Comment on Questions on how to connect a PC to a washing machine (USB→TTL serial)
diyrebel@lemmy.dbzer0.com 1 week agoI had the two 5v pins connected (from 5v on the adapter to the 5v pin on the washing machine). I had it that way for maybe 10 or 15 min until I was told not to. Now I wonder if I damaged it because when I meter the 0v against the 5v, there is almost nothing there. Did I damage it, or did the manufacturer disable the serial port before it got to me?
residentoflaniakea@discuss.tchncs.de 1 week ago
Hard to say, but if the 5V natively to the machine is shot, I’d expect the unit to not work as its systems would depend on it. I assume you measured 5V in reference to the machines GND. Double check your meter against a known good 5V supply (your adapter).
diyrebel@lemmy.dbzer0.com 1 week ago
When I meter gnd against 5v on the adapter, I get 5.15v. So both the adapter and the DMM are fine.
I heard that connecting two DC supplies together would have no problem if they both output exactly the same voltage. Of course we would never have an exact match, but the only strain on either side of the connection would be from the difference between the 5v from the adapter and 5v from the washing machine. So I’m tempted to conclude the serial port was sabotaged at the factory.