For many devices in remote locations without a power connection or sun, you want to achieve the longest possible lifespan and operating time without constant battery or battery replacement in order to minimize maintenance effort and costs. In a battery-powered context, a device should generally only be active for a limited time. There are two typical use cases:
- periodic reading of sensor readings (e.g. every ten minutes) and subsequent sending or logging (for autonomous sensor nodes) or
- short interactions, such as taking a measurement and displaying the result after activation by a user (e.g. in electronic geocache stations or luggage scales).
For the latter application, you could also use a device switch that physically separates the electronics from the battery. But that would be like in the last century. And people often forget to switch off the device, meaning that the battery quickly runs out. However, as we will see, power consumption can be minimized to a point where it is significantly lower than the self-discharge current of a battery. This is almost as good as disconnecting the electronics from the battery.
- Which microcontroller is economical
- Get to know the low-power library
- Optimization and adjustments
Which microcontroller family (MCU) you should use for such applications depends largely on what the MCU should be able to do. If you don’t need to do any computing-intensive tasks and you don’t need WiFi or Bluetooth, the energy-saving AVR MCUs that can be programmed with the Arduino IDE are ideal.
That was the excerpt from our heise Plus article “Power saving tips for AVR chips: Arduino in battery operation”. With a heise Plus subscription you can read the entire article.
