I have this little AtTiny45 which I'm loading a program with Arduino as ISP.

My goal to use this chip along with a op amp, a piezo buzzer and a press button, and have it automatically sleep between uses.

I intend to use 2 3V pill batteries in parallel (specifically CR2032 if this makes a difference) as the power source, so here are my two questions:

  • Can 2 3V pill batteries in parallel power a small application that will produce audible sound?
  • How long could these batteries last --based on constant use-- if someone used this item for an hour per day?
  • Thanks jsotola! I've updated the question to fit more the need as I was not as clear as necessary. It has a press button which will spark a sound for a short while then resume sleep.
    – B7th
    Oct 8, 2020 at 6:13
  • Everything depends on used parts, and overall current consumption... For now it's just "it might or it might not" to almost every question you have
    – KIIV
    Oct 8, 2020 at 14:57
  • 1
    Assuming 5mA when on, one hour a day; 2µA when sleeping the rest of the time; I get around 40 days of runtime. But you can probably have the MCU sleep in between task during that 1 hour of usage. You might have to find a way to turn of the opamp when it's not needed, to keep the sleep current as low as possible. I'm unsure how much current a piezo uses, but I don't think it's much.
    – Gerben
    Oct 8, 2020 at 16:09
  • I guess one could provide current to an opamp through a transistor?
    – B7th
    Oct 8, 2020 at 18:52
  • @Gerben I followed the link very useful! Thank you
    – B7th
    Oct 9, 2020 at 7:59


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