2014-09-21

DIY drone - tutorial for developers | Part 8 - Hooking up the FC

Testing out the receiver (RX) with the flight controller (FC)


Let's connect the RX to the FC and test it out like that.

First upload the firmware to the FC, then leaving the USB cable plugged in you can actually power up the FC and try to see if the RX works with it.

Here is the cabling detail :



Some explanations
First the RX needs to be powered this time, by the FC.
The red and black wires are connected to the 2 first pins : 5V and GND on the FC
They connect on the RX side to the BATT +- (it is not obvious to see from the marking, check out the picture).

Then, you'll need to connect the signal lines for the channel (do you remember from the previous parts, the internal ones), to the correct channels on the FC.

There is some terminology translation from the plane jargon to the helicopter jargon to do :

ELEV (elevator) connects to PITCH on the FC
AILE (ailerons) connects to ROLL
THRO (throttle) connects to THROTTLE
RUDD (rudder) connects to YAW

4 channels + 2 power = 6 wires.

Now fire up multiwii GUI or, like I prefer, use an OTG cable and connect your FC to your android phone and use this app.

Pair your RX with your TX.

Go to the Config Tab of Ez-Gui and set it up to connect through USB like this :



On the Ez-Gui click MW Connect (at the top) then once it has done that successfully, click Radio from the main menu :


You should see this screen :


Check if the commands are moving the same way you are moving them on your controller.

If they are reversed, setup the channel reversed on your controller.
On the Devo 10 you need to :

Press ENT to enter in the menu ...



then ENT again to enter in Function ...


then ENT again to enter in Reverse switch ...


then UP/DN to select the channel and R/L to change them ...

I had to put Reverse for Aileron and Rudder.

(to exit the menus press EXT)

Now in the RC world, the input are normalized between 1000 and 2000.

Try to adjust, in the similar fashion, Travel Adjust so all your sticks shows ariund 1000 at their minimum and 2000 at their maximum.

For this I had to set them up at around 125% and for one channel it did not have any effect. Try to make it as good as possible.

Then it is time to put it all together and make the ESC final calibration