Magpie
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Harbor Freight digital scale - need help
I just bought the digital scale shown in the following link:
http://www.harborfreight.com/digital-scale-95364.html
I bought it to monitor the weight gain of a gas/liquid reaction as it progresses. With a capacity of 5 kg and a resolution of 1g it should workout
well for this purpose. However, the scale automatically shuts off after 40 seconds of operation. I need to somehow override this function. Does
anyone have any idea how I can do this? All suggestions are appreciated.
[Edited on 16-8-2014 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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WGTR
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It may be built into the programming of the controller.
My kitchen scale stays on as long as the weight changes periodically. Otherwise it shuts off too. Sometimes they are smart enough to not zero-out
if they turn off with something on the scale, but not always.
I suppose that the manufacturer thinks they are doing you a favor by prolonging battery life.
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Magpie
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Yes, this scale seems to time-out with or without a load, changing or not. If the timer is built into the software then I suppose I'm screwed. There
are what looks to be two capacitors (or transistors) wired to the circuit board. But I don't know if they are related to the timer or not. My
knowledge of electronics is very limited.
The single most important condition for a successful synthesis is good mixing - Nicodem
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ScienceSquirrel
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I have a digital scale that I use for brewing.
It turns off after a few minutes on batteries but when on mains adapter power it chugs on.
Smart scale!
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Magpie
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I wasn't so sure about it turning off when under a changing load so tested it again just using finger pressure. It stayed on! So it looks like I'll
be OK after all.
The single most important condition for a successful synthesis is good mixing - Nicodem
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careysub
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Quote: Originally posted by Magpie  | I just bought the digital scale shown in the following link:
http://www.harborfreight.com/digital-scale-95364.html
I bought it to monitor the weight gain of a gas/liquid reaction as it progresses. With a capacity of 5 kg and a resolution of 1g it should workout
well for this purpose. However, the scale automatically shuts off after 40 seconds of operation. I need to somehow override this function. Does
anyone have any idea how I can do this? All suggestions are appreciated.
[Edited on 16-8-2014 by Magpie] |
The HF scales are inexpensive, and readily available most places - but they are problematic for lab work. They are better than nothing, and can serve
as a back-up but there are a number of limitations.
One issue I find is that they do not like you to keep adding stuff incrementally, at some point they decide you must be done and quit registering more
mass - or else become "sticky". I have found the need to be alert for an addition not registering when you expect it should, thus indicating you've
reached the end and need to reweigh. (And don't short cut and add directly to mixture on the scale, unmixing proves difficult).
They are what they are.
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Magpie
lab constructor
Posts: 5939
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I have an Ohaus triple beam mechanical scale that I use for everyday weighing for my experiments. I expect it will outlast me while giving no
problems. This HF scale will only be used for special purposes such as the one I described above.
I have bought a number of HF tools. They are OK for occasional use while being much cheaper than quality tools.
I would still like to disable that pesky shut-off timer. So if anybody knows how to do that please tell.
[Edited on 17-8-2014 by Magpie]
[Edited on 17-8-2014 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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kt5000
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I have a similar scale purchased online. Cheap and fairly accurate, but it also times out. If I press the "On" button periodically, it won't time
out. I suppose I could rig a circuit trigger that constantly. Maybe even shorting that switch would do it.
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