This is just a post to keep this information available, as I could only find it in one location!
I bought a FrSky S6R stabilised receiver and didn’t want to spend another £12 on a FrSky STK. I came across a handy post on RCGroups where pawelsky created a custom STK using a cheap Arduino Nano and some clever code.
You’ll need to buy a Arduino Nano, which can be bought for less than a fiver from most online market places. There are a few varieties, so if you are unsure which to choose, look for one with the 328 chip. Other varieties will still work, but my examples below use the 328.
You’ll need some software to write the .hex code onto your Nano. This is free and works well: http://russemotto.com/xloader/
The first step is to connect the servo cables and a jumper to the pins on the Nano. I have attached a diagram below. Credit to the author, who I believe is pawelsky.
You now need to establish which COM port on your computer the USB is plugged into. To do this, open Device Manager on the computer in question and look for the port section. When you plug in the USB, the COM port will show up. Different USB ports are different COM ports.
In my example, when I plug the Nano in, it shows up on COM4. I then choose this option in Xloader as shown below. Note that you should choose the Device type based on the chip your Nano has. You’ll usually have to read the manufacturer’s or seller’s description to ID your chip. The Baud rate may also be different for other chips.
Click Upload and wait for the message at the bottom of the window to read “…bytes uploaded”. You can then close the window and open up the FrSky PC Config software.
This is the annoying part! The FrSky software seems really buggy. I have version 1.8.4 and it either takes a few minutes to connect or just doesn’t connect at all. This is confirmed by owners of the official STK stick as well, so it isn’t a Nano issue.
First of all, select the COM port for your Nano. This is the same as the one in the Xloader software (unless you changed the USB port).
Select Open to open the connection and then Read to read the receiver via the Nano. This could take a few minutes and may appear to be doing nothing. When it connects, you should see the numbers in the Accelerometer boxes change as you move the S6R. If you get nothing after 5 minutes, unplug it and try again. You could also try different USB ports (remembering to change the COM port).
Some people have reported that the S8R software also works and may be less buggy than the S6R software?!
I have also connected with the jumper set to the wrong side, which is interesting!
Lastly, it is worth noting that the S6R needs your radio transmitter to have 12 channels assigned. The receiver does some internal configuring with the later channels (for example, assigning a 3 position switch on CH10 allows you to change between Auto Level, Stabilise and Off). Without all channels assigned, the S6R acts like a dumb X6R. CH11 can be left unassigned if you are setting up a Delta/Flying Wing in the Config PC software.