Force Probe

The TEEMSS Force Probe has two force ranges: +/- 20 and 200 Newtons. The smaller eye bolt measures forces in the range of -20 to +20 Newtons. Forces from -200 to +200 Newtons can be measured at the larger eyebolt.

Force Probe assembly with 4' flexible cable and probe card

Force Probe assembly with hall effect sensor circuit board and cylindrical magnet.

Operation:

Positive or negative forces are applied to the free end of an aluminum beam which produce displacements proportional to applied force. The displacement of a cylindrical magnet attached to the end of the beam is measured with a linear hall effect magnetic field sensor. The long axis of the cylindrical magnet is oriented in parallel with the plane of the hall effect sensor and in line with the arc of displacement of the end of the beam. The distance of the magnet from the active plane of the hall effect sensor should be 1/2 the length of the magnet for most linear response. With this topology a linear relationship exists between displacement of the magnet and the voltage response of the hall effect sensor as long as the displacement is limited to prevent either end of the magnet from extending past the active area on the hall effect sensor.

Force Probe mechanical assembly drawing.

Allegro 3516 Ratiometric Linear Hall-Effect Sensor

Neodymium sensing magnet from WonderMagnet, Item #26 1/8" diameter x 3/8" long rod $0.25

Original Force Probe prototype