Hello Question on Pro Mini on 4.5v.

Hello i was wondering i have a 3AA battery holder for 4.5v and i i tried it on my Pro mini and it works i was wondering if there would be a problem with not having a full 5v power source on it? I'm driving a Nokia5110 lcd and a Lm35 Temp sensor. I'm making a temptuare sensor display so far i had it on for 3 hours and it's been going no black light on the LCD yet because not sure if it will kill the batteries faster.


You should really use four or five AA batteries (you can use a dummy or dead battery in place of the 6th battery with a shorting wire across it in a 6-battery holder) and use the RAW or Vin input of the Pro-Mini. You can get by with 6V into the RAW/Vin input and that will give you 5V at Vcc. It's not a good idea to run the Pro-Mini on 4.5V because the spec for TTL is 4.85V to 5.25V.

Hello raschemmel thank you for that information I'm only programing it once and that's all i have are 3AA battery holder packs i guess i can do 2 together.

Some reason it's still alive on the 4.5v 3 double AA batteries been on for almost 5 hours now i think it might be okay.

The pro mini is designed to work well on 4.5 V and in fact much lower voltages, although below about 3.5 V, you might run into problems if you use the 16 MHz crystal or resonator.

Do not use the RAW input, instead use Vcc as power input and bypass the on board regulator.

For CPU clock speed versus voltage considerations, see Section 28.3 and Figure 28.1 in the ATmega328 data sheet.

Hello jremington that is what i did put it to vcc so far i got it running and keeps to be working great thanks.