Thread: Tigger Signal

Hello,

currently I´m working with a programm, that is a software to a thermal camera. Its an opensource, so I can change anything I want.

There is an Alarm function, that triggers beeping after reaching some temperature. I have to change this function, so I could get a 5V trigger signal from my pc to some device, that stops heating etc.

I`ve done some research and found out, that might be possible with serial or parallel port. How could I use those in C++? Are there any turorials?

Thx in advance!

But I´m still unsure, whether it is possible to do with usb. As far as I know, there is only constant output, and I need only a trigger.

Originally Posted by Salem

> I`ve done some research and found out, that might be possible with serial or parallel port.
...
> But I´m still unsure, whether it is possible to do with usb.
Well you could decide which interface to use.

If you've got a parallel port, then that's perhaps the simplest option, as there are a few pins where you can directly manipulate the signal level.

You could probably do the same with a serial line, by manipulating CTS/RTS.

USB is different, it is a protocol as well as an electrical interface. You can't just manipulate the signal level as you would want.

FWIW, if you're trying to control something like "turn a heater on and off", which is going to need a lot of power, then perhaps an interface like this is something you should look for.

Eg.
Serial Port Relay Board
There are plenty of suppliers of this kind of kit; check your local electronics shop.

Thx a lot for your reply!

There is surely an option to buy PCI to Parallel port device, that is cheap. So its not a problem.

The thing is, I dont really undestand, how I could manipulate with this parallel port in C++. Are there any tips?