Interface Load Cell With ARM7


Load cell is a passive transducer or sensor which converts applied force into electrical signals. They are also referred to as Load transducers. There are many varieties of load cells, strain gauge based load cells are the most commonly used type.

  • Load cells use different operating principles.
    Load Cells based on fluid pressure.
    Load Cells based on elasticity.
    Load Cells based on magnetostriction effect or piezoelectric effect.
  • Load cell primarily consists of a spring material and strain gauge.
  • Spring material causes strain due to applied load and strain gauge changes its resistance in accordance with the change in strain.
  • A mechanical arrangement, the force being sensed deforms a strain gauge.
  • The strain gauge measures the strain as an electrical signal.
  • A Load cell usually consists of four strain gauges in a Wheatstone bridge configuration.
  • Load cells of one strain gauge (quarter bridge) or two strain gauges (half bridge) are also available.
  • The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used.
    The output of the transducer can be scaled to calculate the force applied to the transducer.


  • Weight Machine.

Hardware Required

  • Load Cell.
  • Instrumentation Amplifier.
  • LPC21XX MicroController.