Momentary Pushbutton

This forum my not be the best place to ask this. But, it is the best I can find. Does anyone know of a device that will allow me to use a USB or Serial Port to press a Momentary Pushbutton?

I just want to be able to click a button on my screen and have it send a signal to a device as if I was pressing a physical button.

Thanks for any help

The short answer is yes. The longer answer is it depends on how you want to do it. For the short answer, look for a USB or serial relay board. They’re out there.

The longer answer is that pretty much any microcontroller that has digital I/O can do this with some extra hardware. What that extra hardware is depends on what kind of load you want to switch.

For AC mains, Crydom, Teledyne, Opto-22, and others make TTL input, 110V or 220V (or 440V, or higher) solid state relays. I use two Crydom relays to switch 110V AC to control the spindle and coolant pump on a mill. Dead-easy to use.

For smaller loads you can just use a transistor to do the switching. There should be lots of examples for how to do this out there on the web. If not I can come up with one to post here.

It’s the USB or serial end that is actually more complicated, and it’s not that much more complicated. You need to pick a micro that can talk to USB or serial. Which is pretty much most of them considering you can get an RS-232 level shifter or a USB to serial adapter from Pololu.

So if you’re looking for a single device, the USB or serial relay board may be your best bet. If you don’t mind building circuits, one of the USB or serial converters, a microprocessor, and the switching hardware, and you’re good to go.