I'm working on a project whereby I want to use the Pi to send some morse code (CW) over FM by feeding the CW signal into the mic input of a handheld radio I've stripped down.
The idea stems from this website where the chap is using a PIC based solution to generate some hard coded CW and feed into the mic input of the rig. I built one of these and downloaded his code and it works great.
Instead of using a PIC, can I use the Pi? I have some basic code to send logical 1's and 0's to the GPIO pin, actually the code I've doctored from various sites detailing how to send RTTY in C, but essentially its about switching the pin on / off at the right times. I dont get how the PIC itself generates audio. When i've tried putting the GPIO pin connected to the mic input, I'm not getting anything. I didnt really expect to, but I cant even make out any discernable changes in voltage.
Am I barking up the wrong tree? Any pointers appreciated.