For a long time I've been thinking (like many others) about adding sensors to my hexapods for TA (terrain adaption). This might be a waste of time since Jim already has proven to make some excellent microswitch foot sensors.
Anyway, my idea was to use FSR sensors between SES brackets. Instead of having the sensor/switch on the foot I wanted to try adding a sensor in other parts of the leg, making the whole leg "ground sensing".
My first attempt was to add a sensor inside the femur part, this is something I tried for about a year ago:
I'm using a 3mm screw for adjustment.
Using a little tape sticker for protecting the FSR
To make a long story short, I wasn't satisfied with the result.. And I didn't like the idea of drilling new holes in the SES brackets either.
But I didn't wan't to give up the FSR yet..
This time I thought of placing the FSR inside the coxa, or between the coxa and femur bracket to be more correct. Yesterday I made two very simple parts of 1,5mm aluminium. The parts are mounted to the ASB-04's using the small counter sink screw that came with a pair of the ARF-01's (SES feet) (I wish I had more of those screws..
As you can see the plate without the FSR is a little shorter to make space for the rubber bumper pad. The two plates are mounted together with two rubber parts. Guess where they come from..
Pardon the shiny metal, I didn't got time for sandblasting. After all this is just a prototype for testing.
Optionally, I made space for a spring between the brackets. At first I didn't use the spring since the weight of the leg will force the brackets apart anyway.
Closeup of the rubber bumper mounted:
The two plates are mounted together with two screws and the rubber parts I mentioned:
Some pictures of the final result:
I'm using a longer screw between the brackets (where I mentioned the spring). Adjust this screw just enough to make a little gap between the FSR and the rubber bumper pad:
From another angle (the coxa side):
And from the femur side:
Example picture with servos:
I've done some small testing and it seem to work perfect so far. I also need to do some more testing on a robot to see if it fails under certain conditions. I'm still not convinced if this solution work as good as an actual foot sensor. Anyway, I want to try this on my T-hex. I just need to get more of those small counter sink screws..
Any comments are appreciated.