USB datalink instability caused by other loads on circuit?

Hey Everyone, I’ve heard some general comments about USB serial data connections being finicky and dropping out, but I have not seen any suggestions on how to address the issue.

I’ve had two jobs fail on my Eleksmaker 2.5w diode laser recently because the laser lost connection in the middle of the job and reset. I assume this is due to some kind of electrical interference. One time happened when the motor on my Harbor Freight airbrush compressor (my air assist) cycled on and off… and the second when I plugged a cell phone power charger into the powerstrip that was on the same outlet as the PC, but not the same powerstrip as the PC (using a UPS for the PC to guard against power outages).

Can anyone direct me to some knowledge on this topic? I’m apparently not googling this with the right search terms. I need this laser to keep working whether or not I have to plug or unplug something else in the shop!


Take a look at ground loops.. It has a good explanation, but is geared toward measurement equipment. The phenomenon is the same though. In short, if all the equipment doesn’t have the exact same ground, you should add a ground cable between them. “Same” would be the same outlet on the same breaker. One on outlet, one on power strip on the same outlet, and one on UPS on the power strip on the same outlet, aren’t necessarily the same ground (although they should be).

Also, motors are VERY electrically noisy devices. Combined with the above, you need to be really careful with how things are connected.

Also, in general, anything with an AC motor shouldn’t be run through a UPS.
A surge protector is not necessarily a noise reducer. You should at least have a surge protector (not a “power strip”) and preferably one that specifically says it has a noise filter as well.

For plugging in the phone, it could be coincidental or a REALLY bad/noisy switching power supply in the charger.