“Many IOT projects operate intermittently. If they have to run by battery this is an enormous power drain. For example, a project that operates 30 seconds every 10 minutes wastes 95% of the battery capacity!
This circuit manages battery power so only 250 nA are used in the idle time (that’s 0.00000025 amps!)
Most micro controllers have a low power standby mode but they still need power to keep the processor alive, also any peripherals will consume power. It takes a lot of effort to get standby current below 20-30mA. This project was developed to report temperature and humidity in bee hives. Because of the remote location battery power and a cell shield for reporting data where the only choice.
This circuit will work with any controller and 12, 5 or 3V power.
- Resistors: 2x1K, 3x10K, 1x470K, 2x1M, 5x10M
- Diodes: 2x1N4148, 1xLED
- MOSFET: 3x2N7000
- Clock: PCF8563 or equivqlent for microcontroller
- Relay: EC2-12TNU for 12V supply
- EC2-5TNU for 5V
- EC2-3TNU for 3V
- Power: OKI-78SR-5/1.5-W36-C 12V to 5V Converter or as required by microcontroller
- Switch: Momentary press for reset, SPDT for test”