How to Make FM Transmitter

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Introduction: How to Make FM Transmitter

About: HI! I am Junez Riyaz, currently doing Bachelor of Technology in the field of Electronics and Communication Engineering. I am much interested in inventing something new yet from my childhood. In my leisure ti...

A short range FM transmitter is a low-power FM radio transmitter that broadcasts a signal from a portable audio device (such as an MP3 player) to a standard FM radio. Most of these transmitters plug into the device's headphone jack and then broadcast the signal over an FM broadcast band frequency, so that it can be picked up by any nearby radio. This allows portable audio devices to make use of the louder or better sound quality of a home audio system or car stereo without requiring a wired connection. Being low-powered, most transmitters typically have a short range of 100–300 feet (30–100 meters), depending on the quality of the receiver, obstructions and elevation. Typically they broadcast on any FM frequency from 87.5 to 108.0 MHz in most of the world . In this project we design the circuit in such a way that ,the circuit will collect the input through aux cable and broadcast with in FM frequency range. The broadcasted output can be collected with a FM radio.

Now I am going to instruct how to make a FM Transmitter with less number of components.

If you want how to make fm receiver click here for tutorial.

For more projects subscribe my youtube channel [Click Here]

Lets Get Started..

Step 1: Components Required

Transistors

2N3904 - 2 [ Banggood ]

Resistors [ Banggood ]

100k Ω - 1

100Ω - 1

1M Ω - 1

1k Ω - 1

10k Ω - 3

Inductors

0.1µH inductor (Air coil)

Capacitors [ Banggood ]

0.1µF - 2

40 pf trimmer - 1

4.7 pF - 1

10pF - 1

Other

Anetenna

9V battery and clip [ Banggood ]

PCB [ Banggood ]

Step 2: Circuiting

I attached the pcb layout , you can directly use this , to etch the pcb.

Fritzing file of circuit is attached.

Once the pcb is prepared, insert the components in to pcb according too circuit and solder it.

Now we need to make Inductor, Take a copper wire of 18 gauge or 22 gauge.

For 18 Gauge wire, form a inductor with 4-5 turns of 1/4 inch (or)

For 22 Gauge wire, form a inductor with 8-10 turns of 1/4 inch.

Now solder the Inductor to the circuit,

If you have antenna, solder it or take hook up wire of 8-10cm as antenna.

I used 3.5mm female audio jack , because we can frequently plugin mic,audio devices easily.

If you uses mic ,it senses the audio and broadcast to near by fm radio. It can also be used as spy bug.

Step 3: Making PCB

In this , I used permanent marker as protective coat for pcb.

Step 4: Tuning Transmitter

Now the time to tune the transmitter, which is very hard and time taken process. Be patience while tuning.

By varying the trimmer capacitor ,you can vary the transmission frequency.

Slowly vary the trimmer capacitor, then at a point you can hear some distortion in radio.

Then slowly vary in that area, when transmitter and receiver frequency matches you can get the clear output from radio.

By tuning the frequency , making of FM transmitter is completed.

For detailed construction check the video below.

Step 5: Construction and Testing

Feel free to comment.

For more projects subscribe my youtube channel [Click Here]

Sensors Contest 2017

Participated in the
Sensors Contest 2017

1 Person Made This Project!

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16 Discussions

1
SHOE0007
SHOE0007

4 months ago

Good little project. Have you worked with 555 timers? I have built a 555 timer Radio transmitter that can travel 50-60 feet min. With powerful transformers between the coil it may be able to trasmit farther than 60 feet. It was an amazing project to do.

FQP5A61JHUTV3RR.LARGE.jpg
0
bronyeg
bronyeg

Reply 8 weeks ago

hi can you share the components and the circuit diagram thanks

0
SHOE0007
SHOE0007

Reply 8 weeks ago

Sure. R1 was 460 ohms and R2 was 1 Kohm. Coil was from 130 in 1. You may need an old coil or an 130 ant coil from the 130 in 1 to get this to work.

0
SHOE0007
SHOE0007

Reply 8 weeks ago

A snaps ant coil would work well not as well as the 130 in 1 ant coil but if you cannot find it you can order parts from ebay.

0
MbaniM
MbaniM

1 year ago

Great work. But Can it be built without the trimmer capacitor? Thanks

0
ImperialR
ImperialR

Reply 7 months ago

you need trimmer capacitor to set the transmission signal frequency.

0
VaibhavR9
VaibhavR9

3 years ago

How do you make it work with a male 3.5mm pin???

0
MeemaM
MeemaM

Reply 1 year ago

I was only able to find a male jack with 4 rings. Would it be okay to connect left, right, and mic to the signal line?

What do you think would be the best connection to make?

Thanks!

0
JunezRiyaz
JunezRiyaz

Reply 3 years ago

just in place mic attach the 3.5mm pin

0
ShadyM1
ShadyM1

1 year ago

can i use 5v supply ??

0
the_electrode
the_electrode

1 year ago

I wanted to make a switch using this circuit for my room lights so if I just replace the mic with a push button then will it work or there is something else that I would have to do ?

0
DiS7
DiS7

1 year ago on Step 1

Capcitor kate voltage ko ho

0
DasurA
DasurA

2 years ago on Step 2

Hello sir i want buy this fm transmitter short range how many price

0
gustavio101
gustavio101

3 years ago

Hi! Could you please send me the formula you used for calculating the inductance of the coil, my wires have other diameters.

Also, is the formula working with the metric system?

0
the_3d6
the_3d6

3 years ago

Nice! Thanks for sharing

0
JunezRiyaz
JunezRiyaz

Reply 3 years ago

Thank you ..