Radio

I was very interested in making my own radio. If you think for a minute, you could understand how amazing this technology is. It consists of two main parts - transmitter and reciever. Firstly, the transmitter generates an electrical signal, which is then modulated to encode the information to be transmitted. This modulated signal is fed to an antenna, which emits electromagnetic waves. Then the receiver picks up radio waves using its antenna. In the receiver, the reverse process occurs - the waves are converted into an electrical signal. Finally, this signal is cleaned of noise and interference, then demodulated to extract the original information and it's reproduced in a speaker.

In this project we don't have a very large list of components that we need.

PASSIVE ELEMENTS:

R1 - 10k

R2 - 22k

R3 - 10

RP3 - 22k

C1 - 220pF

C2 - 330pF

C3 - 100nF

C4 - 220pF

C5 - 150pF

C6 - 3.3nF

C7 - 330pF

C8 - 47-141pF (I just used three 47pF capacitors in parallel, but this value is changeable as it controlls recieved frequency, so you can experiment and try different values)

C9 - 100nF

C10 - 22nF

C11 - 10nF

C12 - 3.3nF

C13 - 180pF

C14 - 2.2nF

C15 - 2.2nF

C18 - 100nF

C19 - 180pF

C20 - 100nF

U10 - 4.7uF

U11 - 470uF

U5.1 - 7-20pF (You can use variable capacitor with bigger range)

C17 (inductor coil) - 56nH

Antenna

Speaker

ACTIVE ELEMENTS:

Battery 9V

TDA7000 (FM reciever)

LM386 (Amplifier)

The circuit is pretty simple. TDA7000 does main job. All you need is to connect it according to datasheet, which is the second picture.Then output signal goes on amplifier LM386 and then this signal goes to the speaker. As I have already mentioned, you can adjust the value of capacitor C8. Try to experiment with different values.

It was pretty hard to find 56nH inductor coil, so I thought it's much easier to make one by yourself. I used 22AWG wire and removed isolation. Then you should use some cylindrical object (I used my pen) and wind copper. Make 6-7 skeins.

Now you can place all components on your breadboard. I'd like to warn you - don't place inductor coil near the variable capasitor like I did. It'll create a lot of noice while you try to adjuct capacity. You can also solder this project on ciruit board, but remember to not solder ICs straight away. They'll get damaged by the heat of soldering iron. Use IC holder.

Here you can see how the radio works. This is simple project, so I'm sure you'll be able to create such interesting technology by yourself!