Bat detector page
Main homepage
mail me !
|
Calibrating your bat detector
Some ways to generate ultrasonic tones and noises:
- PAL 50 Hz TV's generate ultrasonic tones at the horizontal line frequency of 15625 Hz
and multiples of that (31250 Hz, 45875 Hz, 62500 Hz etc.).
- Many digital watches use a 32768 Hz crystal,
that you can hear if you hold the watch really close to the bat detector microphone.
- Rubbing your fingers generates ultrasonic noise up to about 60 kHz.
- Handling a wrinkly plastic lunchbag also produces lots of broadband ultrasonic noise.
- The sounds coming from rattling a bunch of keys are converted to metallic sounds by a bat detector.
Calibration software
- USonic,
a freeware MS-DOS based utility for generating ultrasonic tones using the PC's built-in speaker.
Written bij Joost Ruijsch.
- My own 'Calibration' program (screenshot),
a utility for generating ultrasonic tones on a Palm handheld computer (or compatible).
|
