Doubts with power supply - Arduino Pro Mini

Hi there!

Let me say hello to everybody here before I start explaining my doubts!

Here we go, I'm currently making an Arduino project with a HC-06 Bluetooth module, 2 LEDs, a Pulse Sensor and an Arduino Pro Mini. My problem is that I really don't know what's the best power supply for this circuit. I was wondering if I connect a pair of CR2032 batteries would be the best way, but I don't know really. Circuit is 3.3v, and each CR2032 battery gives 3v, so I don't know if I can use the circuit with those batteries.

What do you recommend me? I need a power supply small and lighter.

Thanks a lot.

Hi, I'm no expert but I think the minute you include Bluetooth you throw the possibility of using CR2032 buttons out the window. The Bluetooth is a transmitter/receiver unit and it will consume more than the 2032 can supply.

Tom..... :)

You will need to measure your current consumption.

CR2032 cells are only recommended for draws of a handful of mA ea. Even 10mA will reduce the usable capacity by 30-40%.

AA cells at minimum. Three alkaline AA. Not AAA, not CR2032. Never a PP3. :grinning:

{Did I say three? If (part of) it will work on 2.8V, then it can be supplied by two or "tapped off" at two, otherwise you may have to provide some regulation. Note that you can "tap off" part of a series of non-rechargeable batteries because you replace them all when any are exhausted.}

LiFePO4 cells give 3.2V nominal, 3.6 fully charged and are worth considering. Alas a particular charger is needed for them (standard LiPo charger should NOT be used). LiFePO4 chemistry is much safer than LiPo and nearly as energy dense.

However if using rechargables you have to prevent overdischarge or you simply cripple the cells.

Thanks to everybody. I will see LifePo4 batteries and check if they are valid for my project. The thing is I need the lightest and smallest batteries for this circuit because I need them to fit in a wristband.

Thanks a lot again!