How to Profile Battery Usage for IoT Devices - Workbench Wednesdays 56

Can you share pictures of your connections?

I sure did…

I also tried following the instructions and doing Source mode… same noise.  This is what had me thinking I may just have a faulty device.

Did you put the PPK into Ampere meter mode?

Under mode, that is a toggle for "Source Meter" and "Ampere meter." It defaults to source meter (where the PPK provides power.)

Also, you might try turning the device on and off while connected. It'll cause the nRF Connect software to reflash it (if necessary).

oh, and of course I tried different wires!

I didn't completely clarify, on the LED test if I wired VOUT and GND, then the LED came on... but still not anything but noise on the software for the PPK2.

I've bought the PPK2 and either I'm a moron, or the device is faulty.  How do you suggest I figure out which it is (right now odds are even, in my view)?

I tried it out with my DWM3001CDK, which has current measurement pins.  I've verified continuity there and that removing the jumper disables the MCU.  I've linked up my PPK2 wiring up VIN/VOUT on the current pins, and the two grounds onto the board GND.  Nothing but noise in the nano-amperes... it's worth noting the values don't change even if I disconnect the power from the DWM3001CDK... a pretty strong indicator that it's not actually doing anything.  I've also tried it with the PINs reversed, just in case I've done something terribly silly (which I'm sure I hadn't).

Given that it didn't work, I tried a much more complex circuit.

1. Bench power supply tied to + and - rails of a breadboard.
2. Resistor and LED in series.

Everything lights up fine...then I put the PPK in series and the LED won't come on, and it's just noise on the nRF connect Power Profiler.

Anyone want to suggest a further test I might do?  Or even walk me through how you'd wire it up if yours works fine?

I have a Joulescope. I backed the original Kickstarter. But I haven't used it enough!

Nice little device from Nordic.

ST also has a kit for power consumption measurement, especially (but no limited to) Nucleo boards. https://www.st.com/en/evaluation-tools/x-nucleo-lpm01a.html

Another solution is a Joulescope. It doesn't have an integrated power supply, but performs great for the price. We also use it at work for longer data logging. https://www.joulescope.com/

I used Joulescope for a power profiling of my IR thermometer: /challenges-projects/project14/energy-harvesting/b/blog/posts/measuring-nanoamps and I was suprised how well it performed against a Keysight precision DC supply that was about $14 000: /challenges-projects/project14/energy-harvesting/b/blog/posts/measuring-nanoamps#jive_content_id_Keysight_N6705CN6705C_power_supply_with_N6781AN6781A_unit