Cheng Liang Makes His Three-Component Digispark Power Meter Portable — In a Mint Box

Maker Chen Liang is back with another microcontroller-driven power meter project — this time taking an earlier design and squeezing it into a transparent mint box for portability.

"This project reuse my previous project Digispark Power Monitor design," Liang explains of his latest guide. "It can continuous[ly] monitor the power usage of a dev device. It can help you develop a portable gadget with expected battery life. My previous power monitor built on a breadboard, it is not portable enough. So I want to squeeze it in a transparent mint box to save the space and more protection in normal use."

That previous project Liang mentions was released earlier this month, using just three off-the-shelf components to build a graphical power meter on a breadboard: a Digispark development board, based on Microchip's ATtiny85, a Texas Instruments INA219 current sensor, and an SSD1306-based OLED display panel. All together, the build read power usage of a device under test and displayed charts showing voltage, current, and power usage, while tracking accumulated power usage over time.

The new version uses the same components, and provides the same readouts — but the breadboard is gone, with the components squeezed into a box previously sold full of Jintan Nude sugar-free mints. The box needed a little modification, as did the breakout boards to minimize their size — but everything just about fits, with connectors for the device under test sticking out from the case's bottom. The only thing missing: you'll need an external power source.

The project is documented in full on Instructables.