I find that 4 NiMH batteries (AA or AAA) deliver 4.8 volts for most of their run cycle, is there any problem using that instead of a "real" power circuit?
Problems I can think of are erratic operation as voltage dips, or the inability to use Li-Ion or Alkaline as the situation warrants.
Would there be a problem with using 4xAA NiMH for power?
Re: Would there be a problem with using 4xAA NiMH for power?
Oh, and of course the SD needs 3.3volts I guess.
Maybe the lack of a fail-safe in case of a short (IC burns instead of batteries)
Maybe the lack of a fail-safe in case of a short (IC burns instead of batteries)
Re: Would there be a problem with using 4xAA NiMH for power?
It would "probably" work. One thing to remember though is that we are overclocking the MCU, so higher supply rails help on the maximum frequency available. (I'd mentioned even running the MCU at ~5.25-5.5V in case we ran into any reliability problems at 5V).nubie wrote:Oh, and of course the SD needs 3.3volts I guess.
Maybe the lack of a fail-safe in case of a short (IC burns instead of batteries)
The UZEBOX stamp I did has a little 3.3V LDO on it to power the microSD card. (I didn't make that rail available on a pin though because it's only ~50mA and I didn't want it to be overloaded hanging other peripherals off it. A baseboard can have a beefier 3.3V supply if desired.)
A little boost converter running from two AA's kicking up to ~5V might be better?
-Clay