backup supply for pic

hello

i use adapter for supply my pic.but if i off the adapter the supply willbe off and i lost the data. so i want build the backup power supply my pic.
can some one help me

It seems like all you would need would be a battery of some sort going to your PIC through a diode. As long as you have a large enough capacitor on the power pins of your PIC, this would keep your memeory if the main power supply was lost. Of course, you might also want to add some sort of alarm so you can respond and fix the problem before the battery runs down.

Hi,

You also could dectect the mains voltage drop on an "interrupt" pin and, with a suitable supercap to allow some time to put your values into the EEPROM ...save them before power definitly off.

depends on what you intend to do ... and we don't know anything about your project !!!!

Alain

thank..

i cant put alarm for my system. i build automatic meter reading. if i put the alarm the customer know my system. this for my final year project

so what my idea i want build backup supply using rechargeable batteries. if supply off the batteries can supply the pic and if the adapter supply come back the batteries will be charge.

so can u help me.
i try find the schematic for rechargeable batteries, but cant find...

or pic can save data to the memory(Eeprom) directly.

Does that mean we get the credit for "your" final year project? Just out of interest, what course have you been studying and for how long?

thank for alll.

i success build buckup supply.

i put this forum in my tesis...