#define ledpin 13
//Maybe you will have to experiment also with this value
int bitlen = 5;
-int d, i;
+int d;
+float i;
void setup() {
pinMode(ledpin, OUTPUT);
for(d=1000/100;d<=1000/20;d++) { // 1000/frequency in kHz
//You maybe have to experiment with ^^^ this ^^^ values
//Frequency sweeping: 100->20 kHz works, i saw 60->1 too
- for(i=0;i<bitlen;i++) {
+ for(i=0;i<bitlen;i+=0.5) {
digitalWrite(ledpin, HIGH); delayMicroseconds(d/2);
digitalWrite(ledpin, LOW ); delayMicroseconds(d/2);
}