AA powered Pro Mini

I've been reading a bit about powering projects with AA batteries. I plan to do a wireless temperature sensor thingy.

I'm trying to decide how to power the project as all the components have different voltage specs. Pro Mini, NRF24L01 and DS18B20.

I was thinking of running iit off 3AA batteries but that goes over the allowed voltage for the radio so thought I could take two lines from the battery pack, one from 2 batteries for the radio and Arduino and one using 3 for the temp sensor.

Does this sound like a good idea?

ChrisHigs: I was thinking of running iit off 3AA batteries but that goes over the allowed voltage for the radio ...

U can get 3.3V supply from the Pro Mini for the radio.

This forum thread shows how to hack the Pro Mini to run efficiently on 3V batteries: http://forum.arduino.cc/index.php?topic=226261.0 In particular see posts #6 and #10.

Be sure to reduce the power demand as much as possible, by carefully studying this very informative article: http://www.gammon.com.au/power

FWIW if u did want to run the Pro Mini at 3V - u could buy a 3V version.

aisc: U can get 3.3V supply from the Pro Mini for the radio.

I was trying to avoid using the regulator to increase battery life.

jremington: This forum thread shows how to hack the Pro Mini to run efficiently on 3V batteries: http://forum.arduino.cc/index.php?topic=226261.0 In particular see posts #6 and #10.

Be sure to reduce the power demand as much as possible, by carefully studying this very informative article: http://www.gammon.com.au/power

Thanks. I'll have a look at those.

aisc: FWIW if u did want to run the Pro Mini at 3V - u could buy a 3V version.

I've got a few of the 3.3V minis. My concern is keeping the voltage under 3.6V for the radio and above 3V for the temp sensor.

I have a similar project using 5V Mini Pro + 5V sensor + 3.3V RF. My workaround for the prototype (since I have the real estate) is to use 2 sets of batteries. - 3xAAA for the Arduino and Sensor - 1x3V coin cell for RF

Just thinking outside the box :)

aisc: I have a similar project using 5V Mini Pro + 5V sensor + 3.3V RF. My workaround for the prototype (since I have the real estate) is to use 2 sets of batteries. - 3xAAA for the Arduino and Sensor - 1x3V coin cell for RF

Just thinking outside the box :)

In was thinking of doing a similar thing but instead of having 2 different battery packs just taking two lines off the same battery pack with the two different voltages. Not sure if this is a good idea or not.

But yeah, i could do the same with one 2 and one 3 battery pack.

One thing to remember is the Arduino outputs will be at 5V - so u cannot connect an Arduino output direct to an RF input. You will need to drop the voltage.

aisc: One thing to remember is the Arduino outputs will be at 5V - so u cannot connect an Arduino output direct to an RF input. You will need to drop the voltage.

I'll be using a 3.3V device so I won't get 5V on the outputs. But the nRF24L01 can handle up to 5V on the data inputs.

Well I've got a test unit running outside now. Pretty cold out there currently 5 degrees.

I've used 4 NiMH batteries. 2 to the radio (3 started at 4V fully charged), 3 for the Mini and all 4 for the sensor. it will be interesting to see how well this works and how long it lasts.