SparkFun Capacitive Touch Breakout - AT42QT1010 questions

Does this breakout have to be hooked to a controller of some sort or can i use it directly in line to momentarily trigger a relay that will power a solenoid that opens my car doors? Also how thick of glass can it go behind? Would automotive glass be to thick? I basically want to recreate this kit that is no longer available.


Thanks,

Jesse Wilson

You don’t need a controller, but the output from this is tiny and won’t be able to drive a relay so you’d need a transistor or MOSFET to boost things.

As far as working through automotive glass, I don’t think that would work because of how thick the glass is, but if you stuck a large enough electrode on the inside glass it might. (You’d have to try it and see.)

The kit that was available had a clear adhesive strip that was touch sensitive and you could put it on the surface of the car and use it. Is there something like that i could use? There are videos on YouTube of the kit installed if you look up autoloc ultratouch

Sorry, we don’t carry anything like that.

What voltage and amps does it take to trigger a 40 amp relay? My glass is 3-5mm thick, i watched a video of one of these switches behind 6mm wood and worked fine. I want to increase my sensor area with foil tape behind the glass and connect to the pad pin on the board.

I found this online and they say any switch with 1a or more can trigger a 40a relay with power to spare.

TS-CHRIS could you point me to what i would need for a mosfet and some kind of schematic to achieve what I’m trying to do? I think I’m going to get 2 of these sensor breakouts.

What voltage and amps does it take to trigger a 40 amp relay?

Depends on the relay, some need hundreds of volts to trigger others only need 12, the spec sheet for your relay should have this information. The AT42QT1010 can only output 0.002A and any relay you find is going to need more than that.

could you point me to what i would need for a mosfet and some kind of schematic to achieve what I’m trying to do?

Unfortunately I don’t have a schematic for you but it might be easier to use a kit that has a relay and MOSFET/transistor already on it. The Beefcake Relay can be controlled from the AT42QT1010 and that could turn on your 40 amp relay. You’d connect the output from the AT42 to the control input of the Beefcake and then connect your larger relay to the Beefcake’s output.

can i make this a momentary switch instead of an on/off switch? I bought 2 of these and they work through my car window but i need momentary for what I’m trying to do.

https://www.ebay.com/itm/DC-3V-18V-5V-1 … .l4275.c10

Unfortunately we don’t carry that product and I have no idea how it works. You might try contacting the seller to see if it can be changed to a momentary switch.