[moved] spooky scales at a distance.

Hi there. I wasn't really sure where to post this so forgive me please if its not where it should be. I was weighing out some ingredients in my kitchen earlier with 2 sets of scales. one which weights in grams and one which weighs to the point of a gram. i was trying to weigh out on the more accurate one and then the reading became very unstable and was jumping about all over the place. just as i started cursing myself for buying cheap i noticed the other set was doing a similar thing so i inferred that they must be getting interference from outside. i moved both scales to a different area and they stopped and then moved them back and they started again. i tried moving my mobile phone away and switching off all electronics and they still did it. eventually they stopped but i cant for the life of me work out what caused this. they were on a very stable flat surface, there were no discernible vibrations. as i said i switched off the only electronics in the immediate vicinity which was a desk lamp and this made no difference. i thought id post here just to see if anyone has any ideas at all. if not then i guess i'll have to put it down to ghosts but i dont really fancy doing that. cheers.

Re: spooky scales at a distance.

What if it was programmed to work like that sometimes intentionally like say if it is programmed not to take 20 readings and take its average sometimes. Is it chinese ? What if it a cheap product programmed to show a 20 kg as 25 kg sometimes ?

Re: spooky scales at a distance.

im not quite sure i understand what you are talking about.

@ gonadgranny
It's hard to guess what's going on without knowing what sort of scales they are. Presumably they're some sort of electronic scale, other wise you wouldn't be worried about electronic interference. If they are mains powered, the problem may be caused by low/eratic/dirty mains voltage at one location.

both battery powered digital scales.

Uh, could it be sub-sonic vibration ?? IIRC, an otherwise reputable electrical machinery engineer (EL) toying with gravity reduction via gyroscopes was *severely* embarrassed because the parcel scales he used had an asymmetric response to vibration...
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I'm not sure if relevant, but one bane of our 'analytical' lab balances was static electricity. You could close the shutters and get a stable reading, but trying to add a few milligrams to a tared scoop, fleck by fleck, could be an exercise in screaming exasperation.

We used aluminium or stainless steel mini-scoops, sometimes disposable anti-static plastic scoops. Glass funnel-scoops were neat, came by the dozen alike, were easy to rinse into a narrow-necked flask but, on days with really low humidity, you sometimes found stuff jumping *sideways* off spatula to the grounded balance pan.
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Another possibility is RFI, especially if the balances are not 'pro', UL or EU grade.

Long, long ago, a 'private hire' taxi with a 'boosted' CB rig crashed my Apple ][+ computer and trashed the lovingly compiled Assembler files on its floppy drive. His rig also broke through onto our TV, so we heard him rudely complaining he'd been sent to the wrong side of town...

More recently, a couple of NATO jets did a 'TOT' training run across our local airport. Their combined EM crashed a lot of our lab equipment, including much that was *supposed* to be shielded to 'medical' standard.

What really hurt is we'd just about re-booted everything, culled corrupted files, logged the mishap, generated fresh standards, prepared fresh eluents, re-run system calibration sequences etc etc when *another* pair of TOT jets came through.

F****k !!!

All the many product samples we'd prepared would be degraded by the time we got our systems up, running and calibrated again. We'd not only lost a complete day, impinging on sundry 'just in time' targets, we'd lost a lot of valuable consumables, generated a lot of toxic waste, had to run two lots of glass washing and were mortally p****d.

So, while us 'Lab Rats' went for lots of strong coffee and medicinal chocolate, our frantic managers phoned the airport, phoned Head Office, phoned Logistics, triaged the wrack, then phoned enough of the 'late shift' at home to warn them of a change in plans...