How to make a simple radio transmitter and receiver

Required materials: a square wooden board (the same size as the palm), a 6V laminated battery, a flashlight bulb (or a 6V motorcycle steering bulb), a reset button switch (an old doorbell button), several self-tapping screws, several wires, a roll of double-sided adhesive tape and a thin iron wire.

The manufacturing steps are as follows:

1. Stick the battery on one corner of the template with double-sided tape;

2. Fix the key switch (code key) in the center of the template with self-tapping screws;

3. After the electrode of the bulb is welded with iron wire, it is fixed on the empty position of the board with thin iron wire and self-tapping screw;

Finally, all the batteries, switches and light bulbs are connected in series, and a simplest transmitter is made. Principle: When the button switch is pressed and released instantly, the battery current will light or extinguish the small light bulb through the loop, and the radio can receive the instantaneous current pulse signal. When the receiving frequency of the radio is adjusted properly, the effect will be better.