Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors. Author: Carlos López Translation by Manolo Hdez-Peña M. Revised by Jaime Pirnie Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project 1. 2. 3. 4. 5. 6. Intro Building the instrument Connecting the servos card (by Borja Perera) Software configuration Working with MS Flight Simulator Working with X-Plane Intro Using the servo motors card, we can make any analog instrument work like a real instrument in a real airplane. Although in the modern cockpits there are less and less analog instruments, there always will be the stand-by gauges. In the case of the Boeing 737 and Airbus A320 (the most popular cockpits) the stand-by gauges are: attitude indicator, altitude indicator, IAS indicator, and RMI. UIT these stand-by instruments, we could fly anywhere in the case of a general failure in the glass cockpit system. Other gauges that can be simulated using servo motors are: flaps position indicator, brakes hydraulic pressure indicator, etc. This winter ’04 I was gifted with an un-calibrated attitude indicator, so I decided to make my simulated gauge using it. I would like to thank the company “Flight Training Europe” (Xerez) and especially to Manuel Represa for this real gauge. If you want to know how the real gauge works, try these links: Gyroscope: http://www.ciencia-ficcion.com/glosario/g/giroscop.htm Gyro properties: http://inicia.es/de/vuelo/INS/INS22.html Attitude indicator: http://inicia.es/de/vuelo/INS/INS26.html Page 2 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Building the instrument Since our simulated cockpit has no movement, instead of keeping the horizon fixed and moving the body/shell of the gauge (the real gauge acts this way), we will move the horizon inside the fixed position body/shell of the gauge. This is the gauge we are taking apart. Here you see the front of the gauge. The picture to the right shows the rear of the gauge. Looking at the rear, we see the hole in the center. This is the axle for the inner body and the air intake (the inner gyro turns with an air stream). The air outtake is the upper left hole, which is connected to an air pump. Lets take out the rear lid using a small screwdriver. With an allen wrench, we will take out the center piece. We can now see the axle with its bearings. This is where the inner body is mounted. Page 3 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Side view where we can see the inner body... Now we will take out the front piece (with the crystal) and the needle that indicates the bank angle. The gyro is still mounted in the inner body. ... and the mechanism for pitch indication. All the pieces in the order that we have taken them outo. Another view of the pieces that indicate our flight attitude. Page 4 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Another view of the flight attitude indicator pieces. We can see some counterweights and screws to calibrate the instrument. This is a closer view of the inner body. We can see how the piece move to indicate pitch. We can now take out the inner body (with the gyro on it). The red line indicates the air circuit that makes the gyro turn. We can now take out the gyro and place a servo in its place. Page 5 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Here we can see the body (we will use it) and the gyro (we can discard it). Lets remake our attitude indicator. We have to mount a servo on the inner body. This servo will control the pitch movement. We will mount these pieces in this position. Here are all the pieces that have no use. We can see the inner blade that moves the gyro by the air stream. We will use a Hitec servo, model HS-311. This servo includes different gears and accessories. We will use a piece with a cross shape. A closer view. All the elements except the servo and the plastic piece are the original ones. Only the gyro is substituted by a servo motor. Page 6 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project The mechanism that will move the pitch indicator. The servo already mounted. It has been fixed to the body with a plastic zip tie. Another picture showing the mounted servo. Next step is to mount the rest of elements. Here we see the inner body inside the outer one. Now we fix the reference horizon and then... ... the horizon moved by the servo. Page 7 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project A side view. And the mechanism in a levelled flight position, while a descent, and while ascending. Now we will fix the bank scale which will be moved by the second servo motor. To backlight the gauge we will use four little 12 volts light bulbs. Page 8 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project This is how it looks when backlit. Once we have finished with the inner part, we will mount a second servo motor that will turn when rolling. We will use a board (with the corresponding holes) where to mount the second servo. Now we will use a Futaba servo motor, model S3001. A closer view of it. The hole must be in line with the inner body axle. Page 9 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project We can now calculate the final position of the servo and an extra hole for the cables. This picture shows all the elements mounted. A side view of everything mounted. Not all the servo motors have the same connections, so we’ll have to check them. Page 10 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Now we are finished. This is the final look of our simulated attitude indicator. The final step is to connect the servos to the servos cards and see if everything works ok. If you want to see some videos with the gauge working, try these links: http://www.micabinadevuelo.com/periodo-3-servo/Servos_3_L.wmv http://www.micabinadevuelo.com/periodo-3-servo/Servo_0001.wmv http://www.micabinadevuelo.com/periodo-3-servo/Attitude_Indicator_L.zip Page 11 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Connecting the servos card (by Borja Perera) We have two options: build our own card or buy it from Opencockpits. If you choose the first option, you can download all the information from Opencockpits. We are using a card bought from Opencockpits. The servos card is connected to 8 master card outputs per servo (two servos can be controlled with one card). To control the first servo, we will use the connector below that has 10 pins. Pin #1 is not used; pin #2 is a common GND (common outputs GND to avoid noise); the rest of pins are connected to eight consecutive master card outputs. Now we will connect servo number 1 to this card by the upper left connector. It has three pins: yellow (servo control), red (+), and black (GND). If we want to connect a second servo, we will proceed the same way but will use the 8 pin connector on the right hand side and the other three pin connector above. We will feed the card with 4.8 volts (4.5 to 5 volts is OK) through the connector on the left hand side (positive and GND is shown in the picture). Page 12 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Software configuration We are going to use the IOCards software in the following order: We start with the controller software to see if what we have done up until now works properly and to check the movement limits of our servos. Once started, we will click Start and activate the checkbox Servo Control. In my configuration, servos are connected to outputs numbers 11 to 18 for pitch and from 19 to 26 for bank. We write in the field First Output the first output where the servo is connected and in the field Value a number between 0 and 255. First we look for the centered position of the servo. In my case the centered values are 145 for servo-1 and 131 for servo-2: Now we write down the values for the limit positions (90º for bank and 60º for pitch, once the real gauge has been modified) and start the second program. We will define two variables S_PITCH and S_BANK. We will assign two IOCGauges addresses (#2 y #3) and we will associate them with the functions PITCH and BANK: Page 13 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Under the functions tab we will define the following values: Then we will define the servos under the MOTORS-S tab with the values obtained from the controller software: Once this is made, we can save the file and we are ready to calibrate our attitude indicator and to test it with our favourite flight simulator. Page 14 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Working with MS Flight Simulator We will download first the file IOCGauges from www.opencocpits.com, follow the installation instructions and open the file IOCGauges.ini where we will set the values for maximum pitch and bank angles. In my case: Page 15 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project We will open iocard.ini file checking the following values: We will start the simulator and the IOCard and IOCGauges programs: Page 16 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Checking that both have connected with the simulator and one with the other via IOCP protocol (FSUIPC must be installed in the folder ‘modules’ in FS). We can make a test flight to see if the movements on the screens are the same as in our new analog gauge. If not we can make small changes in the IOCGauges.ini. Page 17 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project Working with X-Plane We don’t need FSUIPC nor IOCGauges if we use X-Plane. The control for analogue gauges is included in the XPLUIPC, library developed by Alberto Beaterio. For additional information on this DLL you can download it from www.opencockpits.com or directly from this link: XPLUIPC Ver. 1.1 Release 1 Once the library is installed, we just have to set the values for the maximun angle of pitch and bank in the XPLUIPC.ini. In my case: Page 18 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project We will open iocard.ini checking the following values: Finally we will run the simulator and the IOCards software: Note that FSUIPC is disabled and IOCP enabled. Then, from X-Plane menu, we can check the connection this way: Page 19 of 20 Tutorial on how to modify a real attitude indicator to be used with IOCards and servo motors IOCards Project We can make a test flight to see if the movements on the screens are the same as in our new analog gauge. If not we can make small changes in the XPLUIPC.ini. I would like to aknowledge the members of the developers of analog gauges (Fernando Brea, Borja Perera, David Pousada and Manuel Vélez) and to the software developers (Alberto Beaterio and Manuel Vélez) that make all this possible. Links to other pages related with analog gauges. Gyro principles Gyro properties http://www.ciencia-ficcion.com/glosario/g/giroscop.htm http://inicia.es/de/vuelo/INS/INS22.html Attitude indicator Video of an attitude indicator driven with servos. By Carlos López: http://inicia.es/de/vuelo/INS/INS26.html http://www.micabinadevuelo.com/periodo-3-servo/Servos_3_L.wmv http://www.micabinadevuelo.com/periodo-3-servo/Servo_0001.wmv http://www.micabinadevuelo.com/periodo-3-servo/Attitude_Indicator_L.zip Tutorial on how to build a dual flaps indicator. By Fernando Brea and Borja Perera Video of a dual flaps indicator driven by servos. By Fernando Brea http://www.opencockpits.com/modules.php?name=Downloads&d_op=getit&lid=117 http://fernandobrea.eresmas.net/flaps/flaps1.wmv http://fernandobrea.eresmas.net/flaps/flaps2.wmv Carlos López: [email protected] http://www.micabinadevuelo.com/ Page 20 of 20
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