Electrick: Low-Cost Touch Sensing Using Electric Field Tomography(yang-zhang.me)
yang-zhang.me
Electrick: Low-Cost Touch Sensing Using Electric Field Tomography
http://yang-zhang.me/research/Electrick/Electrick.html
22 comments
This is awesome. Does not compare to touchscreens, but wildly useful for hacking interactive real world objects. Would appreciate a DIY hardware guide from the creators and open source code for processing the signals. The full paper does have some detail but not sure if it's enough to run with.
This is cool. I wonder if in addition to changing the current injection electrode, dynamically varying the resistance at the electrodes can help increase the resolution.
Changing the resistance dynamically can change the current distribution on the surface. This can be used to change the gradient around the touch location to further refine the position. Edit: clarity and typos
Changing the resistance dynamically can change the current distribution on the surface. This can be used to change the gradient around the touch location to further refine the position. Edit: clarity and typos
Well I guess you have a topic for your next whitepaper. :D
I'm really excited to see electric field sensing mature like this, but I sense a potential problem with RF emissions down the road. Can this stuff get FCC class-B certification?
The paper seems to say they use 200 kHz sinusoidal waves for the field. If that translates directly into what I see in an FCC table of frequency allocations, then that is in the AERONAUTICAL RADIONAVIGATION regulated by FCC Rule Part Aviation (87) [1]. They are driving the signal at 6 Vpp (peak-to-peak), at most 0.42 mA current with the lowest-resistance spray. I don't know how to even crudely calculate radio interference from those specs, so would appreciate someone giving guidance on where to look for a start.
What worries me about this approach is the need for calibration. I don't see anywhere that indicates they've tested to see the effects of the wearing down of the topcoat and conductive spray layer upon the accuracy. It would be cool to be able to simplify a light switch installation to slap(electrodes)-spray-spray-calibrate, it would suck if I had to re-calibrate once every few years.
Now if we can figure out how to beam low-voltage, low-amperage power over building distances and through insulation, then we could remove a lot of copper runs. Beam just enough low power to drive and sense these kinds of control surfaces, and control relays sitting in front of the actual devices' electrical connections.
[1] https://transition.fcc.gov/oet/spectrum/table/fcctable.pdf
What worries me about this approach is the need for calibration. I don't see anywhere that indicates they've tested to see the effects of the wearing down of the topcoat and conductive spray layer upon the accuracy. It would be cool to be able to simplify a light switch installation to slap(electrodes)-spray-spray-calibrate, it would suck if I had to re-calibrate once every few years.
Now if we can figure out how to beam low-voltage, low-amperage power over building distances and through insulation, then we could remove a lot of copper runs. Beam just enough low power to drive and sense these kinds of control surfaces, and control relays sitting in front of the actual devices' electrical connections.
[1] https://transition.fcc.gov/oet/spectrum/table/fcctable.pdf
That's great detail, thanks for looking that up. The 200Khz wave may not be a big deal, but when you start getting strong harmonics then things really go south in your certification tests.
Once on a capacitive screen controller design I had to stick in some pseudo-randomization on the electrode PWM to avoid this coupling. It was a pain in the ass.
Once on a capacitive screen controller design I had to stick in some pseudo-randomization on the electrode PWM to avoid this coupling. It was a pain in the ass.
Just for your information (I am not big fan of the product), but there are battery free (energy harvested) switches which can replace copper runs already.
See for example: https://www.enocean.com/en/enocean_modules_902mhz/
See for example: https://www.enocean.com/en/enocean_modules_902mhz/
I think there is a lot of potential for sending with electric fields. A lot of animals like sharks can basically see using an electric field. It would be amazing if we could replicate that.
I'm imagining a replacement skin that sends touch signals to the brain, so if you've lost an arm you can feel using your prosthesis. I know it wouldn't work for non-living objects, but imagine being able to regain the sensation of human touch.
Didn't Disney present similar technology a few years ago?
"Touché: Enhancing Touch Interaction on Humans, Liquids, and Everyday Objects" [1] and "Botanicus Interacticus: Interactive Plant Technology" [2] used a single electrode and machine-learning classification in order to distinguish between different types of touches and touch locations.
Using multiple measurements (as Electrick does) provides much more robust tracking than these.
[1] http://www.chrisharrison.net/index.php/Research/Touche
[2] https://www.disneyresearch.com/project/botanicus-interacticu...
Using multiple measurements (as Electrick does) provides much more robust tracking than these.
[1] http://www.chrisharrison.net/index.php/Research/Touche
[2] https://www.disneyresearch.com/project/botanicus-interacticu...
Cute, but very low resolution. The paper describes sensing a 4x4 array. Multi-touch is possible, but fingers closer than 10cm can't be resolved. The paper doesn't say anything about ambient humidity. That will affect this approach. So will skin dryness.
It's nice, but not better than existing touchscreen technologies.
It's nice, but not better than existing touchscreen technologies.
You're missing the point. Currently capacitive touch interfaces require a grid of copper and an MCU. This new technique lets you add the interface to any object that will take a thin film spray, which is great! The same issues with false positive rejection from humidity and moisture and radio noise exist, but now we can add it to arbitrary objects like handles and such without busting ourselves integrating the copper loops into whatever device it is we're building. You can just spray the surface, calibrate, and go. Lots of great design space here.
It's better than existing technologies in the sense that you can put it on a vastly wider array of surfaces. This looks like a very early iteration; I expect the technique could be improved upon to yield higher accuracy and support for multiple touches. More electrodes, smarter electrode coordination, better conductor regularity, etc. could probably all help. Even without these things, it already seems quite useful.
Video made it look pretty decent in terms of resolution -- notice the author move his finger around and trace the line. This isn't like 16 points total.
While I agree with you that transparent touch screens are currently underutilized in the sex industry, this technology will enable things beyond your wildest dreams.
I'm sorry if I'm missing something, but did you mean to reply to a different post here? I don't quite see the relevance of what you're saying to anything that the original post covered.
Yes, OP said nothing about sex work.
No, I am replying to the right post.
Can anyone eli5 how it works? I couldn't seem to tell.
How about ELI15? Touching a conductive surface reduces voltage in that area. Place sensors around the perimeter, and rotate the source of voltage to triangulate the location.
Did you watch the video? They explain it fairly well.
Would this be useful for robot touch sensors?