I'm trying to instrument a vehicle component. I want to measure a component's angle during a drive cycle. The component has a single degree of freedom, it has a fixed axis. I'm trying to figure out an efficient way to measure this. I'm hoping to use Internet of Things (Raspberry Pi / Arduino) technology as appropriate. Without going into details, I must power this thing via battery. I'm assuming the testing will be done during daytime, on asphalt or concrete pavement.
Sensors that seem to offer possibilities:
- Accelerometer (X,Y,Z)
- Electrolytic Tilt Sensor
- Passive InfraRed (PIR) sensor
- Radar sensor
- Sonic sensor
- Laser Time of Flight
My original thought was to use an accelerometer, attach it to the bottom of the device and analyse the direction of gravity to deduce component's angle. I know this would work on a fixed vehicle, but my situation is anything but fixed. I won't be able to deduce vehicle travel direction. Additionally, my vehicle's speed is not constant. I will be monitoring acceleration (but subtracting out gravity) while I'm looking for other characteristics...
Because of my huge variance in accelerations, I don't think a fluid based Electrolytic Tilt Sensor would work either.
My next thought is to accurately measure the distance from the component to ground. I'd fix the sensor to the movable end of my component, then calibrate distance observed to component angle, while vehicle is at a complete stop. I can monitor distance in real time to deduce component angle relative to the ground.
Scratch passive infrared. I'm pretty sure sunlight will mess that up bad.
Radar is a pretty nice technology, but seems to be oriented to metal, water or humans, and has a very slow response time. Scratch that.
And that leads me to either a sonic distance sensor or Laser Time of Flight sensing. At first glance both methods are cost effective and seem to work in the ranges I'm interested in. But I have no experience here. What I don't know is if on road testing in daylight will affect these devices. Will ambient noise mess things up? What about reflected sunlight?
Does anyone have any experience here with those last two technologies (Sonic Distance or Laser Time of Flight)?
Are there any technologies that offer an alternative method for measuring a component's angle (relative to the ground) in a dynamic, moving vehicle, perhaps something I've missed?
Note: I've done a lot of work using magnetometers and accelerometers (Ugh, remember the Vector Cross Product?) but I've never touched a gyro device. Are there opportunities there?