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Windows7ge
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Thought I'd share this because I like the idea. You know how mini-redundant server power supplies have a little piezoelectric speaker in them that tells you when a PSU fails? Well, I have a project in the near future that could use such feature but for a non-redundant pair of PSU's (considering how expensive redundant ones are this is much cheaper). So I have this:

IMAG0480.thumb.jpg.e7ef35d387e33915b9b7a1e114da1c89.jpg

The idea here is the battery would be kept charged by the TP4056 fed by the PSU 5V rail, the relay would be wired in a NC config and be held high (open) by the 5V rail of the PSU. If the PSU were to lose power the relay would switch shorting the connection allowing power to flow to the DC-DC 5V OUT which would in turn drive the piezoelectric speaker (your indicator that the PSU failed).

 

I realized that if I'm to use two ATX PSUs I could use a pair of relays and wire them up in such a way that each powers the opposing units piezoelectric speaker. This would eliminate the battery and make it so it keeps beeping forever.

 

Unfortunately I just discovered this speaker can't be driven by any normal 5V. It doesn't resonate the drum so to speak. Skanky Sylveon do you know of any small easily driven speakers like this?

  1. Skanky Sylveon

    Skanky Sylveon

    How much voltage does it need?

  2. Windows7ge

    Windows7ge

    This is just a little piezo off a motherboard. I think it only uses 5V. I tried feeding it 5V but all you hear it do is flex one way then flex back when you remove power. I'd rather not dump 12V into it because I don't think it runs on it and I don't want to burn it out. I have no spares.

  3. Skanky Sylveon

    Skanky Sylveon

    Sorry for the late reply. 

    I think some headphone drivers will work at 5v, but I'm not entirely sure.  I don't work much with audio in that realm.  Especially because I'm sensitive to high pitched noises, so I usually try to have a visual warning if possible. 

  4. Windows7ge

    Windows7ge

    Ah, I'll keep looking around. My usual cheapo Chinese electronics site seems to have quite the assortment of options for buzzers/speakers. The application this is for and for where I plan to keep it a audible warning mechanism is really necessary. I can add an LED in parallel with the output of the relay. If it's on the PSU is good, if it's off the PSU has failed but I do need it to make a noise. 

  5. Skanky Sylveon

    Skanky Sylveon

    If you could hook an amplifier between the two, you could power just about anything, but that may be unrealistic. 

  6. Windows7ge

    Windows7ge

    Yeah, I need this to be tiny. It needs to fit in a PCI_e slot and take up no more than 2 slots. The buzzer would be ideal but now I''m wondering if mine is just broken or if it needs something special to drive it.

  7. Skanky Sylveon

    Skanky Sylveon

    If I had some beepers I would do a few tests, but like I said, I hate them so I don't have any. 

  8. Windows7ge

    Windows7ge

    Yeah they're not fun but they're great for getting your attention when something goes wrong.

  9. Skanky Sylveon

    Skanky Sylveon

    Or for pissing off cats.

  10. Windows7ge

    Windows7ge

    That's another application I suppose XD.

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