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Instruments Required for Making a Walkie Talkie

A walkie-talkie, or homemade intercom, can be a simple enough project, provided you have the right materials on hand. Most parts needed for a DIY walkie-talkie are readily available in hardware and electronics retail stores, or even from old pieces of electronics lying around the house. A walkie-talkie consists of six basic parts: a transmitter, receiver, speaker, microphone, crystal (channels) and a power source. A homemade walkie-talkie will be slightly limited as to available channels, but will function nearly as well as a store-bought personal walkie-talkie.

Two Cordless Phones
- Because a cordless phone already has a transmitter, receiver, speaker, microphone and channels all built into a single unit, it plays the most important role in the project. A cordless phone normally communicates using radio waves to a base station, which is, in turn, physically connected to a telephone line. While a walkie-talkie does not require a telephone line, it does require communication between the cordless phones' bases.
In-Line Coupler
- In-line couplers are commonly used to connect multiple pieces of audio equipment to a single telephone line. For instance, a household that just wants to have easy access to the phone from different points in the house will use a coupler and add an extension, without needing a separate phone line. The in-line coupler will play much the same role in a walkie-talkie as in a phone extension, connecting the phone base stations and enabling direct communication between the handheld units.
9V Connector and 300-Ohm Resistor
- Unlike corded phones, cordless phones require that their base stations be powered by a battery. This is why the coupler must have a power source, as it would act as a charging station for the two base stations connected to it. Couplers, being passive devices used only to connect equipment with their own power sources, don't come equipped with battery connectors. The battery connector must therefore be soldered directly to the coupler's internal wiring. The resistor, connected in series between the battery connector and the coupler, acts as protection for the electronics.
Other Tools
- Miscellaneous tools needed for this project include wire nippers, for cutting and exposing the coupler's internal wiring, a soldering rod for securing the connection, some electrical tape for safety, a couple of phone cables, and a small cutting tool to carve out a small slit in the coupler for the connector's wires. A battery is also needed to hook up to the connector in order to power the base stations. It may be best to test the whole setup using two wall phones before connecting the base stations, just to ensure that it's working properly.

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