Foot contact switch sensor for Spotmicro quadruped by Quadrupede

Last crawled date: 3 years, 1 month ago

Reliable foot contact switches for KDY0523's Spotmicro robot dog
TLDR: foot contact switch using force-sensitive resistors requiring only two additional printed parts and some electronicsVideo
Introduction
I tried to design the foot contact switches as easy and cheap as possible while maintaining the usual Spotmicro design. Basically, there are two force-sensitive resistors (FSR) in parallel integrated into a voltage divider. By measuring the voltage over the resistors, we can determine if the foot touches the ground. There is a LED placed in the foot for visual feedback.
Instructions
In addition to the provided parts, you need the usual Spotmicro foot from KDY0523 printed in flexible filament. Make it as flexible as possible.
print the remaining parts in PLA with 10% Infill
make sure to remove all support material
solder all parts according to the given scheme
use tape to fix everything in place. The tapes main purpose is to provide a counteracting force in order to push the foot away to relieve the resistors
Electronic parts
8 force-sensitive resistors such as RP-S5-ST
4 or 8 LEDs with 3mm diameter
matching resistors
any microcontroller, I am using an Arduino Nano (take a look at my Github for code)
Implementation in control software
I did not implement the foot feedback into my control software so far because I am still waiting for some additional FSRs to complete my setup. If you managed to implement them in your code, feel free to share it!
My code and current progress can be found at https://github.com/ThomasSchnapka/quaro
Troubleshooting
If your setup is not working, try the following:
make sure the "spacer" is able to move freely without getting stuck. This might be because of leftover support material
choose an appropriate threshold for your voltage
filter the voltage signal if necessary (you may orientate on my code)