This breakout board will solve all your multi-rail power-monitoring problems. Instead of struggling with up to 6 multimeters, you can just use the handy INA3221 chip on this breakout to both measure both the high side voltage and DC current draw of up to three power supplies over I2C with ±1% precision.
Most current-measuring devices such as our current panel meter are only good for low side measuring. That means that unless you want to get a battery involved, you have to stick the measurement resistor between the target ground and true ground. This can cause problems with circuits since electronics tend to not like it when the ground references change and move with varying current draw. This chip is much smarter – it can handle high or low side current measuring, up to +26VDC, even though it is powered with 3 or 5V. It will also report back that high side voltage, which is great for tracking battery life or solar panels.
A precision amplifier measures the voltage across the built-in 0.05 ohm, 1% sense resistors. Since the amplifier maximum input difference is ±163.8mV this means it can measure up to ±3.2 Amps. With the internal 13 bit ADC, the resolution at ±3.2A range is 0.4mA. Advanced hackers can remove the 0.05 ohm current sense resistor and replace it with their own to change the range (say a 0.01 ohm to measure up 16.4 Amps with a resolution of 2mA)
Usage is simple. Power the sensor itself with 3 to 5VDC and connect the two I2C pins up to your microcontroller – the logic level will be the same as the Vin power level. Then connect your target power supplies to VIN1/2/3+ and the loads to ground to VIN1/2/3-. If you want, set up over-current alerts on the warning or critical IRQ pins. We have libraries in both Arduino and CircuitPython/Python so you can use it with boards as simple as Arduino-compatible ATmegas all the way up to the latest Raspberry Pi’s.
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Python for Microcontrollers – Adafruit Daily — Python on Microcontrollers Newsletter: New Raspberry Pi Products, 503 CircuitPython Libraries and Much More! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi
EYE on NPI – Adafruit Daily — EYE on NPI Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey