[time-nuts] measuring currents on USB powered devices

[Hal Murray]

jimlux at earthlink.net said:
> What would be great is if there were some USB "thru" pod that measured  this
> and reported the data over a USB interface (recognizing all sorts  of
> isolation issues that are possible), so I could plug the USB power  "to" the
> beagle board and the USB power to the RTL-SDR, and log them both. 

I don't know of anything like that.  Please let us know if you find something.

One item to add to your list.  I don't know about Beagles, but Pis are 
sensitive to not-enough voltage on the power input.  I've seen various stories 
about flaky operations going away when power was cleaned up.  The typical 
wall-wart for a Pi is spec-ed at 5.25V rather than 5 and you can get USB 
cables with fatter power wires.  The sense resistor to measure current adds to 
the problems.

I have one of the little USB in-line meters.  You could point a camera at one 
of them and OCR it.  That would solve your isolation issues. :)

-- 
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