Making headway, as this is transmitting screeches at 530 MHz, (but 3.5mm jack input should transmit music, not screeches). I know it's transmitting from phone as when I pause audio, the screeching stops. Since digital pin 9 does not generate screeches, I'm guessing something might be done to tweak PWM voltage from input source? Or should a digital pin be the transmit, and I'm missing something in the code? I'm at an impasse so any tips for moving forward appreciated.
int audioPin = A0; // positive lead from 3.5mm phone headphone jack; other lead to GND
int transmitPin = 6; // positive lead to antenna; neg. antenna lead to GND; tried digital pin 9 also but that doesn't make noise.
int val = 0;
void setup() {
pinMode(transmitPin, OUTPUT);
// set up Timer 1
TCCR1A = _BV (COM1A0); // toggle OC1A on Compare Match, Timer Interrupts
TCCR1B = _BV(WGM12) | _BV(CS10); // CTC (clear timer) no prescaler
OCR1A = 14; // 530 MHz
}
void loop() {
val = analogRead(audioPin);
//digitalWrite(transmitPin, val); pin 9 isn't transmitting screeches as mentioned.
analogWrite(transmitPin, val);
}