Quote Originally Posted by charudatt View Post
Its basically a code lock operating on 6V. A couple of flashing LED, Sounder (piezo) and a Solenoid.

Any help ?
Hi,

In order to ensure long battery life, your circuit must use almost no current in standby.
The PIC has a wide operating voltage range and has a sleep mode for power saving.
To drive the LEDs, piezo and solenoid, make the I/Os sink current. Drive the
solenoid with a PNP transistor. If you use four 1.5V cells in series, just connect the
PIC after the third cell (4.5V). The rest of the circuit (solenoid) will use four cells. (6V).
A diode in series on the battery minus terminal will be the simplest form of battery-reversal
protection.

Best regards,

Luciano