ageedizzleDo smoke detectors have little speakers inside them? If yes, would it be possible to hack them to play a little jingle?
gedaliyahUsually it’s not exactly a speaker, but it does involve a controlled moving diaphragm. In a piezoelectric buzzer, a current applied to the diaphragm causes it to oscillate, and the size and shape of the diaphragm determines the tone AFAIK.
It may be theoretically possible to engineer such a device into a rudimentary speaker. I mean, people have done it with Tesla coils and player pianos, so hey, anything is possible?
CameronDevYou can also make hard drive heads play music. Poor quality music, but music.
Multiple piezoelectric buzzers could probably play a tune if you tune them to individual notes. Not sure how to tune them, but probably cutting them, or putting bluetak on them would alter their note.
Never tried floopy drives, good acoustics?
Have you not seen Flopatron?
Apologies for the YouTube link but I don’t think he posts things anywhere else.
The Floppotron: Rick Astley - Never Gonna Give You Up
Never seen it before, never been so happy getting rickrolled :D
You can also make hard drive heads play music.
How does this work?
A basic speaker is functionally a copper coil next to a permanent magnet. A hard drive head (although I guess more specifically read arm?) is also a copper coil next to a permanent magnet. So if you push an audio signal through the coil, it vibrates and makes sound. It’s missing the diaphram/cone part of the speaker, so it’ll be very tinny.
If you want to make one yourself, get a broken hard drive, and an old pair of headphones, and connect the wires to the coil and play some music.
Hard Drive Speaker - More Instructive Version
Hard Drive Speaker - More Instructive Version: So, you found/scavenged/broke a Hard Drive, and want something more constructive to do with it than make the platters into a wind chime, or just beat the thing to death with a hammer? You've come to the right place! I actually made mine a year or s…
Interesting. I’ve never heard of a piezoelectric buzzer before. This is the answer I was looking for. Thanks!
labdarna.com/…/understanding-piezo-buzzers-how-th…
They use piezo buzzers which work differently to most speakers. I would guess that the units used in smoke alarms and microwaves generally have integrated drivers that only operate at a single frequency. However, it is possible to drive piezo discs at different frequencies. Their ouput will always approximate a sound wave though, so don’t expect to be able to use them like a normal electrodynamic/ voice coil speaker to play arbitrary sounds.
You can if the buzzer signal is only used to trigger a secondary circuit that does what op is looking for.
That’s what I would do. Hook jumpers from the buzzer to the play button of an mp3 player.
That way if the music system fails, the buzzer still wakes you up.
I would guess that the units used in smoke alarms and microwaves generally have integrated drivers that only operate at a single frequency.
Yeah, you could more easily create a rhythm than a full melody. If you get a few devices, which beep at different frequencies each, you could do a lot more by having them beep in succession and in intervals.
Of course, this requires that they’re roughly in tune, which may not be the case at all. 🥴
ChaoticNeutralCzechPiezo buzzers have a resonant frequency they’re strongest at. Two-pin piezo disks need driving at the desired frequency. Three-pin provide a phase-shifted feedback to the driving transistor to keep oscillating at the resonant frequency. Some include that whole circuit inside their housing so they have just 2 pins but those are for DC power, only the volume can be somewhat adjusted by changing the input voltage.
Interesting thank you. The integrated drivers thing would make it difficult to hack but I guess its always possible to crack the smoke alarm and replace the drivers, if someone really wanted to get their hands dirty
I don’t have any answers - but now I wonder if your idea would be easier when working with one of the fancier smoke detectors with voice alerts. Those have pre-recorded voice alerts that “speak” when an alert occurs, rather than beeping. Those pre-recorded messages must be stored somewhere in the smoke detector.
Putting in a request now for the intro noises from Korn’s “Twist.”
Beeps don’t usually come from a speaker, no. You might find this old ELI5 about electronic sound interesting.
Linking to Reddit on Lemmy is blasphemy. (But thanks for the link lol its informative)