olkal / ATTINY-programmable-Power-switch

Programmable power switch for battery powered devices

ATTINY Power switch

This programmable MOSFET high side on/off power switch is based on the ATTINY85 chip and is intended for battery powered devices.

• 2-3 Lipo cells
• Max operating voltage 16.0V (18V never exceed)
• Max current: needs to be tested, but up to 5A should be safe. See MOSFET data sheet for info.
• Power consumption in "off" mode with BOD disabled: 3uA
• Power consumption in "off" mode with BOD enabled: 20uA

Configurable features in config.h file:

• LED behaviour
• Low battery voltage threshold, LED warning
• Very low battery voltage threshold, power off
• Button press and hold for a set time for power on
• Button press and hold for set time for power off
• Timer, delayed power off
• Timer, after power has been on for set time, switch power off
• PB3 pin signal (to for example a Raspberry Pi) initiating controlled shut-down, then switch the power off after a set time delay
• +lots of other possibilities...

Battery/voltage features using button switch:

• Auto calibrating internal voltmeter
• Auto set number of cells