Intercom Lab

The Intercom Lab is an electronic kit manufactured in Israel by Powertech as part of the Tree of Knowledge series in 1979. There was also a Toplabs kit by Slinky Science, which was identical, but had slightly different graphics on the box. This kit is for children aged 10 and older and consists of ten project circuits, with the intercom being the main feature. It comes with a pair of plastic consoles allowing two children to play simultaneously each making an independent circuit. The kit does not require any previous knowledge of electronics or soldering because the construction of the circuit involves inserting wires and components into small pieces of breadboard.

Make Your Own Intercom Lab

All the project circuits use the LM324N integrated circuit (IC), which consists of quad low-power frequency-compensated operational amplifiers. This is a commonly used IC in electronics and found in modern instrumentation applications.

LM324N

Each console has an LM324N IC configured as an amplifier circuit. The output of the amplifier drives the loudspeaker in the opposing console. This is the basis of the intercom circuit.

In this intercom project, the loudspeaker also doubles as the microphone. Consequently, a switch configures the circuit for talking and listening modes.

Cost / eBay

This was a mass produced product cheaply manufactured in Israel. These kits often sell on eBay for a few pounds, and their price varies depending upon how complete it is. The IC is extremely low cost and can be replaced as well as any missing resistors and capacitors. If your syllabus consists of op-amps, then this kit may be of interest to you, perhaps as a GCSE project idea.

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