Pressure sensors on the feet
Pressure sensors on the feet
by JonHylands
Thu Feb 08, 2007 7:45 pm
So, I was looking again at the bottom of the feet, and I realized the funny keyhole-shaped holes looked like the right size for some pressure sensors I had.
http://www.bioloid.info/tiki/tiki-index.php?page=Foot+Pressure+Sensors
I'm going to design another tiny custom PCB with an ATmega168 onboard, with four analog inputs (and the appropriate connectors and such) for having four of these pressure sensors at the bottom of the Bioloid's foot.
This board will fit inside the foot, with the ankle bracket in the "normal" position, and will daisy-chain with the ankle pitch servo (which has an open connector).
This will give us another custom bus sensor for each foot...
- Jon
http://www.bioloid.info/tiki/tiki-index.php?page=Foot+Pressure+Sensors
I'm going to design another tiny custom PCB with an ATmega168 onboard, with four analog inputs (and the appropriate connectors and such) for having four of these pressure sensors at the bottom of the Bioloid's foot.
This board will fit inside the foot, with the ankle bracket in the "normal" position, and will daisy-chain with the ankle pitch servo (which has an open connector).
This will give us another custom bus sensor for each foot...
- Jon
by JonHylands
Fri Feb 09, 2007 10:37 pm
The link is on the wiki page:
http://www.trossenrobotics.com/store/p/3217--2-Inch-Force-Sensing-Resistor-FSR-.aspx
Given that the foot is basically a stiff flat rectangle, more than four sensors will only help if you are walking on seriously uneven terrain.
- Jon
http://www.trossenrobotics.com/store/p/3217--2-Inch-Force-Sensing-Resistor-FSR-.aspx
Given that the foot is basically a stiff flat rectangle, more than four sensors will only help if you are walking on seriously uneven terrain.
- Jon
by Goldrake
Fri Feb 09, 2007 11:21 pm
What do you think about this one?
http://www.trossenrobotics.com/store/p/ ... -FSR-.aspx
Is it flexible? Can be curved on a leg? I don't understand also if it's a touch sensor, does it give the position where the force hit on the square?
thank you
http://www.trossenrobotics.com/store/p/ ... -FSR-.aspx
Is it flexible? Can be curved on a leg? I don't understand also if it's a touch sensor, does it give the position where the force hit on the square?
thank you
by JonHylands
Fri Feb 09, 2007 11:26 pm
I have a couple of those ones as well.
It responds to pressure anywhere, but you have no idea where. The nice thing with the small round ones is they fit inside the notches cut on the foot.
That one (big square) could be fit onto a curved surface, although I'm not sure how well it would work.
- Jon
It responds to pressure anywhere, but you have no idea where. The nice thing with the small round ones is they fit inside the notches cut on the foot.
That one (big square) could be fit onto a curved surface, although I'm not sure how well it would work.
- Jon
by JonHylands
Sat Feb 10, 2007 1:41 am
I'm going to be putting some kind of rubber pad on the bottom of the feet, which will cover up those sensors. The sensors actually stick down below the bottom plane of the foot, so the pad will contact the sensor nicely.
Right now I'm planning on using a silicone pads that I cut out of the bottom of a silicone baking pan I bought ($6.99). The silicone is about 1.5mm thick, wihch is perfect. The only real trick is going to be getting it stuck to the feet - its pretty non-stick. I'm going to try and use some silicone (the kind you get out of a tube), and rough up the surface of the pad so it will stick better.
- Jon
Right now I'm planning on using a silicone pads that I cut out of the bottom of a silicone baking pan I bought ($6.99). The silicone is about 1.5mm thick, wihch is perfect. The only real trick is going to be getting it stuck to the feet - its pretty non-stick. I'm going to try and use some silicone (the kind you get out of a tube), and rough up the surface of the pad so it will stick better.
- Jon
by JonHylands
Wed Apr 25, 2007 6:56 pm
I have a few new boards, ready to be populated.
On the left is my original prototype, which works, although it has a couple issues. On the right is my new board, which I haven't had a chance to populate yet.
I've been just crazy busy for the last few weeks, and have had very little time to put towards this board or the IMU board. I'm planning on getting the first 10 IMU boards populated this weekend, so hopefully I'll have some good news next week.
To answer your question, you feed one pin from the sensor into an A/D port of a micro-controller, with a pull-down resistor (10K). The other pin of the sensor gets +5 volts.
- Jon
On the left is my original prototype, which works, although it has a couple issues. On the right is my new board, which I haven't had a chance to populate yet.
I've been just crazy busy for the last few weeks, and have had very little time to put towards this board or the IMU board. I'm planning on getting the first 10 IMU boards populated this weekend, so hopefully I'll have some good news next week.
To answer your question, you feed one pin from the sensor into an A/D port of a micro-controller, with a pull-down resistor (10K). The other pin of the sensor gets +5 volts.
- Jon
