We've spoken about ways to reduce the power draw of Arduino-based projects in the past: last year we were fascinated by Nick Koumaris' temperature sensor running for an entire year from just three cheap rechargeable AA batteries, while Edward Mallon had some tips in October this year on minimising power drain in a data logger by removing unnecessary components. Other approaches have included zero standby current circuits and a switch to solar power, and now our friends at SparkFun have published a tutorial on reducing the power draw of any Arduino-based circuit.
Designed to be accessible to beginners, although some of the more advanced tips will require a steady hand with a soldering iron, SparkFun's guide covers how to monitor the power draw and techiniques on dropping the device's lower current level from 15mA to around 10uA - a massive saving in power equating to a major jump in battery life. Naturally, some of the tips look familiar: the guide begins with removing unnecessary components, just as Edward Mallon advised, as well as switching away from Arduino models which include a USB bridge and swapping out a linear regulator for a switching regulator.
Other tips are accessible to those who don't fancy heating up the soldering iron: SparkFun's guide includes advice on dropping the operating voltage from 5V to 3.3V, reducing the clock speed, and using various software tricks including disabling the analogue-to-digital converter (ADC) when it's not required and using a special low-power library to power on and off various parts of the microcontroller and send it to sleep when it's not actively processing things.
The full guide is available over on the SparkFun website.
When it comes to portable electronics, one of the most important features is how to maximize the battery life. The ATmega328P, used on popular boards like the SparkFun RedBoard, Arduino Uno, and Pro Mini are actually quite power hungry. The RedBoard and Arduino Uno, draw around 15mA minimum, which doesn’t sound like much but as you’ll see in this guide, we can drastically bring that down with just a few tricks. In this guide we’ll see if we can reduce the supply current to less than 10uA with a couple hardware and software tricks.