Easiest way to interface with 3V garage door remot

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi - I didn't see an Arduino for dummies forum, or I would have posted there :wink:

I have a simple run of the mill radio garage door opener, it runs on a 3v battery. What is the easiest way to wire it up to an Arduino?

The obvious way seems to be a relay switch, and I see the instructions on how to do that.

But I wonder if I even need one - can I just wire a digital pin and ground in place of the batter, short the button, and supply the power directly from the digital pin? It's very low current.

Auxiliary question from a software guy trying to do hardware - why does my multimeter ready like 2.3v when I put it between any digital pin and the ground? And when I set the pin to HIGH the multimeter doesn't budge.

Thanks!

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But I wonder if I even need one - can I just wire a digital pin and ground in place of the batter, short the button, and supply the power directly from the digital pin?

Which Arduino are you using? One that runs on 5V is very likely going to damage your 3V garage door opener.

It's very low current.

Less than 40ma? (which is too much) Even when transmitting?

Auxiliary question from a software guy trying to do hardware - why does my multimeter ready like 2.3v when I put it between any digital pin and the ground?

You've set a pin to OUTPUT and it reads 2.3V when it's LOW and HIGH?

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A long time ago I used a transistor and resistor to operate the "up" button on my tv remote control (below).

http://web.comporium.net/~shb/irmods.htm

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Do you mean when you have the garage door opener hooked to your arduino it outputs 2.3V regardless?

Have you set the pin to output with pinMode(pin, OUTPUT)?

It also helps if you can measure the current when you operate the garage door with the battery, if you can manage to do that.