Remote Control Power Consumption

[jcsntoll]

Question:
I've seen alot of projects for IR remote controls.
they use many differnt PICs depending on the number of inputs needed.
( some use the PIC12F629  others might use the PIC16F628 )

But all of them seem to have power applied to the chip at all times.
I haven't done the math for the power consumption for the chips,
but wouldn't this limit the battery life of the device??

Would it not be better to use double pole switches, one tied to the power of the chip
and one tied to the input pin.. so when the users presses the button it powers up the chip
and also triggers the input.

Perhaps the power consumption of the chips is not really that much to worry about it.
It seems all consumer remotes work on the same way, having the controller chip powered at all times.

Any thoughts on this?
Are they any programming "tricks" to help conserver power?

Thanks for your input.

[pickit2]

Most remotes work on only use power when key is pressed, so they are in sleep mode most of the time.
this is in uA's so drain is less than shelf life of the battery in the unit, unless it's in the hands of my wife

[forter]

IR remote control unit wake up from sleep mode by interruption on change a state of microcontroller's input. After sending IR signal it goes sleeping again/
It is very important to program all fuses of MCU to reduce current consumption.

[aliveli]

you can use a pnp transistor which power up the mcu when button is pushed

[johnri]

The new generation of low power mcu use only a few microamps power
when in the sleep mode, the base current of a typical PNP transistor would
be higher than this.

I wouldn't bother with the external power-up circuit when using a low power mcu.

[oldvan]

Replace PNP "suicide" transistor with a MOSFET and no base current required.

Simpler to use low-power PIC.  Rechargable batteries or supercap can make power issues less a worry.