Cheap but accurate USB Voltmeter / Ammeter?

[L5730]

Apologies that this is not strictly "audio electronics and hardware".

Does anyone have any suggestions for a cheap in-line USB meter to measure how much power is drawn by their DAC, headphone amp, audio interface or whatever USB device?

There are a bunch of very cheap USB testers but current accuracy in particular is unacceptable. I'm not talking high end multimeter accuracy, but we should be in the region of +/- 10mV and +/- 10 mA, do you not think? So 5.100 v could be 5.090 v or 5.110 v and 200 mA could be 190 mA or 210 mA. Much looser and it becomes rather useless.

I already have a multimeter, and whilst my own clumsiness could result in me plugging things in the wrong place, it's not highly likely.
I'm not really seeing any products out there that are just a USB pass through with the taps off for easy probing with a multimeter. Maybe I'm not looking in the right places.

I appreciate any suggestions and general discussion over this topic.
Thanks.

 

[L5730]

Looking at the specs for the Sinometer MAS-343 Multimeter (Maplins, remember them?) we have:

DC Current:

Range   Resolution    Accuracy
  4 V        1 mV      +/- 0.5% rng +/- 3 digits

  4 mA       1 uA      +/- 1.2% rng  +/- 3 digits
 40 mA      10 uA      +/- 1.2% rng  +/- 3 digits
400 mA     0.1 mA      +/- 1.2% rng  +/- 3 digits

5v at that accuracy level would be 0.025 or 25 mV, so my original desire is clearly asking far too much!
200mA at the above accuracy level would be around 2.4mA, which is needlessly accurate for our simple purpose.

So, for accuracy, voltage in the 0.5% range, and current in the 2% range would be fine.

I guess I should just make a little box with USB type-A male and female at either end, D+ and D- passed through, twisted and shielded. Ground taps and Voltage taps. Volt line completely severed, so requiring a jumper to allow any USB device connected to work.
I am surprised something like this doesn't exist and is less than a few £. Probably not enough call for it.

 

[JeffS7444]

David Jones demonstrates an inexpensive unit in action in a recent video:
https://www.eevblog.com/2020/07/14/eevblog-1319-new-ts80p-portable-usb-pd-soldering-iron-review/
His is a USB-C model, but the same vendor offers numerous other variants.

 

[L5730]

I've seen a few of these little inline USB measuring dongles. These ones with the data plotting over Bluetooth or to a PC seem rather neat, especially for around £15.
The problem with them is that I have no way to know if they are remotely accurate.

 

[L5730]

The model that David Jones shows in his video looks to be the (RD) Rui Deng TC66 (C) model. Only comes in USB-C flavour, although type C to A cables are cheap.
So much re-branding/counterfeiting going on with these little devices, I've no clue what's a decent one and what isn't.