaller and bigger changes, especially in terms of the “fasteners” - circular tubes that connect the “holders” (pieces that directly embrace the hull’s ring).  The role of these fasteners is to prevent the structure from spreading apart to the sides under the force of weight of the structure itself and the components attached to it. In total there are six of them, three in the upper part and three in the lower. Just like in the second design, this structure is divided horizontally in the middle of the hull. These two parts are connected tightly to one another with the use of three bolts that go through three flat plates that protrude from the hull’s ring. In the upper part of the structure there is a horizontal, circular plate to which the wind sensor, lamp and antennas can be attached. In the lower part, on the other hand, there is a similar plate, but of a greater diameter so as to provide the space required for the CTD sensor. At the very bottom we see a cylindrical rod for the placement of circular weights (Figure 6 5) as the ballast. Because these weights can have a mass ranging from as small as 0,5 kg to as big as 20 kg, they can be easily arranged in such a way as to obtain a desired total weight accordingly to the existing needs.+In essence, this design constitutes a mixture of all the three previous ones. However, before it has reached this final look, it underwent some smaller and bigger changes, especially in terms of the “fasteners” - circular tubes that connect the “holders” (pieces that directly embrace the hull’s ring).  The role of these fasteners is to prevent the structure from spreading apart to the sides under the force of weight of the structure itself and the components attached to it. In total there are six of them, three in the upper part and three in the lower. Just like in the second design, this structure is divided horizontally in the middle of the hull. These two parts are connected tightly to one another with the use of three bolts that go through three flat plates that protrude from the hull’s ring. In the upper part of the structure there is a horizontal, circular plate to which the wind sensor, lamp and antennas can be attached. In the lower part, on the other hand, there is a similar plate, but of a greater diameter so as to provide the space required for the CTD sensor. At the very bottom we see a cylindrical rod for the placement of circular weights (Figure 6-5) as the ballast. Because these weights can have a mass ranging from as small as 0,5 kg to as big as 20 kg, they can be easily arranged in such a way as to obtain a desired total weight accordingly to the existing needs.
  
 {{:figure_6-5.png?200|}}\\ {{:figure_6-5.png?200|}}\\
Line 1157: Line 1157:
  
 === 6.2.2 Mooring === === 6.2.2 Mooring ===
-In order to make sure that the buoy stays in one place on a river, it needs to be connected to an anchor. However, the anchor is only a part of the overall system that is required for the buoy. This system consists of: one anchor, two swivels, one shackle, one thimble, one nylon rope, one chain, and one eye bolt. The order in which all of these parts are connected is presented in Figure 6 6. First there is an anchor which lies on the bottom of the river. The next part is a strong swivel that is attached to the anchor on one end and to a chain on the other. The chain’s other end is connected to the rope with a shackle that goes through the rope’s thimble. The rope then goes up until it reaches the other swivel where it goes through a thimble. The rope is fastened with two stainless steel clamps. The swivel’s other end is connected to the eye bolt that is screwed into the threaded hole in the steel structure.+In order to make sure that the buoy stays in one place on a river, it needs to be connected to an anchor. However, the anchor is only a part of the overall system that is required for the buoy. This system consists of: one anchor, two swivels, one shackle, one thimble, one nylon rope, one chain, and one eye bolt. The order in which all of these parts are connected is presented in Figure 6-6. First there is an anchor which lies on the bottom of the river. The next part is a strong swivel that is attached to the anchor on one end and to a chain on the other. The chain’s other end is connected to the rope with a shackle that goes through the rope’s thimble. The rope then goes up until it reaches the other swivel where it goes through a thimble. The rope is fastened with two stainless steel clamps. The swivel’s other end is connected to the eye bolt that is screwed into the threaded hole in the steel structure.
  
 {{:figure_6-6.png?200|}}\\ {{:figure_6-6.png?200|}}\\
Line 1163: Line 1163:
 ** **
  
-The cylindrical rod has an additional small hole, as seen in Figure 6 7. Its role is to provide the possibility of introducing a “blocker” – a sort of small cylinder. Once the eye bolt is screwed into the threaded hole, it is necessary to drill in it a small groove in the place of the small hole in the cylindrical rod. After this, it is possible to place the blocker in place so that part of it enters the groove, and part stays in the hole in the wall of the cylindrical rod. The remaining space inside the whole can be filled with some material to prevent corrosion.+The cylindrical rod has an additional small hole, as seen in Figure 6-7. Its role is to provide the possibility of introducing a “blocker” – a sort of small cylinder. Once the eye bolt is screwed into the threaded hole, it is necessary to drill in it a small groove in the place of the small hole in the cylindrical rod. After this, it is possible to place the blocker in place so that part of it enters the groove, and part stays in the hole in the wall of the cylindrical rod. The remaining space inside the whole can be filled with some material to prevent corrosion.
  
 {{:figure_6-7.png?200|}}\\ {{:figure_6-7.png?200|}}\\
Line 1182: Line 1182:
 The buoy will be submerged for a volume of 0,0565 m³ (an important remark that we have to make is that we do not have the original drawings of the fibreglass hull. Therefore we have to assume that the submerged volume is a perfect hemisphere and we have to rely on the measurement of the radius: r = 0,3 m). The buoy will be submerged for a volume of 0,0565 m³ (an important remark that we have to make is that we do not have the original drawings of the fibreglass hull. Therefore we have to assume that the submerged volume is a perfect hemisphere and we have to rely on the measurement of the radius: r = 0,3 m).
  
-The force of buoyancy can be calculated with the law of Archimedes: +The force of buoyancy can be calculated with the law of Archimedes: \\ 
-{{:x2.png?200|}}\\+{{:x2.png|}}\\
 At the end, the overall weight of the electronic buoy has to be lower than the force of buoyancy (= 554,27 N). The overall mass that can be attached on the fibreglass hull can be calculated on the following manner: At the end, the overall weight of the electronic buoy has to be lower than the force of buoyancy (= 554,27 N). The overall mass that can be attached on the fibreglass hull can be calculated on the following manner:
  
-{{:x3.png?200|}}\\+{{:x3.png|}}\\
 Another calculation can be made for the ultimate maximum mass that can be attached to the fibreglass hull. In this case the buoy will be submerged until half of the “Saturn-ring” is underneath the water surface, like shown in Figure 6-9: Another calculation can be made for the ultimate maximum mass that can be attached to the fibreglass hull. In this case the buoy will be submerged until half of the “Saturn-ring” is underneath the water surface, like shown in Figure 6-9:
  
Line 1192: Line 1192:
 **Figure 6-9 Buoyancy force (83,3kg)** **Figure 6-9 Buoyancy force (83,3kg)**
  
-The volume underneath the water can be calculated by adding the volume of the cylinder to the volume we calculated above: +The volume underneath the water can be calculated by adding the volume of the cylinder to the volume we calculated above:\\ 
-{{:x4.png?200|}}\\ +{{:x4.png?|}}\\ 
-The corresponding force of buoyancy now can be calculated: +The corresponding force of buoyancy now can be calculated:\\ 
-{{:x5.png?200|}}\\+{{:x5.png?|}}\\
 The overall mass that can be attached on the fibreglass hull can be calculated on the following manner:\\ The overall mass that can be attached on the fibreglass hull can be calculated on the following manner:\\
-{{:x6.png?200|}}\\+{{:x6.png?|}}\\
 We can conclude out these calculations that, in the first case (Figure 6-8) a mass of 56,50 kg can be placed in the water. The weight of the fibreglass hull is 16,50 kg, so 40,00 kg can be attached to the hull. An additional 31,00 kg can be added until the ultimate mass is reached, as shown in Figure 6-9. We can conclude out these calculations that, in the first case (Figure 6-8) a mass of 56,50 kg can be placed in the water. The weight of the fibreglass hull is 16,50 kg, so 40,00 kg can be attached to the hull. An additional 31,00 kg can be added until the ultimate mass is reached, as shown in Figure 6-9.
  
Line 1207: Line 1207:
 *An important remark to make is the fact that in this test the weight of the fibreglass hull has to be included. We placed the hull in the water were it will cause a force on the surface; then we added water into the hull to enlarge this force. 16,50 kg has to be added to the 2 results. *An important remark to make is the fact that in this test the weight of the fibreglass hull has to be included. We placed the hull in the water were it will cause a force on the surface; then we added water into the hull to enlarge this force. 16,50 kg has to be added to the 2 results.
  
-Because the results of the practical test differ from the results of the calculations, we can conclude that the shape of the hull is not a perfect hemisphere, it is bigger. Because we want to obtain the highest safety level as possible, we will make further calculations with the lowest masses: 56,00 kg and 88,30 kg.+Because the results of the practical test differ from the results of the calculations, we can conclude that the shape of the hull is not a perfect hemisphere, it is bigger. Because we want to obtain the highest safety level as possible, we will make further calculations with the lowest masses: 56,50 kg and 88,30 kg.
  
 Now we calculated the ultimate maximum mass that can be attached to the fibreglass hull, we will take a look to the loads: Now we calculated the ultimate maximum mass that can be attached to the fibreglass hull, we will take a look to the loads:
Line 1214: Line 1214:
 {{:table_6-4.png?200|}} {{:table_6-4.png?200|}}
  
-The total mass of the loads, placed in the water, will be 44,20 kg. These loads will cause a force equal to: +The total mass of the loads, placed in the water, will be 44,20 kg. These loads will cause a force equal to:\\ 
- +{{:x7.png?|}}\\ 
-{{:x7.png?200|}}\\ +Out these calculations we can conclude that the buoy will be buoyant and that we can add an additional ballast with a mass of 12,30 kg. If we add this ballast, the fibreglass hull will be submerged until the water level is exactly underneath the ”Saturn-ring”. 
- +
-Out these calculations we can conclude that the buoy will be buoyant and that we can add an additional ballast with a mass of 11,80 kg. If we add this ballast, the fibreglass hull will be submerged until the water level is exactly underneath the ”Saturn-ring”. +
  
 Another important factor of the buoyancy is the stability. An object can be buoyant, but if it is not stable it can turn over. A floating object is stable if it tends to restore itself to an equilibrium position after a small displacement. For example, floating objects will generally have vertical stability, as if the object is pushed down slightly, this will create a greater buoyancy force, which, unbalanced by the weight force, will push the object back up. Rotational stability is of great importance to floating vessels. Given a small angular displacement, for instance due to a wave, the vessel may return to its original position (stable), move away from its original position (unstable), or remain where it is (neutral). \\ Another important factor of the buoyancy is the stability. An object can be buoyant, but if it is not stable it can turn over. A floating object is stable if it tends to restore itself to an equilibrium position after a small displacement. For example, floating objects will generally have vertical stability, as if the object is pushed down slightly, this will create a greater buoyancy force, which, unbalanced by the weight force, will push the object back up. Rotational stability is of great importance to floating vessels. Given a small angular displacement, for instance due to a wave, the vessel may return to its original position (stable), move away from its original position (unstable), or remain where it is (neutral). \\
Line 1235: Line 1233:
 **Figure 6-11 Centre of buoyancy (56,5kg)** **Figure 6-11 Centre of buoyancy (56,5kg)**
  
-The symmetric stainless steel structure will clasp around the ”Saturn-ring”, so we can safely say that 3/8 of the mass of stainless steel is underneath the centre of buoyancy. Also the CTD, 1/4 of the fibreglass hull and the ballast will be under the centre of buoyancy.\\+The batteries and the case with the electronics will be situated around the point of buoyancy, therefore they can be neglected. The symmetric stainless steel structure will clasp around the ”Saturn-ring”, so we can safely say that 3/8 of the mass of stainless steel is underneath the centre of buoyancy. Also the CTD, 1/4 of the fibreglass hull and the ballast will be under the centre of buoyancy.\\
  
 **Table 6-5 Mass above the centre of buoyancy**\\ **Table 6-5 Mass above the centre of buoyancy**\\
Line 1244: Line 1242:
  
 **Table 6-6 Mass under the centre of buoyancy**\\ **Table 6-6 Mass under the centre of buoyancy**\\
-{{:table_6-6.png?200|}}+{{:table_6-6.png?200|}}\\
  
-We can conclude that, when we add a ballast of 11,80 kg, the point of gravity will be at the same height as the point of buoyancy, whereby we can say that the prototype will not be stable.+We can conclude that, when we add a ballast of 12,30 kg, the point of gravity will be at the same height as the point of buoyancy, whereby we can say that the prototype will not be stable.
  
 A solution for this problem is to add more ballast. When we add more ballast the fibreglass hull will submerge deeper. We can keep adding ballast until the water level is in the middle of the ”Saturn-ring” (the maximum mass we can add is 44,10 kg). The perfect balance between ballast and the depth of the buoy has to be determined with further tests. A solution for this problem is to add more ballast. When we add more ballast the fibreglass hull will submerge deeper. We can keep adding ballast until the water level is in the middle of the ”Saturn-ring” (the maximum mass we can add is 44,10 kg). The perfect balance between ballast and the depth of the buoy has to be determined with further tests.
  
 === 6.2.4 Water-resistance of the hull === === 6.2.4 Water-resistance of the hull ===
-The electronics will be placed in the interior. Therefore it is necessary to provide a waterproof environment. After recognising the imperfect condition of the existing rubber-tape at the clasp and the fact that the lid is not perfectly sealing, we started thinking of other possibilities to make the hull water-resistant. In addition, from day one the bolted connections were not waterproof and some threads were loose. In collaboration with “ALTO – Perfis Pultrudidos, Lda.” (ALTO Contact) or more precise, Mr. Mario Alvim, we discussed different solutions. +The electronics will be placed in the interior. Therefore it is necessary to provide a waterproof environment. After recognising the imperfect condition of the existing rubber-tape at the clasp and the fact that the lid is not perfectly sealed, we started thinking of other possibilities to make the hull water-resistant. In addition, from day one the bolted connections were not waterproof and some threads were loose. In collaboration with “ALTO – Perfis Pultrudidos, Lda.” (ALTO Contact) or more precise, Mr. Mario Alvim, we discussed different solutions. 
  
 {{:pd_6.2.3_figure_x-1_plastic_cover.png?200|}}\\ {{:pd_6.2.3_figure_x-1_plastic_cover.png?200|}}\\
Line 1281: Line 1279:
  
  
-=== 6.2.5 Lay out and guarantee of the electronic components in the inside ===+=== 6.2.5 Layout of the electronic components in the inside ===
  
 As mentioned above, batteries as well as all electronics like microcontroller, Wi-Fi module or GPS will be placed as low as possible in the interior of the hull. In order to protect them we came up with different ideas to ensure the safety of the components right from the start. One of the first ideas is shown in Figure 6-17. For a different project at “LSA” a self-made acrylic glass box protects the electronic components. The top of the box is detachable and a rubber layer between the lid and the main box provides a waterproof connection, if screws close it. As mentioned above, batteries as well as all electronics like microcontroller, Wi-Fi module or GPS will be placed as low as possible in the interior of the hull. In order to protect them we came up with different ideas to ensure the safety of the components right from the start. One of the first ideas is shown in Figure 6-17. For a different project at “LSA” a self-made acrylic glass box protects the electronic components. The top of the box is detachable and a rubber layer between the lid and the main box provides a waterproof connection, if screws close it.
Line 1319: Line 1317:
 **Figure 6-22 Template of the container in the extra tier** **Figure 6-22 Template of the container in the extra tier**
  
-For checking the space inside the boxes and comparing it with the necessary components, we draw template and placed microcontroller, SD-socket and GNSS module in there. As can be seen in Figure 6- 23, the box has still enough space for an additional microcontroller as well as the WiFi module.+For checking the space inside the boxes and comparing it with the necessary components, we draw template and placed microcontroller, SD-socket and GNSS module in there. As can be seen in Figure 6-23, the box has still enough space for an additional microcontroller as well as for the Wi-Fi module.
  
 {{:pd_6.2.4_figure_x-12_template_with_electronics.png?200|}}\\ {{:pd_6.2.4_figure_x-12_template_with_electronics.png?200|}}\\
Line 1331: Line 1329:
 **Figure 6-24 Electronics architecture** **Figure 6-24 Electronics architecture**
  
-The first general concept was to create several different parts responsible for different tasks, such as: underwater measurements, on-surface measurements, data storage and transferring, and power supply. We started to improve and expand that idea what led us to the final solution of the electronic architecture shown in Figure 6-24. +The first general concept was to create several different parts responsible for different tasks, such as: underwater measurements, on-surface measurements, data storage and transferring, and power supply. We started to improve and expand that idea what led us to the final solution of the electronic architecture shown in Figure 6-24. \\
 On the top of the buoy, there will be a GNSS receiver (to define buoy location and synchronise actual time), place for a solar panel, blinking lamp and, the most important, a platform for sensors to measure conditions above the water surface (A). Data from these sensors will be sent via standard interfaces to the control unit (E). There will be also a second platform for sensors needed to be placed under water (B). All data will be collected in a data storage device (C) and then sent to the user using an antenna connected with wireless communication unit (D). The antenna might be placed either on the top or inside the hull which depends on needed signal strenght. Every component that needs electric energy will be supplied by rechargeable battery (F) which will be able to be connected to a solar panel in the future. Components C, D, E, and F (the grey area) will be placed inside the fibreglass hull and protected against water. On the top of the buoy, there will be a GNSS receiver (to define buoy location and synchronise actual time), place for a solar panel, blinking lamp and, the most important, a platform for sensors to measure conditions above the water surface (A). Data from these sensors will be sent via standard interfaces to the control unit (E). There will be also a second platform for sensors needed to be placed under water (B). All data will be collected in a data storage device (C) and then sent to the user using an antenna connected with wireless communication unit (D). The antenna might be placed either on the top or inside the hull which depends on needed signal strenght. Every component that needs electric energy will be supplied by rechargeable battery (F) which will be able to be connected to a solar panel in the future. Components C, D, E, and F (the grey area) will be placed inside the fibreglass hull and protected against water.
  
Line 1346: Line 1344:
 **Figure 6-26 Final signal schematic** **Figure 6-26 Final signal schematic**
  
 +The STM32F3 Discovery board supports many interfaces, but 2 of them (SPI and I2C) are already used for built-in peripherals (Gyroscope and E-compass). One SPI is used to connect a microSD card socket and the last one can be used to attach an additional sensor. Unfortunately, according to the MCU datasheet [57], all 3 SPIs cannot be used simultaneously with all USARTs and UARTs (which are necessary for RS232 connection). This is why only 3 RS232 can be mounted. Also the Wi-Fi module needs an UART interface what reduces the number of RS232 to 2. Wi-Fi however is supposed to be connected to the slave MCU only temporarily for tests. For the future development, when an appropriate master MCU has to be chosen, the Wi-Fi module can be removed from the slave. Why is there no master MCU included in this solution? This is because the master MCU has to be a proper controller, containing an operating system to manage complex functions. Choosing  one, would be too time consuming for this project.
  
-STM32F3 Discovery board supports many interfaces but 2 of them (SPI and I2C) are already used for built-in peripherals (Gyroscope and E-compass). One SPI is used to connect a microSD card socket and the last one can be used to attach additional sensor. Unfortunately, according to MCU datasheet [57], all 3 SPIs cannot be used simultaneously with all USARTs and UARTs (which are necessary for RS232 connection). This is why only 3 RS232 can be mounted. Also Wi-Fi module needs UART interface what reduces number of RS232 to 2. Wi-Fi however is supposed to be connected to the slave MCU only temporarily for tests. For the future development, when appropriate master MCU has to be chosen, Wi-Fi module can be removed from the slave. Why is there no master MCU included in this solution? This is because it has to be proper controller containing operating system to manage complex functions, choosing which is too time consuming for this project.\\ +The schematic presented on Figure 6 26 contains only data transferring lines, no electric lines are included there. Finally, the following interfaces are available: 3x RS232 (or 2, which depends on Wi-Fi) from which one is used for the CTD sensor; 1x CAN; 1x SPI; 1x RJ-11 which is used for the wind sensor; 1x USB which can be used either for a connection with the second controller in the future or as a free connector for any other device or sensor.
-Schematic presented on Figure 6-26 contains only data transferring lines, no electric lines are included there. Finally, the following interfaces are available: 3x RS232 (or 2, which depends on Wi-Fi) from which one is used for CTD sensor; 1x CAN; 1x SPI; 1x RJ-11 which is used for wind sensor; 1x USB which can be used either for connection with second controller in the future or as an free connector for any other device or sensor.\\+
  
 === 6.3.3 Power supply === === 6.3.3 Power supply ===
Line 1356: Line 1354:
   * 5V    - e.g. STM32F3 Discovery board,\\   * 5V    - e.g. STM32F3 Discovery board,\\
   * 3.3V  - e.g. microSD card socket, wind sensor.\\   * 3.3V  - e.g. microSD card socket, wind sensor.\\
-The first solution was to use a 12V battery supply as these batteries are very popular and easy to find. With that approach we would be able to power, for instance, a CTD sensor directly from the battery and we would need 2 voltage regulators to power 5V and 3.3V operating devices. In this case the energy losses spent on voltage conversion would be big because the voltage difference is at least 7V. This is why, after consultation with the supervisors, we decided to use 6V batteries. The voltage can be then converted from 6V to 5 and 3.3V what reduces the energy losses. However, the 12V supply is still needed. This can be resolved in 2 ways: 6V to 12V regulator may be used or additional 12V battery may be applied. We decided, for the best power efficiency, to use additional 12V battery (or serial connection of 2 6V batteries, which have to be used anyway). Finally, powering all components will be realized as it is shown on Figure 6-27.+The first solution was to use a 12V battery supply as these batteries are very popular and easy to find. With that approach we would be able to power, for instance, a CTD sensor directly from the battery and we would need 2 voltage regulators to power 5V and 3.3V operating devices. In this case the energy losses spent on voltage conversion would be big because the voltage difference is at least 7V. This is why, after consultation with the supervisors, we decided to use 6V batteries. The voltage can be then converted from 6V to 5 and 3.3V what reduces the energy losses. However, the 12V supply is still needed. This can be resolved in 2 ways: 6V to 12V regulator may be used or additional 12V battery may be applied. We decided, for the best power efficiency, to use additional 12V battery (or serial connection of 2 6V batteries, which have to be used anyway). Finally, powering all components will be realised as it is shown on Figure 6-27.
  
 {{:figure_6-27.png?200|}}\\ {{:figure_6-27.png?200|}}\\
Line 1362: Line 1360:
  
 Devices needed to be powered are gathered in the Table 6-8. Devices needed to be powered are gathered in the Table 6-8.
 +
 +**Table 6-8 Devices needed to be powered**
  
 {{:table_6-8.png?200|}} \\ {{:table_6-8.png?200|}} \\
-**Table 6-8 Devices needed to be powered**  
  
-Each component has to be grounded to the common ground. Besides the powering wires of currently chosen components, there should be possibility of easily attaching voltage lines into not used interfaces, in order to provide voltage to sensors to be added in the future. This can be done by attaching parallel wires to already existing ones. Exemplary voltage lines are presented on Figure 6-27.\\ +Each component has to be grounded to the common ground. Besides the powering wires of currently chosen components, there should be a possibility of easily attaching voltage lines into not used interfaces, in order to provide voltage to sensors to be added in the future. This can be done by attaching parallel wires to already existing ones. Exemplary voltage lines are presented on Figure 6-27. 
-To convert the voltage to needed levels we use linear regulators due to low price and availability at ISEP. \\ +To convert the voltage to needed levels we use linear regulators due to low price and availability at ISEP. 
-As it can be seen at the schematic, there are components named MAX232. These are voltage level converters. They change TTL standard level (used by output signals of almost every microcontroller) into RS232 standard level which uses wider voltage range. MAX232 converters also need external power supply.\\+As it can be seen at the schematic, there are components named MAX232. These are voltage level converters. They change TTL standard level (used by output signals of almost every microcontroller) into RS232 standard level which uses wider voltage range. MAX232 converters also need external power supply.
  
-In order to know the number of batteries needed for the system to be autonomous (for some period of time), power calculations had to be done. First, we calculated current and power consumption of each component. Sometimes each of these two values was given in device's datasheet, sometimes only one. If so, the second value could have been easily calculated from the following very simple formula:\\+In order to know the number of batteries needed for the system to be autonomous (for some period of time), power calculations had to be done. First, we calculated current and power consumption of each component. Sometimes each of these two values was given in device's datasheet, sometimes only one. If so, the second value could have been easily calculated from the following very simple formula:
  
 {{:bildschirmfoto_2013-06-11_um_14.54.38.png?200|//}}\\ {{:bildschirmfoto_2013-06-11_um_14.54.38.png?200|//}}\\
Line 1379: Line 1378:
 Secondly, we simply added each power consumption value to get the overall value. Results are presented in Table 6-9: Secondly, we simply added each power consumption value to get the overall value. Results are presented in Table 6-9:
  
-{{:table_6-9.png?200|}}\\ 
 **Table 6-9 Power calculation for used devices** **Table 6-9 Power calculation for used devices**
 +
 +{{:table_6-9.png?200|}}\\
  
 To estimate power demand of the whole system, also power dissipation of voltage regulators has to be taken into consideration. To calculate it, the following equation can be used: To estimate power demand of the whole system, also power dissipation of voltage regulators has to be taken into consideration. To calculate it, the following equation can be used:
  
-{{:bildschirmfoto_2013-06-11_um_14.51.51.png?200|}}\\+{{::power_dissipation.png|}}\\
 where\\ where\\
-Pd - power dissipated [W],\\ +P<sub>d</sub> - power dissipated [W],\\ 
-Uout - output voltage [V],\\ +U<sub>out</sub> - output voltage [V],\\ 
-Uin - input voltage [V].\\ +U<sub>in</sub> - input voltage [V].\\ 
-Iload - load current [mA].\\+I<sub>load</sub> - load current [mA].\\
  
 Power losses of voltage regulators are shown in  Power losses of voltage regulators are shown in 
 Table 6-10. Table 6-10.
  
-{{:table_6-10.png?200|}}\\ 
 **Table 6-10 Power dissipation in voltage regulators** **Table 6-10 Power dissipation in voltage regulators**
 +
 +{{:table_6-10.png?200|}}\\
  
 Comparing to power consumption of all other devices, power losses in regulators are significant. Dissipated power is equal to 13% of power needed for devices work. Comparing to power consumption of all other devices, power losses in regulators are significant. Dissipated power is equal to 13% of power needed for devices work.
Line 1411: Line 1412:
 === 6.3.4 Physical implementation === === 6.3.4 Physical implementation ===
  
-All electronic devices, except the CTD, blinking lamp, wind sensor and antennas, will be placed inside the white fibreglass hull. To make sure they will be protected against water, they can be put inside a small waterproof box (what was broadly described in section 6.2.4 Water-resistance of the hull). On the top of the box there will be two wholes: one for power wiring, second for signal wiring. Wires will be put together into a bigger cable which reduces number of needed wholes/connectors and protects them against water. One of these cables will go from an electronic box into a battery box and will contain three wires: 3.3V line, 5V line, GND line. In this case, to make the battery box easily removable form the hull, the cable has to be connected via waterproof connector, such as Bulgin [108]. Second of these cables will go from a battery box up to the interface panel on the upper side of the hull and will contain four wires: 3.3V line, 5V line, 12V line, GND line. It also has to be easily removable so the use of Bulgin connector is necessary. The last (third) cable will be linked between electronics box and interface panel. This one does not have to be easily removable (so use of special connector is not needed) but it has to be thick enough to collect at least 15 wires sending signals to all interfaces. \\+All electronic devices, except the CTD, blinking lamp, wind sensor and antennas, will be placed inside the white fibreglass hull. To make sure they will be protected against water, they can be put inside a small waterproof box (what was broadly described in section 6.2.4 Water-resistance of the hull). On the top of the box there will be two wholes: one for power wiring, second for signal wiring. Wires will be put together into a bigger cable which reduces number of needed wholes/connectors and protects them against water. One of these cables will go from an electronic box into a battery box and will contain three wires: 3.3V line, 5V line, GND line. In this case, to make the battery box easily removable form the hull, the cable has to be connected via waterproof connector, such as Bulgin [108]. The second of these cables will go from a battery box up to the interface panel on the upper side of the hull and will contain four wires: 3.3V line, 5V line, 12V line, GND line. It also has to be easily removable so the use of Bulgin connector is necessary. The last (third) cable will be linked between electronics box and interface panel. This one does not have to be easily removable (so use of special connector is not needed) but it has to be thick enough to collect at least 15 wires sending signals to all interfaces.  
 + 
 The idea of having an interface panel on the hull is to make the buoy more reconfigurable. The panel will have all interfaces connectors (all of them waterproof) which are for this moment: 3x RS232, 1x CAN, 1x SPI, 1x USB, 1x RJ-11 (or equivalent pin-numbered connector), 1x MCX, 1x SMA. If any new sensor is needed to attach, the white hull does not have to be opened. The layout of this system is simply presented on Figure 6-28. The idea of having an interface panel on the hull is to make the buoy more reconfigurable. The panel will have all interfaces connectors (all of them waterproof) which are for this moment: 3x RS232, 1x CAN, 1x SPI, 1x USB, 1x RJ-11 (or equivalent pin-numbered connector), 1x MCX, 1x SMA. If any new sensor is needed to attach, the white hull does not have to be opened. The layout of this system is simply presented on Figure 6-28.
 +
  
 {{:figure_6-28.png?200|}}\\  {{:figure_6-28.png?200|}}\\ 
Line 1435: Line 1438:
 The GNSS sensor will be used for measuring the current location and adding a timestamp to the data. The sensor provides different types of data. For us the $GPGGA is the most important format: The GNSS sensor will be used for measuring the current location and adding a timestamp to the data. The sensor provides different types of data. For us the $GPGGA is the most important format:
  
-{{:gnss_sensor.png?200|}}\\+{{:gnss_sensor.png?|}}\\
  
 1 = UTC of Position \\ 1 = UTC of Position \\
Line 1459: Line 1462:
 The CTD sensor will send data about conductivity, temperature and pressure (as a result of p = p0 + r x g x h) at intervals of 100 ms using the following format: The CTD sensor will send data about conductivity, temperature and pressure (as a result of p = p0 + r x g x h) at intervals of 100 ms using the following format:
  
-{{:ctd.png?200|}} \\+{{:ctd.png?300|}} \\
  
 1  = Id of the card \\ 1  = Id of the card \\
Line 1470: Line 1473:
 In this case average values need to be calculated because of the data transfer rate of 10 measurements each second. This is possible by integrating an “average filter” in the programming: In this case average values need to be calculated because of the data transfer rate of 10 measurements each second. This is possible by integrating an “average filter” in the programming:
  
-{{:programming.png?200|}}\\+{{:programming.png?300|}}\\
  
   * Wind sensor   * Wind sensor
Line 1523: Line 1526:
  
 {{:figure_6-33.png?200|}} {{:figure_6-33.png?200|}}
 +
 ** Figure 6-33 Flowchart of the programming**\\ ** Figure 6-33 Flowchart of the programming**\\
  
Line 1529: Line 1533:
 The overall structure of the program we will try to run on the microcontroller will contain the following parts: The overall structure of the program we will try to run on the microcontroller will contain the following parts:
  
-{{:1..png?200|}}\\ +{{::overall_structure.png?|}}
-{{:2..png?200|}}\\ +
-{{:3..png?200|}}\\ +
-{{:4..png?200|}}\\ +
-{{:4._2.png?200|}} \\ +
  
 In part 1 we declare the variables we need to use. For instance, a string called  “gnss” to store the collected data from the GNSS module, the pins we need to apply to connect the SD socket with the microcontroller, and a boolean variable “work” to check if the program is running fluently. In part 2 we will run the setup of the connection between GNSS module, CTD, wind sensor, SD socket, and the microcontroller. Here we will declare that the boolean “work” is true. The third part is the actual loop that the microcontroller is going to run. It will read data from the sensors, write it to the SD card, and  wait one second, while the boolean “work” is true. The fourth part is the development of the sub programs. The program read_data() will read data from the sensors and put it in to the corresponding string. For instance, read_gnss() will read the data from the GNSS sensor and store it in the corresponding string “gnss”. write_data will write to the SD card, e.g. write_gnss() will write the string “gnss” to the SD card.   In part 1 we declare the variables we need to use. For instance, a string called  “gnss” to store the collected data from the GNSS module, the pins we need to apply to connect the SD socket with the microcontroller, and a boolean variable “work” to check if the program is running fluently. In part 2 we will run the setup of the connection between GNSS module, CTD, wind sensor, SD socket, and the microcontroller. Here we will declare that the boolean “work” is true. The third part is the actual loop that the microcontroller is going to run. It will read data from the sensors, write it to the SD card, and  wait one second, while the boolean “work” is true. The fourth part is the development of the sub programs. The program read_data() will read data from the sensors and put it in to the corresponding string. For instance, read_gnss() will read the data from the GNSS sensor and store it in the corresponding string “gnss”. write_data will write to the SD card, e.g. write_gnss() will write the string “gnss” to the SD card.  
Line 1616: Line 1615:
  
 === 6.5.2 Planning ===  === 6.5.2 Planning === 
-At the beginning we started brainstorming. Focussing at the topic we did research regarding the project. In addition our client, “LSA”, expected us to develop a “storyboard” (Figure 6-41) which were supposed to have all types of necessary functions included. Because of the “storyboard”, it was possible to expand the former research as well as make them more specific. We used the elaborated information to allocate all possible tasks to single team members (Table 6-11). This task-allocation offered an overview but also helped every single team member for organising himself:+At the beginning we started brainstorming. Focussing at the topic we did research regarding the project. In addition our client, “LSA”, expected us to develop a “storyboard” (Figure 6-41) which was supposed to have all types of necessary functions included. Because of the “storyboard”, it was possible to expand the former researches as well as make them more specific. We used the elaborated information to allocate all possible tasks to a single team members (Table 6-11). This task-allocation offered an overview but also helped every single team member for organising himself:
  
-{{:figure_6-41.png?200|}}\\+{{:figure_6-41.png?|}}\\
 **Figure 6-41 Storyboard "regatta function"** **Figure 6-41 Storyboard "regatta function"**
  
Line 1624: Line 1623:
 {{:table_6-11.png?200|}}\\ {{:table_6-11.png?200|}}\\
  
-Based upon these facts and the given deadlines we created a “Gantt Chart”. As can be seen in Figure 6 42, the “Gantt” gives an overview on set milestones and linked activities/tasks which were supposed to be finished at specific dates. Specific dates were for example the “Interim Report Presentation”.\\ +Based upon these facts and the given deadlines we created a “Gantt Chart”. As can be seen in Figure 6-42, the “Gantt” gives an overview on set milestones and linked activities/tasks which were supposed to be finished at specific dates. Specific dates were for example the “Interim Report Presentation”.\\ 
-Creating the “Gantt Chart” at the beginning of a project may include changes during the project period. Because of missing experience, minor changes in our ´Gantt Chart´ had to be made. Some tasks needed more time, than expected. Also, tasks were more intensive than other ones.+Once created, “Gantt Chart” may be modified and updated during the project period. Because of missing experience, minor changes in our ´Gantt Chart´ had to be made. Some tasks needed more time, than expected. Also, some of them were more intensive than the other ones.
  
-In Figure 6 42 the final Gantt-chart of team three shown:\\+In Figure 6-42 the final Gantt-chart of team 3 is shown:\\
  
 {{:gantt_final_version_autonomous_bouy.png?200|}} \\ {{:gantt_final_version_autonomous_bouy.png?200|}} \\
-**Figure 6-42 Final gantt-chart team three**+**Figure 6-42 Final gantt-chart team 3**
  
 For more detailed planning we also used the “Scrum” model. For a two-week-period we developed “Sprints” which included specific, single tasks that were supposed to be easily handled by one team member. As a matter of fact, also during the single “Sprints” some activities were more intensive than others. Therefore, sometimes two members of the group were dedicated to one task. The model itself offers a perfect overview for all single tasks (Figure 6-43). For more detailed planning we also used the “Scrum” model. For a two-week-period we developed “Sprints” which included specific, single tasks that were supposed to be easily handled by one team member. As a matter of fact, also during the single “Sprints” some activities were more intensive than others. Therefore, sometimes two members of the group were dedicated to one task. The model itself offers a perfect overview for all single tasks (Figure 6-43).
Line 1650: Line 1649:
  
 ==== 7.1 Discussion ==== ==== 7.1 Discussion ====
-This project has proven to be exactly what we thought it would be: difficult and complex, yet interesting and educationally valuable. Before we even started the actual work, we first needed to learn a considerable amount about different types of buoys - what they consist of, and how they perform their functions. It took us quite a lot of time, but it allowed us to have a better view on how to get started and then proceed with further work. There were many things we needed to consider, discuss and decide on. This included, for example, the anchor, lamp, and microcontroller. The two tasks that took up a considerable amount of time and effort were the structure and programming. At this point we regret that we did not have more experience in these fields before beginning the project; perhaps then we could achieve more and with a better quality. Nevertheless, as a result of working on this project, we have all broadened our knowledge in many different ways: we know a lot about buoys, sensors, anchors, buoyancy etc.  In a general view, we believe the project was a success. First of all, we have managed to design and acquire the steel structure. With it, it is possible to make progress in other parts of the project such as mooring, and layout of components. Secondly, we have determined the buoy’s buoyancy, both on paper and in practice, and thus we have confirmed that it is certainly floatable. Thirdly, we have researched, selected and bought all the necessary parts that make up a complete mooring system. In this way we are sure that once the buoy is placed in the river, it will not run away. Thirdly, we have chosen a microcontroller that best suits the buoy, and partially programmed it so that it is possible to operate the wind direction sensor. Furthermore, we have the wind and CTD sensors, microcontroller, GNSS receiver, SD card socket, and lamp. Lastly, we have put a lot effort into the market analysis, ethics, and sustainability. Of course, it would not be possible to accomplish all of this individually. It took an organized and tuned team work to arrive to this point. However, we did not always cooperate perfectly; it was especially hard for us in the beginning when we barely knew one another. With time, however, we started displaying better and better team work qualities, e.g. we divided work between ourselves, and held frequent meetings at ISEP. As a result of the 4 month work we have definitely improved our teamwork skills. We know better how to cooperate, how to express and receive criticism, how to come to a mutual agreement etc. Nevertheless, we cannot consider our final work as a complete success as there are still many aspects of the buoy that need to be finished, as we discuss in section //7.2 Future Developments.//+This project has proven to be exactly what we thought it would be: difficult and complex, yet interesting and educationally valuable. Before we even started the actual work, we first needed to learn a considerable amount about different types of buoys - what they consist of, and how they perform their functions. It took us quite a lot of time, but it allowed us to have a better view on how to get started and then proceed with further work. There were many things we needed to consider, discuss and decide on. This included, for example, the anchor, lamp, and microcontroller. The two tasks that took up a considerable amount of time and effort were the structure and programming. At this point we regret that we did not have more experience in these fields before beginning the project; perhaps then we could achieve more and with a better quality. Nevertheless, as a result of working on this project, we have all broadened our knowledge in many different ways: we know a lot about buoys, sensors, anchors, buoyancy etc.  In a general view, we believe the project was a success. First of all, we have managed to design and acquire the steel structure. With it, it is possible to make progress in other parts of the project such as mooring, and layout of components. Secondly, we have determined the buoy’s buoyancy, both on paper and in practice, and thus we have confirmed that it is certainly floatable. Thirdly, we have researched, selected and bought all the necessary parts that make up a complete mooring system. In this way we are sure that once the buoy is placed in the river, it will not run away. Moreover, we have chosen a microcontroller that best suits the buoy, and partially programmed it so that it is possible to operate the wind direction sensor. Furthermore, we have the wind and CTD sensors, microcontroller, GNSS receiver, SD card socket, and lamp. Lastly, we have put a lot effort into the market analysis, ethics, and sustainability. Of course, it would not be possible to accomplish all of this individually. It took an organized and tuned team work to arrive to this point. However, we did not always cooperate perfectly; it was especially hard for us in the beginning when we barely knew one another. With time, however, we started displaying better and better team work qualities, e.g. we divided work between ourselves, and held frequent meetings at ISEP. As a result of the 4 month work we have definitely improved our teamwork skills. We know better how to cooperate, how to express and receive criticism, how to come to a mutual agreement etc. Nevertheless, we cannot consider our final work as a complete success as there are still many aspects of the buoy that need to be finished, as we discuss in section //7.2 Future Developments.//
 ==== 7.2 Future Developments ==== ==== 7.2 Future Developments ====
 Although we have already put much effort into the project, and a lot has already been accomplished, there are still many goals to achieve. Some of them are highly important and cannot be omitted if the buoy is ever to be placed on the river. On the other hand, some are just possible future additions that could make the buoy more functional. \\ Although we have already put much effort into the project, and a lot has already been accomplished, there are still many goals to achieve. Some of them are highly important and cannot be omitted if the buoy is ever to be placed on the river. On the other hand, some are just possible future additions that could make the buoy more functional. \\
-First of all, the fibreglass hull needs to be made completely watertight. Without this, there is a risk that water might get in and destroy the electronics, and maybe even cause the buoy to sink. The hull  can be made watertight by placing on it a “rubber skirt” (Figure 7 1) – a piece of rubber tape that is permanently attached to the cover’s outer surface, near its bottom edge, so that when the cover is in place, the tape can create a tight connection with the hull body’s outer surface, thus preventing the access of water.+First of all, the fibreglass hull needs to be made completely watertight. Without this, there is a risk that water might get in and destroy the electronics, and maybe even cause the buoy to sink. The hull  can be made watertight by placing on it a “rubber skirt” (Figure 7-1) – a piece of rubber tape that is permanently attached to the cover’s outer surface, near its bottom edge, so that when the cover is in place, the tape can create a tight connection with the hull body’s outer surface, thus preventing the access of water.
  
 {{:figure_7-1.png?200|}}\\ {{:figure_7-1.png?200|}}\\
 **Figure 7-1 "Rubber skirt"**  **Figure 7-1 "Rubber skirt"** 
  
-Another method that can be applied is to duct tape the groove between the cover and the hull body. However, it has three disadvantages: it is time-consuming, unprofessional, and most importantly - uncertain, once it might work, and once not. The best solution, but also most radical, would be to create another fibreglass hull whose cover would have a different geometry and features. As far as water tightness is concerned, it is also necessary to acquire appropriate watertight connectors for the interfaces. Secondly, the remaining components, i.e. communication module, GNSS antenna, batteries, communication module, and box for the hardware, need to be acquired. Once all these components are present, they must be somehow arranged, some inside the hull and some on the steel structure, and connected. Moreover, it is necessary to finalize the software and set it running. In this way the buoy will be able to perform its primary purpose: collect, store and send data. Another important feature that is needed to be added is a fibreglass cover for the lower part of the steel structure, as seen in Figure 7 2. Its purpose is to surround the ballast, and space around the tubes so as to protect the CTD and prevent things from deposing on the ballast. Of course, before putting the buoy in the river, some tests would need to be carried out to check if all these modifications are in working order.+Another method that can be applied is to duct tape the groove between the cover and the hull body. However, it has three disadvantages: it is time-consuming, unprofessional, and most importantly - uncertain, once it might work, and once not. The best solution, but also most radical, would be to create another fibreglass hull whose cover would have a different geometry and features. As far as water tightness is concerned, it is also necessary to acquire appropriate watertight connectors for the interfaces. Secondly, the remaining components, i.e. communication module, GNSS antenna, batteries and box for the hardware, need to be acquired. Once all these components are present, they must be somehow arranged, some inside the hull and some on the steel structure, and connected. Moreover, it is necessary to finalize the software and set it running. In this way the buoy will be able to perform its primary purpose: collect, store and send data. Another important feature that is needed to be added is a fibreglass cover for the lower part of the steel structure, as seen in Figure 7-2. Its purpose is to surround the ballast, and space around the tubes so as to protect the CTD and prevent things from deposing on the ballast. Of course, before putting the buoy in the river, some tests would need to be carried out to check if all these modifications are in working order.
  
 {{:figure_7-2.png?200|}}\\ {{:figure_7-2.png?200|}}\\
Line 1777: Line 1776:
 [106] Alibaba, “Alibaba,” 07 June 2013. [Online]. Available: http://www.alibaba.com/product-gs/633898401/High_Quality_Black_Anti_Corrosion_Humidity.html. [Accessed 07 June 2013].\\ [106] Alibaba, “Alibaba,” 07 June 2013. [Online]. Available: http://www.alibaba.com/product-gs/633898401/High_Quality_Black_Anti_Corrosion_Humidity.html. [Accessed 07 June 2013].\\
 [107] I. A. (. S. Bhd, 07 June 2013. [Online]. Available: http://www.iasb.com.my/webshaper/pcm/files/ICS/GEWISS/SelGuideSurfaceMount.pdf.\\ [107] I. A. (. S. Bhd, 07 June 2013. [Online]. Available: http://www.iasb.com.my/webshaper/pcm/files/ICS/GEWISS/SelGuideSurfaceMount.pdf.\\
-[108] Bulgin, „Bulgin connectors,” Bulgin, 2012. [Online]. Available: http://bulgin.co.uk/. [Geopend 03 June 2013].\\+[108] Bulgin, „Bulgin connectors,” Bulgin, 2012. [Online]. Available: http://bulgin.co.uk/. [Accessed 03 June 2013].\\
 [109] Davis instruments, “Anemometer 7911,” [Online]. Available: http://oceancontrols.com.au/datasheet/ocean/kta250_7911_spec_Rev_E.pdf. [Accessed 7 May 2013].\\ [109] Davis instruments, “Anemometer 7911,” [Online]. Available: http://oceancontrols.com.au/datasheet/ocean/kta250_7911_spec_Rev_E.pdf. [Accessed 7 May 2013].\\
 [110] B. W. Kernighan and D. M. Ritchie, “The C programming Language,” 1988 . [Online]. Available: http://net.pku.edu.cn/~course/cs101/2008/resource/The_C_Programming_Language.pdf. [Accessed 28 May 2013].\\ [110] B. W. Kernighan and D. M. Ritchie, “The C programming Language,” 1988 . [Online]. Available: http://net.pku.edu.cn/~course/cs101/2008/resource/The_C_Programming_Language.pdf. [Accessed 28 May 2013].\\
-[111] STMicroelectronics, „STM32F3 Discovery kit firmware package,” 2013. [Online]. Available: http://www.st.com/web/en/catalog/tools/PF258154. [Geopend 04 June 2013].\\ +[111] STMicroelectronics, „STM32F3 Discovery kit firmware package,” 2013. [Online]. Available: http://www.st.com/web/en/catalog/tools/PF258154. [Accessed 04 June 2013].\\ 
-[112] Davis, „Davis Anemometer documentation,” 2013. [Online]. Available: http://www.davisnet.com/weather/products/wx_product_docs.asp?pnum=07911. [Geopend 12 June 2013].\\+[112] Davis, „Davis Anemometer documentation,” 2013. [Online]. Available: http://www.davisnet.com/weather/products/wx_product_docs.asp?pnum=07911. [Accessed 12 June 2013].\\
 [113] The Free Dictionary, “Anchor,” 2013. [Online]. Available: http://www.thefreedictionary.com/anchor. [Accessed 3 April 2013].\\ [113] The Free Dictionary, “Anchor,” 2013. [Online]. Available: http://www.thefreedictionary.com/anchor. [Accessed 3 April 2013].\\
 [114] The Columbia Encyclopedia, 6th ed., “Anchor,” 2013. [Online]. Available: http://www.encyclopedia.com/topic/anchor.aspx. [Accessed 2 April 2013].\\ [114] The Columbia Encyclopedia, 6th ed., “Anchor,” 2013. [Online]. Available: http://www.encyclopedia.com/topic/anchor.aspx. [Accessed 2 April 2013].\\
Line 1829: Line 1828:
  
 {{:appendix_a._mooring_a_buoy.pdf|}} {{:appendix_a._mooring_a_buoy.pdf|}}
 +
 +{{::appendi_b_x-buoy_-_technical_drawings.pdf|}}

Trace:

QR Code
QR Code report (generated for current page)