Arduino pro mini battery option

Hi,

I have a Arduino Pro mini 328 - 5V/16MHz. I currently have six DS18B20 sensors and the communication is made via a HC-05 Bluetooth module.

I am powering it via a basic Alcaline 9V 6LR61 but this battery is too big but the battery life is good.

I would like to know what are the best possibility for having a thinner and rechargeable battery like a Lithium Ion ? The 6LR61 are now too big for me, same for AA(A), it would need to be in a restricted area.

I assume I need to have a battery >= 5V but I only find 3.7V

Thanks !

Boyduino: I assume I need to have a battery >= 5V but I only find 3.7V

Why would you assume that? You can get 3.3 V/ 8 MHz Pro Minis; so which other components require 5 V rather than 3.3 (3.7) V?

On my HC-05 it is written
Power : 3.6V - 6V

My bad, I was assuming it was at least 5V.

But a battery of 3.7V is enough to power the HC-05 and all other stuffs ?
The problem is I have only Arduino pro 5V :confused:
Small battery doesn’t exist in 5V or more (< 12V) like the 3.7V ones ?

Thanks

Boyduino: I am powering it via a basic Alcaline 9V 6LR61 but this battery is too big but the battery life is good.

Did you mean good or no good? The reference for teh best version suggests 400 mAH at 100 mA, or about 4 hours life.

Boyduino: On my HC-05 it is written Power : 3.6V - 6V My bad, I was assuming it was at least 5V.

Most of these devices are actually 3.3 V or thereabouts.

Boyduino: The problem is I have only Arduino pro 5V

Well it will involve some delay, but Pro Mini 3.3 V/ 8 MHz are really cheap on eBay.

Hi Paul

I meant good battery life, no problem with that. But too big :slight_smile:

If I can I prefer to stick with the Arduino pro mini 5V as long as possible but if you tell me I will have difficulty to find a suitable battery I will think about switching quicker than I originally thought.

Not sure if it helps but I've run a 5V pro mini off 3xAAA cells (about 4.5 volts) without any issues.

There is also this thread which has some info

Thanks rw950431 but I would prefer a thinner battery.

The thread seems to suggest that you can run a 5v arduino on a lower voltage if you underclock it a bit. Havent tried it myself

rw950431: The thread seems to suggest that you can run a 5v arduino on a lower voltage if you underclock it a bit. Haven't tried it myself

And there's the point. How do you "underclock" it?

(And have working serial communications ...)

So I just put a battery (3.7V) from an old Samsung phone (not smartphone). The wiring is not easy because I don't have the appropriate connector but it seems to work on my setup so far even with a 5V Arduino and a serial connection over bluetooth. I don't know about the range yet but that is good enough for now