In Stuttgart, there is now a Hackergarden Meetup group that tinkers with whatever the people showing up want to tinker with.
In the 1st edition I was doing some hacking on Arduino where two Arduinos were transmitting data over an encrypted radio via a RFM69 radio chip. This setup is described on the Codecentric blog.
Now in the 2nd edition we wanted to build on this and control a servo motor on one Arduino remote from the other one. This video shows the end result:
On the left you see a potentiometer, that is read out and the value is then shown on the Neopixel ring. The value is also transmitted via RFM69 chip to the other Arduino that has the receiver and which then drives the servo.
The setup on the server side looks like this:
On the receiver side we used a "normal" setup like the one described on the before mentioned report. We had an issue for a while, as the servo was on a port that was also used by the RFM69 code, but once we fixed that, it worked.