[Dimitris Platis] wanted to add gesture control to his PC. You’d think that would be expensive, but by combining a diminutive Arduino, a breakout board with a gesture controller, and an interconnect PCB, he managed to pull it off for about $7. That doesn’t include the optional 3D-printed case and we think you could omit the interconnect board if you don’t mind some wires and further cut costs. [Dimitris] calls it Nevma, and you can see how the device works in the video below.
The heart of the project is a sensor that measures light and motion. The chip and the breakout board are just a couple of bucks if you order them from China. You can find them in the US if you don’t mind spending a little bit more. The device has an I2C interface, and [Dimitris] uses a tiny Mini SS Micro for the USB interface and the CPU.
The sensor chip is made for the mobile phone market and can also sense proximity. From its data sheet:
Gesture detection utilizes four directional photodiodes to sense reflected IR energy… The architecture of the the gesture engine features automatic activation (based on proximity engine results), ambient light subtraction, cross-talk cancellation, dual 8-bit data converters, power saving inter-conversion delay, 32-dataset FIFO, and interrupt-driven I2C communications.
That seems like a lot of power for a few bucks. Sparkfun has a library (and a matching board) and [Dimitris] uses it. The library is released as beerware. In particular, the documentation says: “The code is beerware; if you see me (or any other SparkFun employee) at the local, and you’ve found our code helpful, please buy us a round!”
We really like Nevma. You don’t have to hold any device in your hand. It also looks slicker than the solutions we’ve seen (and even created) using SONAR.
There is actually a smarter and cheaper way to do almost the same thing:
https://danielrapp.github.io/doppler/
It’s using doppler effect on top of a sound that not audible by human ears… Very smart since it’s use the mic and the speaker from the computer that are already there (hence free).
20kHz is most definitely audible, and painfully so, for lots of people under 25. That application is also highly dependent on mic and speaker placement for tuning, which well change your results dramatically. This sensor is small enough to be integrated into the top of a laptop to provide smart gesture control without the nasty high pitch whine.
luckily most modern sound cards with sampling rates up to or over 96kHz will easily do 40kHz too, good luck hearing that.
Good luck finding speakers to reproduce that with any sort of accuracy.
https://github.com/mistic100/three.js-examples/blob/master/LICENSE
i see no license text on your site, not even in the source files
Thanks for looking. It’s actually not really supposed to be public — the license text isn’t even loaded onto the server, mostly by accident. That being said, it’s getting changed out in a few days.
Sorry if I trampled anything, it’s not intentional. Also, isn’t it Doob?
What I have heard from audiologists is that is ultrasonics can cause hearing damage just as bad as at audible high frequencies. The Cuban diplomatic visits with suspected sound attacks are being investigated. Your pets may not like it. Though it’s a good way to boot squirrels in your attic.
To ultrasound or not. That is the question facing women as there is no complete distinction between an ultrasound and ultrasonic cleaning especially in developing brain tissue.
This sensor would be a lot of fun in sound control environments.
Yep! It’s a great way to keep millennials from hang out in this old fart’s office.
$7 is actually about right for something which is so pointless.
The only use is when you have it in the kitchen or something and you don’t want to touch anything. Although I can’t say I ever needed a computer in the kitchen.
Still, it’s nice it’s available to build for a low cost in case someone finds a use. So thanks Dimitris.
Kitchen computers are nice for unit conversion, music, recipes etc. Actually only place in the house that voice control seems worthwhile for me.
As you say, people seem to go for Alexa type stuff in the kitchen with voice activation.
I agree. The application presented in the video doesn’t at all highlight what it might actually be good for. The effort needed to do something as simple as scrolling, starting stopping music etc with this device is much more than if you would just press a button your keyboard. However, using this when you don’t have keyboard, that might actually be useful.
It could be interesting to code a theremin application for that.
I just bought a few of these. The plan is to connect it to an esp8266 and try to get this working:
https://www.forbes.com/sites/kevinmurnane/2017/08/09/augmented-reality-technology-a-student-creates-the-closest-thing-yet-to-a-magic-ring/#77bd01e53eaa
NICE
I bought these boards and used them to add gesture control to my desk fan. I am the envy of two coworkers.