Pushbutton power switch

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi,

I need a circuit for my project that powers on the arduino by the press of a pushbutton. Subsequent pushes to the same button should be picked up by the arduino.

I want to switch off the power with a pin on the arduino.

I know the pololu pushbutton power switch and that's almost what I need, but without the off-function of the pushbutton.

I have some pnp and npn transistors and some n-channel mosfets, would be nice if I could use these.

Have a nice day,
Rick

2

It looks like what you want is a latching relay. This has two coils, one to turn it on and the other to turn it off.
You need too arrange your power button to activate the relay and be fed into the arduino. That way when the arduino is on you can read it being pressed. Then an arduino output goes through a transistor to pulse the off coil.

3

Thanks, I'll try that - I was going for a solid state solution, but a relay may be even better because that way it'll use no power at all when the circuit is off.

4

Thanks, I'm going to use this solution for something similar. Thanks Grumpy Mike and Rick P

5

I ended up using a latch relay on my reverse geocache (See exhibition forum). Works great - I used the Panasonic TQ2SA-L2-5V. A button switches the power on and the arduino can switch itself completely off.

6

ahk, Yeah I saw that. Really good job with that.