QKits Electronic Kits: K2599, Screen Wiper Robot kit

Intermittent Screen Wiper Control Kit Velleman Kit K2599

Features:

	Timer intervals: 5, 10 & 15 seconds
	Relay output: 2 x 5A single pole change over contacts
	LED indicator

This project is ideal for updating the windscreen wiper control installed in older cars. An intermittent setting, featuring three different time intervals of 5, 10 and 15 seconds is provided for matching to weather conditions. The advantages of intermittent wiping are that it extends the working life of the wiper blades and reduces the mechanical wear of the wiper motor and gearbox.

Specifications:

	Power supply: 12V to 15V DC
	Supply current
	output off: 25mA
	output on: 100mA
	Interval lengths: 5, 10, and 15 seconds
	PCB dimensions: 82 x 52 x 40mm

Installation in the car
On most cars, all electrical connections are numbered. A two speed motor has five connections. (fig. 1)
- 31 is the negative or ground connection
- 53 is connected to the + when wiping slowly
- 53b is connected to the + for high speed wiping
- 53a and 31a are the contacts of switch P which is controlled by the motor shaft. Switch P makes the screenwipers continue up to their parking position when the dashboard switch is turned off. Once they have arrived at their parking position, switch P goes from its 1 to its 0 position, short-circuiting the motor to make it stop before the wipers leave their parking position again.

Fig. 2 shows how the kit should be wired to the existing system. The dashboard switch has priority over the interval circuitry.
If the connections in your car aren't numbered, you can easily find the numbers with the help of a testlamp:
Connect one of the leads of the lamp to the negative of the accumulator (frame), and with the other lead you can test the terminals of the motor.
Put the dashboard switch in the OFF position. There is now only one terminal that makes the lamp go on 53a.
Put the dashboard switch in the low speed position. Now there are two terminals which make the lamp glow continuously: 53a, which we found already, and 53. There is a third terminal that makes the lamp go on, but where it is switched off every time the wipers are in their parking zone: this is terminal 31b.
Put the dashboard switch in the high speed position. Now the lamp is only lit at terminal 53b.
There is one terminal where the lamp never lights: the negative of the motor, 31.

Sometimes the dashboard switch is not connected in series with the positive, but on the contrary it is between the motor and the negative. The principle is the same, but connections 15 and 31 of the schematic diagram are interchanged.

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