Suggestion for mini weight sensor

Thread Starter

Anuraag Mohan

Joined Jun 7, 2015
1
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
 

ericgibbs

Joined Jan 29, 2010
13,268
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
Do I need to stick this load cell to a substrate to generate strain.
This load cell is designed for mounting between a Base plate and the weigh platform.
 
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