Skip to comments
Thanks for the idea DJ !
The other day DJ suggested an easy way to make a touch sensor, see this thread
https://www.ez-robot.com/Community/Forum/Thread?threadId=7692.
So I started playing with that idea and made a couple of touch sensors by soldering a piece of foiling tape (I "borrowed" some from my wife's stain glass supplies) to the end of a wire. I attached the wire to an ADC Port and put the foiled end on the robot. Wrote a script and it works pretty good.
Here's a picture of the sensor.
A short video of them working.
Thanks for the idea DJ !
By bhouston
— Last update
If you touch the shoulder, the robot should automatically look into the right direction. same function as a NAO robot and very human like.
A conductive mesh over the silicone caps on the fingertips would do a good job.
Now you have to script your Inmoov to serve wine to your wife into a bare stain glass...
Ask Richard how to.
I second that "great idea"! Love your Inmoov, and can't wait to get started on
mine, once I figure out space to build it.
I would be interested in the script you wrote, can you post it?
Cheers,
Chris.
Here's the code.
Code:
In the video I didn't have it running in the "loop" and I activated the script with a voice command. If it is running in the loop it will sense your touch whenever you touch a sensor. I had to play with the values using the ADC Value control to know what settings to use.
Working on a HDMI cable to fit in my Inmoov's arm, I discover a conductive mesh that can fit easily on hand's fingers.
Does anyone have any thoughts on why these sensors won't work any more?
Thanks
I would recommend separating the tinfoil from the inmoov and seeing if it works. It might just be grounded too well from moisture over time - or the garage humidity has changed drastically since the last attempt.
Do you see any problems doing that?
The response from your body to the copper foil will change based on humidity, cloud cover, metal in the area, and moisture of your skin. The better antenna you are the more signal you can send into the ADC port. The dry environment you are in probably isn't going to help in terms of being an antenna.
Seems like you were also trying to use a capacitive effect. If you'd like us this type of method you won't need a capacitor in line with the copper foil as this will only work if you are a good antenna. Since capacitors are transparent to AC voltage the signal will pass through the capacitor to the ADC and it'll work the same as the original way you were trying.
If you want to build a touch sensor that is a bit more reliable look into the sigma-delta concept. The concept does require you to have a capacitor attached to each copper pad, but it won't be in-line it will be attached from sensor to ground. Then you will need to charge that capacitor with 3.3V (maybe with a digital pin or use a single transistor to apply 3.3V to all the touch sensors). Once charged you can then start reading the ADC, then when the touch sensor is touched the capacitor will drain through the body (not enough voltage to hurt anything). You can detect the amount/length of touch based on how much time the capacitor takes to drain.
I'm sure I'm not explaining it very clearly but if you google Sigma-Delta touch sensing you'll get a better explanation
The data sheet is here. There are some other configurations as well.
http://www.interlinkelectronics.com/FSR408.php
They can be easily hooked up via a voltage divider. Here is a back and forth I had with Rentaprinta a while back concerning their use:
http://www.ez-robot.com/Community/Forum/Thread?threadId=8123