weight switch

Thread Starter


Joined Jan 25, 2012
Hey Friends, I may have come to the wrong place as I have NO engineering background, but I found this site in my searching and figured I'd ask anyway.

I need a switch that turns a 115 volt machine on and off based on a specific weight. I make peanut butter in very small batches. I have a peanut butter mill. I put the cup under the mill and turn it on. When the container is full I turn the mill off, but I want to automate this process with a load cell or pressure switch device so that the container for the peanut butter sits on a scale and when the desired amount has filled the container the machine turns off automatically. Ideally I should be able to change the weight trigger in case I change container sizes. The weight is small. 12 to 16 ounces generally. I don't want to build this device myself. I'm looking for something off the shelf or possibly could pay someone to do it for me depending on cost.

Any ideas or suggestions are most appreciated. Thanks!!!


Joined Oct 15, 2009
How much are you willing to spend....

Many weigh scales have built in functionality for this. A simple call to a weigh scale company would be how I would start this process if I didn't want to do it myself.

You could also get creative and simply build a balanced mechanical platform that when weighed down would trigger a micro switch (heck even a regular light switch toggle)

Thread Starter


Joined Jan 25, 2012
Thanks for the replies. Man the captcha system for this site is difficult. took me a while to get logged back in....

I guess my budget is probably around 200 max. I don't want to buy a $1500 scale. I'll consider a balance beam contraption but i'd prefer a digital scale with a tare function.


Joined Apr 16, 2010
A simple tare function doesn't do all that you want, if I understand your needs. You want a scale that you can set to a certain weight, and when that weight is attained, the grinder is turned off. Right? None of the electronic kitchen scales that I have found do that. Maybe there is one, but I haven't found it.

So, I know that you said you don't want to build anything, but given your budget, some construction is probably going to be required. Although an entirely electronic option is possible, I think the simplest approach would be to attach a simple switching circuit to a balance scale like this one.