A little while ago I undertook the process of scratch building my own PC racing sim. It's all done now but one thing that i'd like to share with you all is how i accomplished a load sensitive brake pedal.
See, in a real car, the pedal does not really move all that much, even less in a race car. The braking force is then proportional to the force applied to the pedal and not the MOVEMENT. The problem lies in that most commercial pedal/wheel setups simply use a spring under the pedal and it detects movement of the pedal, but it just doesn't feel real.
Now, i don't claim to be the pioneer of this load cell idea but i would like to share the interface that i have made to enable one to be used. There is at least one commercial LC interface available by itself or built into a USB joystick board but it seems they have effectively stopped selling them. Hence, they are effectively unobtainable.
Step 1: How it works
What this interface does is multiply the output voltage of the cell to produce a 0-5v scale which then becomes useful to ether replace a 'pot' on a commercial pedal set or interface with the likes of an mjoy USB Joystick interface (That's a DIY Atmel AVR based USB joystick interface with 24 buttons and 6 axes).
The amplification is done with the help of a INA122PA from Texas instruments. It is pretty much purpose built for this task. All you need is a 0.22uf filtering cap and a resistor sets the gain.