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Need to find a load cell for Arduino

balearicdynamics

Hello.

I am searchng for a cheap sensor that can analog detect weight differences to do something like a scale. The weight range should be about 5 Kg max and about 0.250 min. I have searched for load cells but I have only found extremely expensive components so I have the suspect I am looking in the wrong direction. I am aware that in load cells the precision factor is almost constant so if the same cell can be used in a range of 1-10 Gr with a precision of 1/100 (I mean 0.01 g) the same cell measuring the range of 1-5 Kg the precision remain the same (or comparable). This is not a very influencing factor as it is most important to detect the weight vs time variation: I need to detect a weight variation in the order of less than 0.5 seconds and a continuous slow variation.

 

Any help will be appreciated. I know the principle but unfortunately in my past experience I have only worked with 10-1000 tons weight cells (always controlled by something like Arduino) and this is not the case.

 

Enrico

 

Update

Also a flexible sensor or force sensor can be useful to make this project. But also in this case I have not found reliable products, only (unreliable) flexysensors on baggood or from some small selles. I am searching flexible sensors (possible alternative) as well as load cells for cheap by a provider that can sell it as components. Not just kits, shields etc...

 

Message was updated by: Enrico Miglino

Parents

  • Hello,

    just two ideas: have you considered dismantling a kitchen scale / personal scale to find out, how is the weight measured?

    How about using some air bumper with an air pressure sensor?

    David

  • in reply to koudelad

    Hello David,

     

    both good ideas and unfortunately both discarded image with my regret. I already though to this but this should be a replicable project so I need to find a component. The second option I have not tried but I see that many other has done. It will work just for an experimental situation but not for a long term working case and probably the cost in time and cheap parts to it bigger than using a stupid analog sensor. It should exists if I can buy an electronic scale for 5 Euros ... I have the suspect that my difficult is to find the right search keyword.

     

    Enrico

  • in reply to balearicdynamics

    You can pay anything you like for load cells. A decent one, certified for retail selling applications in the UK will cost about £15 (15kg range) in decent numbers (10k per annum).

     

    But you can buy a cheapo from China here, starting at £2.73 with free delivery to UK.

     

    https://www.aliexpress.com/wholesale?catId=0&initiative_id=AS_20170526001504&SearchText=load+cell

     

    I did a lot of work (mostly a few years ago) with load cells and associated electronics, so come back and ask more if you like.

     

    MK

  • in reply to michaelkellett

    Thank you Mike, I will prepare a decent group of details then I will answer you better. You are very useful image

     

    Enrico

  • in reply to michaelkellett

    Michael, first of all I should say that part of my limits in finding the component is due to my correctness of the technical language. I have followed your suggestion and investigated searching for load cells; Farnell seems distributing only industrial expensive products (starting from 300 Euro / piece) as well as rs-online.

    Instead I have found on Mouser the availability of small analog sensors at a price of less than 10 Euro. As most of them are similar (just change some detail) the following can be considered the right one: http://www.mouser.es/Search/ProductDetail.aspx?qs=NTN7dFTirrsF%2feX8z2eK7w%3d%3d

     

    The project usage is nothing secret; I have in mind to implement the reading of the 3D printing roll weight to know when it finishes. The low range of these sensors for me will be perfect. Less than 30 grams means the roll is finished (the empty spooler weight is more than 30 g). Instead the higher limit opens a series of concerns:

     

    1. Using a 2Kg filament roll (total weight around 2,5 Kg) may create problems to the sensor until the filament does not reach a weight in the range? If not this can solve a lot of applicative problems.
    2. what do you think to a demultiplicator lever instead of placing the sensor just to the bottom of the filament roll base ?

     

    Thank you for your support.

    Enrico

Reply
  • in reply to michaelkellett

    Michael, first of all I should say that part of my limits in finding the component is due to my correctness of the technical language. I have followed your suggestion and investigated searching for load cells; Farnell seems distributing only industrial expensive products (starting from 300 Euro / piece) as well as rs-online.

    Instead I have found on Mouser the availability of small analog sensors at a price of less than 10 Euro. As most of them are similar (just change some detail) the following can be considered the right one: http://www.mouser.es/Search/ProductDetail.aspx?qs=NTN7dFTirrsF%2feX8z2eK7w%3d%3d

     

    The project usage is nothing secret; I have in mind to implement the reading of the 3D printing roll weight to know when it finishes. The low range of these sensors for me will be perfect. Less than 30 grams means the roll is finished (the empty spooler weight is more than 30 g). Instead the higher limit opens a series of concerns:

     

    1. Using a 2Kg filament roll (total weight around 2,5 Kg) may create problems to the sensor until the filament does not reach a weight in the range? If not this can solve a lot of applicative problems.
    2. what do you think to a demultiplicator lever instead of placing the sensor just to the bottom of the filament roll base ?

     

    Thank you for your support.

    Enrico

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