I have a kitchen weight scale containing four half-bridge load cells, each cell associated to one foot of the scale.
I want to hack it to use it as a pressure sensor and link it to an Arduino microcontroller.
With resistance measurement, I have deducted the sensors were linked using this configuration:
I have removed the original PCB and connected the sensors together the same way and also to an opamp (INA122) using the E+, E-, S+ and S- connections.
However I do not have consistent values according to the place where the pressure is applied.
I am now thinking about building four parallel bridges, each containing one load cell and three regular resistors. Each bridge would be connected to its own opamp. This would allow to better calibrate the output of each bridge and improve the balance between all of them.
- Is it a good way to combine the sensors and get a position-independant measurement ?
- Is there a better combination ?
Thank you in advance.