Velleman SPBS4 Notice D'emploi page 5

• Reversing signal: indicates the vehicle is reversing.
• Direction indication: the sensor that detects the obstacle lights on the screen so the driver will know the precise
location of the obstacle.
• Area indication: it tells you whether the obstacle is found in the safety, caution or danger zone.
• Distance indication: distance is displayed as soon as obstacles appear within 2.5m behind the vehicle. "-P" is
displayed when an obstacle is closer to the bumper than the min. detecting distance
• Beeping distance: the system starts beeping when an obstacle is detected within 1.7m of the central sensors or
within 1m of the side sensors. The warning volume of the built-in buzzer is adjustable.
b) Important remarks (fig. 3, 4, 5, 6, 7 and 8)
• The reversing speed must be kept under 5km/h for the system to work.
• The system incorporates highly sensitive ultrasonic sensors and uses fuzzy logic. The blind area is minimal and
the SPBS4 has a long detecting range. The detection result measures the distance from a sensor to the surface
of the obstacle that reflects the waves. However, the user must remember that the measured distance is
influenced by the positions of the installed sensors, the shapes and locations of obstacles, the reflecting angle
and other factors. Therefore it is advisable to visually inspect the situation behind the vehicle before reversing.
• Detection is not guaranteed in certain cases. A few examples:
1. In figure 3 (see below), surface a is closer to sensors than surface b, but surface b is more reflective than surface
a. As a result, surface b is detected first, whereas surface a may not be detected. If obstacle c has a smooth,
glassy surface and angle A is very wide, this obstacle may not be detected at all.
2. Point A in figure 4 (see below) may not be detected.
3. Consider figure 5 (see below). Although obstacle Ta-b is closer to the ground than the sensors, surface Ta-b will
be detected first because this surface produces the strongest reflection. As obstacle Tc comes closer, however,
its reflection becomes stronger than that of Ta-b. Consequently, the system will forget about Ta-b and will instead
start warning you for obstacle Tc.
4. Certain obstacles have a strong absorbance of sound waves e.g. clothing. For instance, a person may not be
detected until he/she is approximately 1m behind the vehicle because the person's clothes absorb the ultrasonic
waves (see figure 6 below).
5. Certain obstacles are located outside the system's detection range (see figure 7 below). Obstacle B will be
detected while obstacle A may not.
6. The system may emit beeps if the road surface is very irregular.
7. There is a blind area of 22cm immediately behind the vehicle. Obstacles in the blind area can never be detected,
but it's normal for the system to produce false detection results from time to time (see fig. 8 below).
SPBS4
5 VELLEMAN