Vehicle Speedometer Frequently Asked Questions

The spatial filter detector measures speed by optically capturing the "uneven pattern of the road surface," so if there are puddles on the road surface or the optical system is covered in muddy water, measurement becomes impossible. For this reason, we have determined that use on rainy days or when there is standing water on the road surface is generally not feasible, and although we have implemented simple "splash-proof measures," we have not taken any special waterproof measures.

If water is expected to enter the spatial filter detector through gaps, for example, if it is splashed with water or if the detector is positioned in the path of rainwater falling on a vehicle, please keep the detector covered with a waterproof sheet such as plastic sheeting at all times. In this case, the cover of the floodlight will generate considerable heat, so please take care to ensure that the waterproof sheeting does not come into direct contact with it.
Also, please note that if a waterproof sheet such as vinyl protrudes into the optical path of the light-receiving unit, it will affect the received light signal and may cause measurement errors.

The purpose of the floodlight is solely to illuminate the road surface and make "uneven patterns on the road surface" more visible, so even if rainwater accumulates in the floodlight, it will have little effect. However, if measurements are taken over a long period of time, vaporized water vapor may reduce the amount of light emitted or negatively affect the halogen lamp. Also, if dirty water spray from the road surface enters the floodlight, the amount of light emitted will decrease, and the signal-to-noise ratio of the detection signal will deteriorate. If water accumulates inside, immediately remove the floodlight hood, empty the water from inside, and clean the protective glass.

On the other hand, if a similar phenomenon occurs in the optical system on the detection side (inside the objective lens), it will affect the image formation, significantly reducing detection capability and making measurement impossible. In this case, allow it to dry slowly in a dry room. If it is severely wet, it may be necessary to remove the objective lens and clean it, in which case we recommend calibration the detector.