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Assembly and Operating Instructions for Kits


Assembly Instructions for the Interrupter Photogate Cable Kit


Assembly instructions for other kits


This cable is used with the Multi-Trigger Breadboard.


Interrupter photogate cable (for Multi-Trigger Breadboard)


Photo 1


Photo 2

About the interrupter cable

interrupter pinsThe interrupter cable houses the infrared emitter and detector in a single U-shaped piece of plastic shown in Photo 1 to left. The posts of the interrupter have the symbols and shown in the graphic to the right. These symbols refer to the LED and phototransistor (PT) respectively. The numbers refer to the legs on the underside (not shown). We'll use the numbers to identify the 4 pins in the wiring instructions.


Since the pins on the interrupter are very short, the component will be mounted on the section of PC board shown in Photo 2. These and the other components in the kit are listed below:

  • 3-conductor cable, 3-ft length
  • Interrupter
  • PCB board
  • 3-in length of 3/32-in heat shrink tubing (HST)
  • 2-in lengths each of green and black hook up wire
  • 4-in length of red hook up wire

Tools that you'll need include a wire stripper, 15-30 W soldering iron, and solder. You will also need a drill motor and 1/8-in bit if you drill holes as described in the next step.

Photo 3

Drilling holes in the PCB


You may find it helpful for mounting the completed unit to drill 1/8-in holes in each end of the PC board. If you do this, place the PC board on a piece of scrap wood, so that the drill bit will pass into the wood below the plastic. This will prevent damaging the brittle plastic.


Photo 4

Photo 5

Mounting the interrupter


In preparation for soldering, place the interrupter on the PCB as shown to the left and tape in place. The numbers that are overlaid on the photo correspond to those in the previous graphic.



Photo 5 shows the under side of the PCB after the 4 pins have been soldered. Be careful not to create solder bridges between pins. If this happens, run the tip of the hot iron through the bridge to remove it. Remove the tape after soldering.

Photo 6

Photo 7

Adding wires to the board


Cut the red hook up wire into two equal, 2-in pieces. Cut one of these pieces into sections to connect the pairs of holes shown in Photo 6.



Photo 7 shows the under side of the PCB with the wires soldered in place.

Photo 8

Photo 9

Photo 10

Connections for the breadboard


We move to the gray, 3-conductor cable next. Strip the gray insulation back 2 inches. Then strip the the individual red, green, and black conductors by 3/4 inch. Next, strip 2-in sections each of the red, green and black hook up wire to a distance of 3/4 inch. Wrap the stripped ends of the photogate cable conductors around these 2-in extensions as shown in Photo 8.






Solder the connections as shown in Photo 9.







Slip 1-in sections of heat-shrink tubing over the bare connections and heat to shrink. Then strip the ends back by 1/4 inch. See Photo 10. These are the wires that will connect to the breadboard.

Photo 11

Stripping the other end of the cable


At the other end of the 3-conductor cable, strip the outer, gray casing back by 2 inches. Then strip each of the red, green, and black conductors back by 1/4 inch. These are the stripped ends that will be used to connect to the PCB.


Photo 12


Photo 13

Connecting the cable to the PCB


Solder the stripped ends from the previous step to the holes shown in the PCB in Photo 12.






The soldered connections on the under side of the board are shown in Photo 13.

Photo 14

Photo 15

Completed views


Photo 14 shows a close up of the interrupter end of the cable. Photo 15 shows the entire cable. For instructions on how to connect it to the breadboard, see the instructions for your breadboard kit. The Multi-Trigger (v11) instructions are here.




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