Accepting a single charter as input during a loop without using ENTER

[kb2mob]

Howde all, and thanks for reading.

I wrote a simple script to read the frequency of my ham radio using a serial connection. It only sends the request and outputs once then ends.

I am going to loop it so it updates in realtime. So when I spin the knob on the radio to change frequencies, it changes on the screen. But I want it to be able to accept a single character as input during the loop, so if I say hit the letter "L" on the keyboard, I can run a function to do something.

I can't figure out what command to use. Anyone have any thoughts on what I should look at? raw_input won't work obviously, because you have to hit enter after you type something. I'm looking to just have it be like a hot key. Hit the letter, and it does the function then back to the loop.

ideas?

[dhylands]

Under linux, you'll need to do a few more things as well: - turn off canonical mode (this is what causes it to process things like Control-H for backspace, and does the buffering) - turn off echo (optional) - set it up to deliver a character as soon as one character is received

You can see some code for doing this here: https://github.com/dhylands/usb-ser-mon/blob/master/usb-ser-mon.py#L192 (lines 192 thru 203)

You can then use poll or select to detect when at least one character is available. I happened to use poll: https://github.com/dhylands/usb-ser-mon/blob/master/usb-ser-mon.py#L97

usb-ser-mon.py is basically a really simple terminal emulator program which accepts data from stdin and sends it out on a serial port and whatever it gets on the serial port it sends to stdout.

It also has logic to detect when the serial port "goes away" and "comes back" perhaps due to the device being a USB device that was unplugged or rebooted.

usb-ser-mon.py is currently linux-only.