Smallest recharable power option

Discussion in 'General Electronics Chat' started by stoopkid, Mar 13, 2012.

  1. stoopkid

    Thread Starter Member

    Mar 3, 2011
    I'm working on a small project(hopefully small enough to fit in a necklace locket) that consists of a atmega85(using about 2mA) and one RGB LED(that I will probably try to get under 20 or 30mA for all three colors). A couple of stacked cr2032's would work but it would be really nice if I didn't have to burn through them. I'm looking at rechargeable 2032's but I figured instead of conforming to a standard size, I should be looking for best capacity/size.

    So im looking for as small as possible, flat being a priority, and getting as close to 5v as I can.

  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    A tiny lithium ion will yield 4.7V.
  3. MrChips


    Oct 2, 2009
    I can only assume that you are attempting to create some kind of wearable device with LEDs. Your objective should be to keep the power consumption down to a minimum. Here is what I would do.

    1. There are MCUs that consume very low power, in the micro-amp ranges.

    2. Operate the LED and maybe even the MCU in a pulsed mode, sleep/wakeup in order to reduce the current drain.

    3. Operate off a single 3V coin battery. This will simplify the physical assembly.

    4. Use high efficiency LEDs that operate with less than 1mA.