Manual

Project 159 Floor-to-Ceiling
Break the Beam
This circuit is similar to project 29.
Assembly (adult supervision recommended):
1. Place base grid supports on base grid A.
2. Place parts on base grids B, & D, and install into base
grid supports on grid A. The pegs should be facing
inward.
3. Mount grid C on top of grids B & D using 4 stabilizers,
attaching the 2 vertical snap wires (V1) as you do it.
4. Place the remaining parts on grids A & C.
5. Place the Q4 attachment on the phototransistor (Q4).
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Turn on the slide switch (S1) to light the white
LED (D6). Place your hand between the white
LED and the phototransistor (Q4) and an alarm
should sound. See if you can move your hand
through the “box” without activating the alarm.