Assemble the board according to the parts list and assembly print. Please observe in particular the following:
1) The elcas have to be inserted into the board in the right direction. The negative pole of the elca is marked with a bar.
2) The light-emitting diodes are to be placed into the board in the right direction. Please observe the drawing of the description with respect to the ”K” and ”A” connection.
3) As a matter of principle the IC’s have to be inserted into the IC-holder that has been soldered on the board last. Please make sure that the marking on the one side of the IC coincides with the corresponding imprint on the board!
4) The diodes and zener diodes are to inserted into the board in the right direction. One side of these components is marked with one or several rings (see drawing).
5) Place the watch module carefully on the board according to the drawing and connect the 5 connecting cables with the board as per the drawing.
6) Connect the receiver board with the watch board according to the drawing by using short wires.
7) Connect the receiving module with the board according to the drawing, too, by using very short wires. The receiving module has a built-in infrared filter. In case of strong solar radiation, it may still happen that sunlight affects the receiver. In this case, you have to stick a tube that is black on the inside, Ø 10 mm, approx. 3 cm (not enclosed) in front of the eye of the receiving module. This will prevent that sunlight shines on the receiver from above. Now the infrared light can hit the receiving module horizontally only. This tube must also be placed in front of the receiving module when timing small bodies (e.g. model cars) etc. In case of small bodies, the infrared rays of the transmitter may be reflected by other objects in the room and then the watch does not react when the small model car drives past. After placing the tube, no reflections may hit the receiver at the side. The disadvantage of the tube placed upon is that the range of the light barrier will be reduced.
8) The kit is intended for battery operation. Please use powerful batteries, preferably one battery holder each with 6 alkaline round cells. These have a life of > 6 hours! When using the case recommended by us, the battery holder fits into the case of the transmitter. The battery holder does not fit into the case of the receiver. Here the battery holder is to be mounted outside the case.

There are 4 push-buttons on the board to operate the stopwatch and the infrared receiver. The functions of the single keys are:
S1: When operating the light barrier (interruption), a flip connection is triggered which stops the watch and stays in that position (so that the watch does not start and stop again uncontrollably through new movements in the range of the light barrier). The flip connection will be reset when pressing the key S1 and the light barrier is in receive position again and can trigger the stopwatch (start or stop) again.
S2: When pressing this key, the stopwatch may be either started or stopped by hand.
S3: Delete display (set the stopwatch to zero). Only possible if stopped with S2 before.
S4: Change-over of the watch module: ”normal watch operation / stopwatch mode”. Simple stop watch operation with light barrier:
1) Assemble the receiver and transmitter in such a manner that the rounded points of the infrared LED’s of the transmitter point as exactly as possible to the round window of the receiving module. The distance between the transmitter and receiver should be approx. 2 m. 2) Turn the transmitter on.
3) Turn the receiver on.
4) The display of the watch shows ”I I”
5) Press key ”S1”. Now the watch is in normal watch mode.
6) Press key ”S4”. Now the watch is in stopwatch mode and can be operated through the light barrier.
7) Now you may start the stopwatch by hand by pressing ”S2” and do the timing by interrupting the ray of light of the light barrier. The light barrier must not be covered at the start, but only during the finishing order! Now the display indicates the time.
8) For a new start please press ”S3” to delete the display. Then ”S1” to ready the light barrier receiver again. Now you may do the timing again as described under 7.
9) You may also start the stopwatch per light barrier (flying start) and stop it by hand. For this purpose please proceed as described in 1. to 6. and continue as follows:
If the light barrier is operated now (interrupted through a sportsman), the stopwatch starts. Then press ”S1” and stop the watch by hand with ”S2”.
If you want to repeat the process, press ”S3” to delete the display and ”S1” to turn the light barrier on.
10) It is also possible to start the stopwatch with the light barrier during a circuit with a ”flying” start” and to do the timing with the light barrier after several laps. For this purpose, please proceed as described under 1...6. If the light barrier is interrupted now, the stopwatch starts. Now wait until the timing at the finish shall be done (if several laps shall be run during which the light barrier shall not react). If now the timing is to be done at the finish, press the key ”S1” to activate the receiver. The watch stops, if the light barrier is interrupted now.
General note: If you press any keys twice in between or other keys than earmarked by mistake, the watch may switch to another mode (other watch functions). In this case switch off the battery for approx. 10 minutes and start anew as described.
Legal note: The quartz watch module employed for timing is not appropriate for verification. For this reason it is not allowed to use this stopwatch for official sporting events! Furthermore, this kit has no CE-admission as children’s toys! (It contains among others small pieces which can be swallowed, etc.). Therefore, children under 14 years of age may only assemble and operate this light barrier under supervision of a competent adult!

Fitting cases:
Transmitter: KEMO G081
Receiver: KEMO G091
Price group 10

Operating voltage + current: transmitter: 9V=, < 100mA, receiver with watch:<9V= < 50mA
Range of the light barrier: approx. 8 m
Display: < 30 min. resolution up to 1/100 sec., > 30 min. resolution 1 sec.
Dimensions: Receiver board E1: approx. 54 x 25 mm
Watch board E2: approx. 79 x 54 mm
Transmitter board: approx. 54 x 28 mm

Circuit description

The system consists of an infrared transmitter, an infrared receiver and an LCD watch module as it is employed for wristwatches, too. The watch module is put into stopwatch mode with the push-buttons. Then the connected light barrier receiver may stop or start the watch depending on the adjusted mode. If the infrared light ray of the infrared light barrier is interrupted, the receiver transmits an impulse to the watch.

Safety instructions for B232

These operating instructions belong to this product. They contain important instructions for operation and handling. Please keep this in mind when passing the product on to another person.
This kit is not intended for persons under 14 years (it has no CE approval as a children's toy).
Never expose this kit to high temperatures, strong vibrations or humidity.
Setting into operation has to be done by adequate qualified personnel in order to guarantee the safe operation of this product. The operating voltage may only be drawn from a battery.
The regulations for prevention of accidents for electrical installations and operating material of the industrial employer's liability insurance association are to be observed in industrial facilities.
In schools, training centers and do-it-yourself workshops, the operation of this appliance is to be supervised reliably by trained personnel. Never place the appliance close to combustible or inflammable materials (e.g. curtains).
We do not assume any liability for material damage or personal injury caused by non-compliance with the operating instructions and these safety instructions as well as for its consequential damage.

Intended use

To do the timing at sporting events, like e.g. horseracing, car races, runners, etc. whose times may be recorded with the infrared light barrier.

Maintenance + Disposal

This kit is maintenance-free. If this device has to be disposed of one day, please hand it over to the special waste collection where ”electronic systems” are collected, i.e. where computers, television sets etc. are disposed of, too. Please do not dispose of with the household waste!