Robert Linton

A triple IR sensor!

38D

Great work as always. Where do you use to lable your wires? They are so nice and neat.

wsybert

I love what you are doing.... i do similar stuff at work (Automation and SCADA). I would love to put sensors on my car... not sure what I would do with the data though .
Nice work!

Geoffrey

Hi Bob, that piece looks nice. I see that it is a 7.4v to 30v device, that is interesting since most of the sensors I have been using are 5v supply. Good thing the MoTeC has both 5v and 8v floating ground circuitry. What do you do if one IR sensor is damaged?

Colin, the labels are a standard Raychem part and you can print them on a dot matrix printer or an expensive printer specific for labels.

Geoffrey

While I am working on the additional sensors I also purchased some small flat bearings to install under the spring. Since a spring rotates when it is compressed, the thin bearings will allow ths spring to move more freely. You can see the bearing under the main spring.

I started looking at how to mount the linear position sensor and decided that in the front I'll install it on the top of the lower control arm and mount it to the frame rail. I measured the distance and it moves 1.5" so I buy a 50mm linear potentiometer and make a few brackets. Since it won't be mounted on the damper itself, I'll need to write a custom calibration that takes into consideration the motion ratio of where the sensor is mounted vs the actual damper position. In the rear, I am going to mount the sensor directly on the damper.

NineMeister

Since the A-frame moves in an arc and the damper is linear, although the angle change is small there will definitely be a small mathematical variation if you assume that it is a linear correlation. I take it that you are simply going to remove the springs and calibrate the sensor against the actual damper travel measured with a DTI rather than estimate the function?

Nice work though Geoffrey, your dedication to the cause astounds me. I just would not have the inclination or patience to do all this on my own car - it takes me too much brain effort driving the thing and remembering where I go wrong let alone working out what the car is doing wrong as well. Hopefully it will be your customers who benefit in the long run.

Geoffrey

Man, I look at these pictures on the web and realize just how dirty the car got in only a short time. It's not long ago when everything is sparkling white. Oh well.

Colin, yep, you are exactly right. because of the arc of the lower control arm, I cannot simply provide a motion ratio to the calibration ie 25mm of suspension travel = 5mm linear pot travel x MR of 5. I will need to do exactly as you say which is to remove the spring and move the wheel a predetermined amount, say 5mm and take a reading of the voltage of the linear potentiometer, and repeat the process through the approximate 4.5" of travel. What is a DTI?

The sensors should go a long way in helping to set up the chassis since it will give detailed information about what is happening while the car is in transient.

Laurence Gibbs

Dial Test Indicator? DTI ? maybe? or how about damper test instrument. ?????? just guessing

Geoffrey

The linear potentiometers for the front suspension arrived last week and I picked up some parts that had to be machined to mount the sensors to the front suspension. Now that I completed the 996 GT3R twin turbo project I had some time install the sensors on the car. I will create a custom calibration that will represent the actual damper travel, one for each front sensor. The rears have yet to arrive and will be mounted directly on the damper itself.

I'm planning to go back to the dyno in 2 weeks after the Sebring club race and will retune the car for open exhaust. I will also have the car at Farnbarcher Loles for the Zone 1 Tech Tactics event where I'll be presenting. Only 55 more days until I am back on the track!