Weight Packing Machine / Load Cell

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>>1197493
>'potato chips..'

Maybe use one of those tiny scales that teenagers use to weigh their drugs.

>>1197500
I'm white.

It's actually Yuca(cassava, mandioca, macaxeira) chips. I'm a Jr in electrical engineering. Got to pay rent... So i have to work.

>>1197502
I use one of those now, but it's a slow process and takes loads of time. I want to creat a machine to automatize the process.

>>1197512
Okay well since that flew over your head let me break down what the other anon is saying. Maybe use one of those tiny scales that teenagers use to weight their drugs. As in take it apart, get a basic understanding of how it works and how you can interface with it.

Hi there, have you taken a look at small-scale strain gauges and FSR's? I think for vefry small loads you should try an FSR.

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Ok, use spring, have the think hooked up to a needle with gradeations, speend like three weeks getting opencl to read your needle then give up, go on ebay and covet this thing.
http://www.ebay.com/itm/10-head-electrical-weigher-computer-smart-scales-for-granulated-products-/192087801373?hash=item2cb9533e1d:g:uv8AAOSwImRYdon6

Get motivation back anfter watching shila bluff tell not to let dreams be meames tear apart food scale, try to put its shit on raspburry pi, find out that raspberry pi has shit for a to d, try arduino, same proble, get ESP-32S because it actually has a to d, cant get it to load in arduino ide because half retarded, buy a to d module for pi, now can code in python like a boss calibration is all shit and non linear, have to make curves and shit with a calibration talbe, finally finish scale, add servo to dump shit into bag, hook it up and all calibrations are shit again because added hardware, re do calibrations, use it for a while, find the calibration goes out of shit, turns out springy spring is getting worn out because too retarded to figure out correct spring, come back to /diy/ and ask if anyone knows shit about springs, what the fuck amd I wasting my life on, I could have just bagged like a simi truck full of this shit by hand had I not been trying to automate it, get frustrated, blow up orphanarium shouting 'allah who snackbar'.

>>1198046
Nice rant. Now go learn about load cells. Here is a tip. Call a company that makes load cells. Ask who there distributor is in your area. Arrange for them to send some engineering samples and request pricing and data sheets to make it sound official. If they have problems with sending you samples tell them you will pay the shipping (solves most problems). Now with your almost free load cells with calibration curves from the data sheets you can properly program your micro to read the data.

Or

You can buy a load cell from here for $7
http://www.robotshop.com/en/100g-micro-load-cell.html

Le shit...

Obviously a junior engineer.


Most governments has a weight and measurements division for weigh scales used for tender. Before you cheap the fuck out go find out what the legalities are in your area about selling preweighed anything for tender.

I know Canada has its own. They seal the calibration for it. Regular inspections. Then you can use it to sell shit.

Load cells typically take an excitation voltage from a controller and the resulting signals get averaged. Hence its more than 1 cell would be required for your setup and they both have to be the same. Usually this comes with a controller from the manufacturer.

As for your sealer you could salvage an old vacuum sealer and use the heat strip. You want to ensure there's air in the bag to protect your product. Typical the bag gets inflated so the customers don't have dust to eat instead of chips.

Be better off buying a used one on ebay and retrofitting it. But without ensuring legalities ur just asking for issues.

>>1197493
Load cells are a low voltage wheatstone bridge circuit. You use a standard test weight to get a voltage value for that weight. You then get a linear relationship between voltage and weight along the load rating of the load cell.

http://www.utilcell.com/en/content/load-cell-electrical-circuit

https://airtripper.com/1626/arduino-load-cell-circuit-sketch-for-calibration-test/

Yo I actually but one of these a few years ago to bag flour. Three load cells to ADCs to an Arduino worked alright but this was for 5 lb bags. Iunno if they make accurate load cells for that little weight. Anyway read the data sheets for all your parts and make sure your ADCs are quick enough for your desired accuracy. Also recommend brushless motor for ez pz braking.

>>1197493
>but i have not found a load cell that works with small loads
you haven't looked very hard.

Heres how I would do it.

A conveyor belt drops the chips into a box which is on top of four small load cells, creating a wheatstone bridge. The output of the brige goes into an operational amplifier, and then to an arduino. When the ADC of the arduino detects the voltage corresponding to the desired weight a door in the box opens and the chips are dropped into a bag, then the door closes and the process repeats. The amplifier should have a low pass filter to eliminate spikes from the chips falling at once and the arduino should average readings.

If you're looking to do portion control, fucking forget about weighing shit and do it by volume. I can tell already that your shitty load cell contraption is going to have a tolerance of +/- 100% anyway.

>>1201797
That could be replicated mechanically much more easily using a counterweight seesaw.

>>1201797
>four small load cells, creating a wheatstone bridge.
i might be able to reply to this post if i hadn't died of disappointment.