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
    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

    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.

  2. ericgibbs

    Senior Member

    Jan 29, 2010
    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.
    • 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.