Easy Touch + Proximity sensing with MTCH101

Maybe everyone else has already sorted this out themselves already, but I just recently wanted a touch switch, and was looking around for a way to do that. I started out looking for simple circuits to do it... and then stumbled on a part that pretty much does all the work.

MTCH101 - SOT-23-6, with one touch channel (sensitivity adjustable with an analog voltage) and an open drain output. Also has a low power mode. I am using a board I bought a while ago (man, someone made some money off me, that chip costs practically nothing!) that I finally found which uses one, and it's delightful. I've ordered some, and plan to test whether they can be made to work under less optimal board layouts. It would be awesome if they could be plunked down onto the original Espruino board's prototyping area, or my protoboard.

I'll be getting them late next week, along with some CY8CMBR3002's, which are a 2-channel cap sensor.

Looks interesting - much easier to wire up than other devices. I'd be really interested to see how you get on. I just found an eagle part for the Nokia 5110 display (without break out), and it would be great if we could make a board that did capacitive touch through the LCD itself. Not sure if that's actually possible though.

I think it's possible to do cap touch with Espruino itself, but it requires some different setup of the hardware timers which means it's a peek/poke job at the moment :(

This module has recently been added too: http://www.espruino.com/CAP1188

CAP1188 looks like an 8 channel sensor, so while it's a pain to wire up it could be quite useful.

So I got my CY8CMBR3002's from digikey.

The "Description" field on the label has me puzzled though: "STREETFIGHTER 8-SOIC"

I've got a few MTCH101 easy touch and proximity sensor boards for sale on Tindie now:

https://www.tindie.com/products/DrAzzy/e­asy-touchproximity-sensor/

Open drain output, adjustable sensitivity, with internal pullup, so you can use it as a standalone switch, or as an input to an Espruino. Operates from 2-5v.

That looks really neat! I've seen some sensors used for plant moisture monitoring... Do you think that's work here? Just a wire into the plant pot, and tweak the potentiometer...

I've made a few ready to use touch sensor boards and put them up for sale on tindie.

https://www.tindie.com/products/DrAzzy/e­asy-touchproximity-sensor/

These can be used like a normal switch, with or without a microcontroller, and feature adjustable sensitivity, and work at both 3.3 and 5v.