Add Gestures and Touch to your Arduino | Hacker News Reader

Add Gestures and Touch to your Arduino

justhover.com

29 pointsemranemran11 comments

We created this dev-kit to let Arduino projects work with gestures + touch. It came out of the need for a project which required basic hand gestures to work accurately. We tested with proximity and distance-IR sensors but wasn't satisfied with the accuracy and development time required to make it work. We decided to build a dev-kit that uses e-field distortion to detect gestures accurately. We just launched it hoping it might help other hardware hackers looking to add gestures/touch to their projects.

Any chance you'll release how you built this?

looks like its basically just the reference implementation of the MGC3130 chip, with an arduino library for i2c communication.

Great input device! Very cool work.

Uses the MGC3130:

https://www.youtube.com/watch?v=eclJ1mOFZZg

http://ww1.microchip.com/downloads/en/DeviceDoc/40001667C.pd...

Anyone from the project here care to elaborate on the niceties of this dedicated chip? I'm currently putting finishing touches on a project with a swipe-based (touch, not hover) interface built around the (surely rough-and-dirty, but surprisingly capable) CapacitiveSensor Arduino library.

I'm sure the timing issues one sidesteps by using a dedicated controller ic are critical for projects more complicated than mine, but I'm curious if you know more about the limitations of trying to implement something similar onboard with the AVR. Is there something fundamentally different in the sensing method here compared to low-threshold capacitive sensing?

One of the project owners here. I've used the capsense arduino library a long time ago and it's decent when you don't need the accuracy. I found that the sensor values were affected by the environment quite a bit e.x. I'd have to recalibrate everything if the project was being used in a room with a carpet which affected the body charge. Maybe you found a way around it?

Re: the sensing method, they're similar in the sense that both the avr and mgc3130 detects a change in capacitance to figure out the position. But the mgc3130 controller can detect capacitance changes in the femtofarad range.

Uses GPIO: So not just Arduinos!

I know this mentions it in the description, but I think it could be made more clear. Sincerely, Order #0039

Thanks for the support and you're correct! We're working on getting rpi integration as well.

Neat. How does the hovering work? Is that also using capacitive sensing?

The capacitive electrodes form an electric field around the surface of the pcb. When your hand or finger (conductive surface) is in range, the chip senses the distortion of the e-field (change in capacitance) to track your hand movement and calculate the position.

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