Hi, I have a project of "NFC lock door system" using the PN532 (SPI com.) with the ATMEGA328P-PU, this system should used as stand alone system using some AA Alkaline battery for a year. after some search I found that i should do my own ATMEGA238 circuit to save power of remove the un-needed component in the UNO board, and to use Sleep functions in the code.
for the hardware it is Ok, I built my own ATMEGA328 board with less component with switch regulator instead of the 7805.
the question is, what is the best way to put my controller in sleep mode? and how to getting back to wake up when needed?!
and is there more change should happen in the hardware side for more power save?!
i Know it is very helpful link, but i need to know:
MMJZ:
what is the best way to put my controller in sleep mode? and how to getting back to wake up when needed?!
to be more specific, which sleep mode i should use? and how to wake up?!
knowing that i can't add button for the wake up (so not the INT0 or INT1 way), also the timer is not a good idea because it's mean it will wake up with no need of use, or the contrary it was sleep while user need it.
in a capital word: "I NEED IT TO WAKE UP ONLY WHEN NFC READ CARD"
MMJZ:
"I NEED IT TO WAKE UP ONLY WHEN NFC READ CARD"
This means that you have to have the NFC card reader powered continuously, so any power savings that you can make by putting the ATMEGA328 to sleep may only make a negligible difference to the overall current consumption.
Do you know how much current your NFC card reader uses?
I can't imagine that you will be able to power your circuit for a whole year on AA sized Alkaline batteries.
MMJZ:
i Know it is very helpful link, but i need to know:
to be more specific, which sleep mode i should use? and how to wake up?!
knowing that i can't add button for the wake up (so not the INT0 or INT1 way), also the timer is not a good idea because it's mean it will wake up with no need of use, or the contrary it was sleep while user need it.
in a capital word: "I NEED IT TO WAKE UP ONLY WHEN NFC READ CARD"
It needs an interrupt to wake it up. What drives the card reader to read the card to then wake up the Arduino?
Reading the data on the device gives a battery supply current of 140mA. Saving a few mA on the Arduino would seem to be wasted exercise.
Yeh, you alright Mr. "JohnLincoln". I surprised now when i see the PN532 take 150mA power consumption.
But I read in its datasheet that it may used in power save mode, i don't know how much the save power mode may reduce power consumption.
Do you have any advice for me Mr. "JohnLincoln", I can use any type of battery. my problem is with the connection, I can't assemble any power (or any) connection to the final system.