Gimzo 2 custom On/Off button?

Check out this post where I added an external power and reset button: http://www.element14.com/community/community/designcenter/single-board-computers/gizmo2/blog/2015/01/28/gizmo2-adding-external-pwr-and-rst-buttons

Oh wow, so much great tutorials I'm having hard time finding

So you didn't use a resistor?

Is there any requirement for what button can be used. All I know is buttons have a maximum current rating, this shows how little my electronics knowledge is. But it's going to be fun programming the Gizmo after I get this figured out.

PS. Is that a 3d printed enclosure? That's another hobby of mine.

You mean that you have a relay driven by 12V? If so, and you can't use / find the transistor you should find a relay driven at 5V else when you power it for switching nothing happens.

Enrico

Yes, it seems I need a 5v relay shield for Arduino to use a relay.

Arduino+relay is getting complicated option itself.

Maybe it will be easier to jut use the transistor with the arduino after all.

It's just two thing I don't get: how would I find out the ground side of the button of the projector? Voltmeter and checking if it shows positive or negative voltage?

If the projector and arduino have a common ground, isn't it dangerous if one uses more current then the other can handle? (Arduino has 5 buttons connected and controls a servo motor). Or is connecting more stuff to GND not dangerous.

how would I find out the ground side of the button of the projector?

Just check with the voltmeter and see where is the negative it's the GND. On Gizmo2 schematics are distributed for free and are very helpful to find also where ground pins are on the board connectors.

No matter about GND, all ground should be connected. voltage does not interfere at all, if you connect things correctly.

I know about Gizmo, the video projectors ground is not known thats why I asked.

I supposed, so you should check with a voltmeter the negative should be GND

Will do and report back.

Ok.

Oh forgot this. The GND from the Arduino is 5V, from projector its 12V. Is that an issue?

I understand, no offence taken. However, most of this is electronics, not electricity. You now mentioned diodes for return current protection, I didn't know about them. So if GND taking 12V and 5V wasn't a problem for the respective devices that wouldn't be needed, right?

I understand, no offence taken. However, most of this is electronics, not electricity. You now mentioned diodes for return current protection, I didn't know about them. So if GND taking 12V and 5V wasn't a problem for the respective devices that wouldn't be needed, right?

It is the worth to use diodes, in my opinion