Arduino uno as an oscilator

[yossi1ard]

Has anyone built a 20000HZ oscilator with the aeduino uno ?
I'll happy to about it/
I am planning to use it for distirbing bats to fly around my home,
Thanks,
Jossef

[anon73444976]

20kHz is simple, but it is often illegal to disturb bats.

[lastchancename]

…and a bit of overkill if nothing else is being explored..

Next challenge is the amplifiers and transducers.

[DVDdoug]

The tone() function will do it.

But you could use an LM555 or something similar. It's cheaper.

If you haven't do so already, try generating a high frequency tone with Audacity on your computer to make sure the concept works for you.

[CrossRoads]

Simple code for a test:

byte triggerOut = 19;

unsigned long currentMicros;
unsigned long nextMicros;
unsigned long duration = 25UL; // flip every 50uS = 20KHz pulse
unsigned long elapsedMicros;

void setup() {
  pinMode (triggerOut, OUTPUT);
}
void loop() {
  while (1) {
    currentMicros = micros();
    elapsedMicros = currentMicros - nextMicros;
    if (elapsedMicros >= duration) {
      nextMicros = nextMicros + duration;
      PINC = 0b00100000; // toggle D19 output by writing it input port.
    }
  }
}

On a 'scope, will have a little jitter from the micros()/millis() interrput.

[vishkas]

Yeah It works, simple and straightforward work

[johnerrington]

There are several issues with this notion;
1: many bats use ultrasound to echolocate; you MAY think that its a good idea to use ultrasound to influence their behaviour. However bats are LOUD. You would need a LOT of sound to have an effect.
2: producing that would require an amplifier and transducer capable of generating sound in that region; maybe a set of supertweeters, or a (VERY EXPENSIVE) ultrasound loudspeaker.
3: A fixed sound would not be enough - it would need to vary or the bats can just ignore it.
4: You would get complaints from . . neighbours with small children (I could hear 24kHZ well into my twenties) ; or with pets (dogs have good hearing).
5; you might attract rodents
6; only certain bats echolocate.

[vishkas]

Yes great information related to that...