After a long time waiting, the USB type-C power meter is finally in stock again! Sorry for the long wait.

What is it?

A USB type-C power meter that will fit in-line with any USB-C connector and measure the voltage, current, power, charge and energy - as well as give an indication as to how stable and noisy your power supply is.

Why did you make it?

Because there is nothing on the market with good specs. No, let me rephrase that - there is nothing on the market with actual technical specifications. This product actually does have those, and I am really pleased with how precise its measurements are!

What is new in revision 1?

The meter is now self-calibrating - this means that it is now by design guaranteed to be in spec under all nominal operating conditions (4.1-24V input, -5 to +5A). For the previous revision, I had to hand-calibrate the meters, which is fine for point calibration, but does not account for long-term drift and is either prone to errors or relatively time-consuming.

When you use the meter with a product that can change voltage (e.g. quick-charging USB-C devices), the meter will perform re-calibration every time the voltage changes. This means the screen will freeze for about half a second. Don't worry, this is by design, and will only happen if the voltage changes rapidly and by a lot.

If you want a nice development board for the ATSAMD09D14A, you can additionally buy the SWD to ribbon converter ($5 add-on) so you can use your Segger J-Link or other SWD debugger to program and debug the microcontroller on this board. Binaries of the default firmware are available.