Guru
Joined: 31/07/2019
Location: AustraliaPosts: 701
| Posted: 12:26pm 30 Nov 2025 |
Years ago my parents had a "ding dong" doorbell. As a kid I opened it up, it had
two metal bars to produce the "ding" and "dong" and a striker on a spring. When the button switch was pressed, a solenoid pulled the striker which hit one bar. When the button was released, the solenoid was de-energised and the spring retracted the striker the opposite way and the inertia made it hit the other bar. It ran on two "D" cells and the push button, the batteries didn't last long which caused a few problems
PS (ed) lately I tried square aluminium tubing 2.5cm ..the idea was based on what I I had read, that even-harmonics add to a sine shape and sound ok, and odd-harmonics add to create a square or triangular waveform which sounds harsh or sharp. So just for a bit of fun I tried the tubing that I had. If it is supported at the halfway point and is struck at about a quarter of the length is sounds quite mellow, but if I hold it at approx a third of its length and hit at the other third point, it sounds quite sharp and doesn't ring for long.
Edited 2025-11-30 22:49 by zeitfest