Measure sensor angle
This tool turns a top-down photo into the cosine error angle used in Site Settings. Place two points along the straight part of the kerb nearest the car, then two more along the sensor baseplate, and it works out the angle for you. That matters because the speed correction depends on this number, and the computer will cheerfully do the wrong maths if you give it the wrong angle.
What you are measuring
- Take the photo straight down, perpendicular to the kerb, so the geometry is trustworthy.
- Tap two points along the straight part of the kerb near the car. The grey line sets the road direction of travel.
- Tap two points along the sensor baseplate. The emerald line is the sensor line the tool compares against the kerb reference.
- Tip: when mounting aim for an angle of less than 30°. Lower angles need less correction, but the beam still has to cover the full lane.