Controlling a device through PWM
This document will walk you through how to control or manipulate a device through PWM (Pulse-width modulation) on PRSIM Sky.
First we must prepare the aircraft to accept the device. Most devices (such as a servo) operate with a signal, positive voltage input and a ground. Below are the steps to remove the FAD Cover, preparing a cable and changing parameters in PRISM Sky to toggle the device.
Requirements:
1.) PRISM Sky on AOS 1.3.6 or newer.
2.) KONTACT with Auterion Mission Control 1.0.7 or newer.
3.) 2mm socket head driver.
4.) Small phillips head screw driver.
Hardware:
Removing the FAD cover:
Step 1.) Remove the 3 bolts circled in the below picture
Step 2: Remove the right rubber seal highlighted in green and cut an X pattern in it using a knife. This will allow it to still be relatively water tight however it will let a cable pass through it. Replace it back in its original location marked in orange.
Step 3: You will now have to make a custom wire that will connect to your device. For this example, we will show a JST-GH 5 Pin-> female servo connector. Simply lap solder the wires together and cover them with heat shrink. Be careful to line up power + to power + and signal to signal!
| Pin | JST-GH | Servo Connector |
|---|---|---|
1 | DNP | N/A |
2 | DNP | N/A |
3 | Power + | Signal |
4 | Signal | Power +5v |
5 | Ground | Ground |
Step 4: Once the cable is complete, plug it into the FPV Servo port on the FAD board on PRISM Sky and route the cable out through the cut grommet and re-install the FAD Cover.
Step 5: NOTE: The FPV Servo port on FAD outputs 5v, please be sure your device can handle this voltage. If so, connect your servo or device to the cable. With the motor arms in the folded/travel position, power up PRISM Sky and KONTACT to begin the software programming.
Software:
Step 1: On KONTACT; open AMC and enable Advanced mode by clicking on the paper airplane (top left) 5 times very quickly.
Step 2: Click on the paper airplane and navigate to Vehicle Setup -> Parameters. Please change the below parameters:
| Parameter | Value |
|---|---|
PWM_AUX_MIN1 | 1000 |
PWM_AUX_MAX1 | 2000 |
MNT_MODE_OUT | AUX |
Step 3: Navigate out of Parameters and click on Joystick -> Button Assignment.
Step 4: Press the button on KONTACT that you want to use to trigger the function to find which button it is within the software. Click the drop down menu and select "Toggle Servo 1".
Step 5: Press the assigned button to make sure the servo or device is toggling properly.
NOTE: It is normal for the servo/device to be un-powered until the button is assigned the function; Skynode does not send signal to the device until a button is chosen for the trigger.
Tuning:
If you need to tune the range of motion of the servo or the "trigger range" for the device, please tune the min and max PWM values to achieve your desired outcome. You can adjust the param "PWM_AUX_MIN1" and "PWM_AUX_MAX1" values to adjust the total range of the servo or device to achieve the desired outcome.
It is normal for the device/servo to not operate when the aircraft is first powered on. Skynode does not send signal to the device until the trigger button is pressed. We recommend "triggering" the device on every boot up once KONTACT is connected the PRISM Sky. This will set the device to the "min" value and then be ready to function.
Additional Servos
It is possible to add more than one servo or device to PRISM Sky and control all three. The FPV Servo port on the FAD board is capable of supporting two servos. The following pinout can be used:
| Pin | Function |
|---|---|
1 | Ground |
2 | Aux Servo 2 Signal |
3 | Power +5v |
4 | Aux Servo 1 Signal |
5 | Ground |
A "Y connector" would have to be made to power Aux Servo 2 for Power + and Ground. For adjusting the Aux min and max values; please review the above steps and repeat them for Aux 2.
A third servo can be plugged into the MR30 connector on the FAD board. The following pinout can be used:
NOTE: This is 24v out! Please be careful of plugging in devices that cannot handle 24v.
The connector can be found HERE
For adjusting the Aux min and max values; please review the above steps and repeat them for Aux 3.
| Pin | Function |
|---|---|
1 | Signal |
2 | Power +24v |
3 | Ground |
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