Suggestion for mini weight sensor

Discussion in 'General Electronics Chat' started by Anuraag Mohan, Jun 7, 2015.

  1. Anuraag Mohan

    Thread Starter New Member

    Jun 7, 2015
    1
    0
    Hi,
    I need to measure weights ~ 1KG for a project and am looking to see what the most compact way of doing so is. I looked at FSRs but they are not repeatable or accurate. I couldn't find a good way of using a MEMS pressure sensor for measuring weight.

    The next best option is to use a load cell like this one

    http://www.ebay.com/itm/like/221642694047?lpid=82&chn=ps

    I have seen them in kitchen scales, and assume them to be accurate. I tried to hook one of these up to an INA125 and Arduino board, but needed to press it really hard to get a reading. Do I need to stick this load cell to a substrate to generate strain.

    Thanks
     
  2. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,504
    380
    hi,
    The load cell you linked to has the attached specification.
    If you use 10Vdc excitation it will output 1mV/Vex = 10mV at 1Kg full scale.
    It is customary to use a Instrumentation amplifier [IA] to amplify the low level signal to a more useful voltage.
    A typical IA gain would be set for 5Vout/10mV = 500, the 5Vout would then be converted using an ADC converter, if you planned to display the weight digitally.
    E
    Description:
    • Model:Weighing Sensor
      Rated Load: 1Kg
      Rated Output: 1.0mV/V±0.15mV/V
      Zero Output: ±0.1mV/V
      Creep: 0.03%F.S./30min
      Input End: Red+ (power), Black-(power)
      Output End: Green+(signal), White-(signal)
      Recommended operating voltage: 3 ~ 12 VDC
      Maximum operating voltage: 15 VDC
      Input Impedance: 1115±10%Ω
      Output Impedance: 1000±10%Ω
      Protection class: IP65
      Total Size: approx. 3.15 x0.50 x 0.50 inch
      Cable: 0.8 x 20 cm (diameter x length)
      Material: Aluminum Alloy
    This load cell is designed for mounting between a Base plate and the weigh platform.
     
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