Muxtronics USB type-C power meter

The Muxtronics USB type-C power meter is a fully characterized, very high precision, bidirectional, transparent USB type-C measurement tool. It has 5-digit measurement resolution and better than 1% accuracy over the full measurement range and temperature, at 2.5 updates per second. The tool is open source hardware, but due to code shared with a commercial project the firmware is not open. The tool passes through, unhindered, any high-speed signals and has a measurement range compliant with all USB type-C devices, up to 20V and 5A. Both ways.

The meter not only measures voltage and current, but also calculates power, accumulated charge (during on-time) and accumulated energy (during on-time). These values are non-persistent and reset upon repowering the device.

Technical specifications

USB type-C power meter Rev. 0
AttributeValueUnit
Min.Typ.Max.
Width50.0
1.97		mm (incl. connector)
in
Length28.0
1.10		mm
in
Height7.40
0.291		mm
in
Weight8.3
0.292		g
oz
Voltage range4.124.0V
Current range-5.0+5.0A
Accuracy (V)±1% + 20% + counts
Accuracy (I)±1% + 60% + counts
Precision (V)±0.8mV (2σ)
Precision (I)±0.6mA (2σ)
Self-consumption18.024.2mA
Maximum displayable
on-time		99:23:59:59day:h:m:s
Maximum displayable
charge		500.00Ah
Maximum displayable
energy		5000.0Wh

Where to buy

The current (revision 1) version - with no casing - can be bought for $20 at my Tindie store. Optionally, you can purchase a programming converter for $5 to use it with your J-link pin compatible SWD programmer/debugger; this is a pretty nice development board for the Atmel/Microchip ATSAMD09D14A.

Documentation

USB type-C meter revision 1 schematic. Use the TinyCAD auto-purchasing tool to extract components and current pricing from this file.

Currently, the layout and firmware source are not open source

Revision 1 binary (ATSAMD09D14A). You need the programmer's edition (including the breakout cable) and a compatible SWD debugger (e.g. Segger J-Link) if you want to flash this.