Introduction: Short Rage Wireless Music Transmitter
Now , i am with a short range wireless FM transmitter which can powered through USB. It can take audio signals and transmit it over a short . It's maximum rage is around 100- 150 meters.you can easily listen it over a radio . it's very cheap and easy to build.
Step 1: Fetching Parts
All you need are some common electronic components.
You can buy them at Radio Shack!
1. Transistor BC 548 OR 2N2219a.
2.Capacitors : 1n , 1n , 10p , 10p variable , 1uF electrolytic.
3. Resistors : 2k7 or 2.7 k , 1k , 10k , 10 variable.
4. Inductor : you can make by yourself . 7 turns on 3mm or 6 turns3mm.
5. Battery : 9 volt .
6. PCB you have to make one or use breadboard.
7. Antenna 10 cm long!
8. Nothing else
Step 2: Circuit Diagram
Here is the simple circuit diagram!
Step 3: PCB - LAYOUT
Here is the PCB layout.
In the next PCB the red ones are capacitors , green ones are resistors , brown one is variable resistor , white one is transistor , yellow one is inductor and other holes are for power and input and antenna. TO make this PCB at home you have to follow this link : ""https://www.instructables.com/id/DIY-Printed-circuit-board/"".
Step 4: Finished Product
HERE is the finished product!

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18 Comments
7 years ago
this looks great, but it's just one audio channel, right?
8 years ago on Introduction
Wow, that's was exactly what I want. How far can it transmits. And what's the inductor's inductance. Forgive me if I am disturbing you.
(I think my English isn't well :) )
Reply 8 years ago on Introduction
And don't mess with inductor just make it as said cause i don't remember it!
Reply 8 years ago on Introduction
But I still don't know what is the wire's diametre. You couldn't make it without having this number in mind, right.
Reply 8 years ago on Introduction
Well it's nearly a whole house (not if your house is full of complex radio frequencies and disturbances). It's like 5-10 meters.
8 years ago on Introduction
hey.. firstly i want to thank you for this amazing build.. i wanted to know how much power does it transmit over the antenna.. because in my country, transmitting over 500mA is considered illegal and i don't wanna break any rules.
thanks..
Reply 8 years ago on Introduction
No worries it's way down that that range may be one or two houses.
9 years ago
What is the USB plug for? it is not on the diagram, it can not be for power as that is 9V.
9 years ago on Step 2
sorry to bother u.. are we using variable resistor too? if yes, we r varying both resistor and capacitor at a time to set a frequency?
Reply 9 years ago on Step 2
no! the variable resistor is for controlling the volume! to change frequency you have to change the capacitance of the variable capacitor!
9 years ago on Introduction
u didnt mentioned the range of frequencies it is transmitting
Reply 9 years ago on Introduction
You are right because the frequency is variable you can tune it by C2 capacitor!
Reply 9 years ago on Introduction
it is not a receiver(a receiver can be tuned).. its a transmitter.. so it should emit with some fixed frequency.. and how to tune it?with physical means?
Reply 9 years ago on Introduction
Oh dear lord! Let me explain this: The receiver circuit given in this instructable does not have a fixed transmitting frequency. The frequency of transmission can be controlled by changing the value of C2 which is a variable capacitor ! Just change the value of the capacitor and the frequency of transmission changes respectively.
Hope this clears you doubt if not tell me and explain your problem well!
Thanks for Commenting!
I like people who make me angry by asking questions!
9 years ago on Step 3
Can you be more specific with the remaining holes? What exactly goes to what? Thanks
Reply 9 years ago on Step 3
The holes that are circled in purple? Just need some clarification
Reply 9 years ago on Introduction
Some of the holes are for the USB 2.0 male jack for getting power and antennas and other power supplies!
9 years ago on Step 4
Very cool and well done. This is a very useful item.
Thanks.