Posts: 33
Joined: Sat Sep 22, 2012 9:07 am

Control 56 servos with the Raspberry Pi & the PiXi add-on...

Mon Oct 06, 2014 10:24 pm

Hi everyone,

In the run up to launching our PiXi Kickstarter project, we got distracted trying to create something interesting. A while back we showed how it was possible to control 12 servos directly with the PiXi add-on but we always knew we could do more.

Having recently seen several examples where processors including both the Raspberry Pi and Arduino have been used to generate PWM signals from basic I/O using software to emulate a hardware based PWM controller, we thought that it was worth showing that the PiXi could drive a much larger number of servos without taking up any processing power of the Raspberry Pi. So you still have all that wonderful processing power at your disposal.

We modified the design in the PiXi FPGA to change "12" PWM channels to "56" (actually it really was almost as easy as changing a single number!), re-compiled the FPGA design and built some hardware to test it. This is what we came up with:

If anyone is interested we'd be happy to go into more details on how we did this inside the FPGA, how to make the changes, re-compile the design and re-load it. All of which is possible without any expensive software or tools.

Thanks for looking and please feel free to ask any questions.

Astro Designs
PS Apologies for the sound of the rain in the background :)

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