Hello

I have made an IR sender / receiver unit, and want to know the best way to power the sending unit.

Currently its using a PIC12F675 which is 5 volt logic, and this obviously needs to be powered by battery, id rather not have a 9V battery as there big and heavy, but two AAA's only make 3 volt.

is there any good way for getting from 3 to 5 volts? or any other things you could suggest to resolve this issue?

Many thanks
Dominic.

 

you could try a 3 volt to 5 volt DC-DC converter.
you can get a bunch of results on google for making these

or i used to skin my 9volts inside are six indiviual cells smaller then AAA, i dunno if that is recommended or not. you could remove 2 of the cells and get 6 volts.

 

From the 12F675 datasheet; "Wide operating voltage range - 2.0V to 5.5V"

 

Really, oh fantastic, sorry i really should of noticed that

thank you very much!

 

Brainfart, never mind

 

well all the circuitry is, is a pic 12F675, an IR LED and driving transistor

the IR LED is driven at 100ma at 62.5% duty cycle [30ma average] and thats it

when the PIC is not in use i plan on putting it to sleep which is 1nA @ 2V

operating current will be while it transmits the signal which is for around 18ms plus some calculation time call it 22ms with operational current 100uA @ 1mhz [im running it at 4mhz, 1mhz instruction cycle so roughly 400uA?].

so when sending IR data its around 400uA PIC + 30mA IR LED + 3mA transistor Base = 33.4 mA
and when in standby 2nA call it.

so not much

 

Argh, you read my post before my edit. For those saying huh? I had asked about IR power needs, then realized my post was a dumb question, then retracted my statment. Sorry for the confusion.

 

Personally speaking, I'm not good with maths. Though from what you have said, I'd just try the unit with a 3v supply and see how long it lasted etc.

That said, I have seen many examples of 'keyring' remotes that use a microcontroller ( of one kind or another ) and are powered by the good old 2032 3v cell.

 

lol dont worry, its not as stupid question as my original


Edit:

Thanks HoW, ill keep that in mind as then it will be even smaller, although my experience is that; that style of battery is very expensive [e.g. cheaper to buy a new watch than replace the battery]

 

I saw some 3V lithium battery cells at the Dollar Store. Only a few were leaking.
Guess where they are made.

__________________
Uncle $crooge