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How to run my atmega 328 chip from 4 AAA batteries?

Former Member

Hello,

 

Im currently working on my first real noobish project, its a temp/moisture sensor for my brother for his organic garden,

i have all my leds and 330 resitors soldered on, but i need to know waht componets i need to take 4 AAA batteries and power my chip without the Arduino,

everything can fit into the container i want it in (an altoid can) but i need to know what resistors/capactors or regukaters i need ino order to safely run my hardware.

 

also what ways can i use my multimeter so i can measure the volts and amps, so i can calculate how long the batteries would power the device.

I hear alot of great things about the element 14 community and i cant wait to hear what you guys have to say image

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  • 0

    I just know im going to get flamed by my community fellows for this but the simplest way of powering the whole thing from the batteries would be to simply put a couple of diodes in series with the battery, thereby dropping the voltage by 0.6*2 = 1.2V, maybe a bit less depending on the Diodes you use. This would then power your system with 4.8V on a new set of batteries and will simply drop from there as the batteries are discharged.

     

    Of course a better option is a low drop-out regulator to run at 5V but of course your going to have it fail before the batteries are discharged.

     

    Even better would be a Buck regulator powering your system at 3V3 instead of 5V. these are much more efficient than a low drop-out regulator or the diodes as your not throwing power away across the regulator/Diodes so your batteries will last much longer

     

    The only down side of running the system at 3V3 is that the micro-controller will need to run at 8Mhz instead of 16. But considering your project I don't see this as a problem

     

    Hope this helps regarding the power situation

  • 0 in reply to Robert Peter Oakes

    Peter

    Both suggestions are reasonable given the design.

     

    I think the 3v3 regulator is the best option, since it will give the longest run time.

     

    The third option is to use rechargeable batteries, as their voltage is 1.2v  (4 x 1.2 = 4.8v)

     

    Your design appears to not have a xtal/oscillator, so it runs at 8MHz anyway (page 33 of the ATmega 328 manual)

    You might need to load it using a different board, but there is some info here (change to 328)

    http://wolfpaulus.com/jounal/embedded/minimalarduino/

     

    Mark

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