Proud owner of some new netduino2 cards for my project.
I am building an IR-motion detection system. Each system consists of one netduino2, an IR-sensor and an a very cheap off the shelf FM-radio (walki-talki). I have the IR-sensor nailed I think, however I am kind of struggling with connecting the netduino to the FM-radio. The goal is to have several systems that communicate through the FM-radio using DTMF-tones. I have built my own "packet/protocol" that I will use when I send packets. WI-FI is not an option as i need range (mote than 1000m).
The FM-radio have a microphone. I need the netduino to send "DTMF-tones" to the microphone. The microphone have to pins (grd and +). I guess I should remove the mic on the radio to remove background noise, however can I connect the netduino to the radio and create DTMF-tones? I have started to look in to PWM, however I cannot find any examples of anyone doing DTMF-tones. Any help would be most welcome.