2022-08-08, 11:58
(2022-07-27, 15:50)jonfear Wrote: Edit 1. Look at the input voltage. Clearly this device requires more than the POE converter can provide. The supply voltage was circa 3.84v. Now plugged into a PI USB2 port and voltage is up to 4.2v and the device appears to be much happier...Another thing to be aware of is that many USB cables are absolute rubbish and will cause a considerable voltage drop, especially at higher currents. There's a guy somewhere who has posted a table of test results with different USB cables and some can't even carry 100mA without dropping outside the USB voltage spec, there was one that he described as "a long thin resistor" rather than a cable. So your problem in this case may not be the power supply but the cable leading from it.
However that was still not enough. Now powered by a wall wart supply and getting 4.72v+.