Quote:
Originally Posted by Andrew2
A while ago I built a subsonic detector.... It makes ghostly piping sounds .... it annoys the heck out of my wife!
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Andrew,
Thanks!
My equivalent of your ultrasonic set-up was a small box (powered by a lithium cell) and a 40106-based circuit arranged to beep about 10 times every 3 minutes or so. I really built it to explore the low current consumption of the 40106 (6 schmitt gates in one chip). I ended up putting it on top of the glass cabinet in the dining room (which was largely only used for visitors). One of my wife's visitors commented that we seemed to have a lot of lorries reversing near the house, which she couln't understand, because she didn't see any.....
dave