The Raspberry Pi has been a revolutionary computer in the maker space, providing a full Linux environment, GUI, and tons of GPIO and other interfacing protocols at a considerably low price. This wasn’t its original intended goal, though. Back in the early 2010s it was supposed to be an educational tool for students first, not necessarily a go-to for every electronics project imaginable. As such there are a few issues with the platform when being used this way, and [Vin] addresses his problems with its power management in his latest project.

[Vin]’s main issue is that, unlike a microcontroller, the Raspberry Pi doesn’t have a deep sleep function. That means that even when the operating system is shut down the computer is still drawing an appreciable amount of current, which will quickly drain some batteries. We’ve covered [Vin]’s farm and his use case for the Raspberry Pi in the past, but a quick summary is that these boards are being used in a very rugged environment where utility power isn’t as reliable as he would like.

In [Vin]’s post he not only outlines his design for the board but goes through his design process, starting by using discrete logic components and then trying out various microcontrollers until settling on an ATmega88. The microcontroller communicates with the Raspberry Pi over I2C where the Pi can request a power-down as well as a time for future power-on. A latching relay controlled by the microcontroller ensures the Pi doesn’t drain any battery while the ATmega can put itself into actual sleep in the meantime.

The build for this project goes into an impressive amount of detail, and not only are the designs and code available on the project’s GitHub page but [Vin] also wrote another blog post which uses this project to go over his design philosophy more broadly.