This is an article that I am very interested in. It is not so important to me to have the capability of using a microphone to transmit over FM, but, I want to try to build an FM transmitter to use as a remote control.
There are other uses of this circuit. It can be used to transmit any audio signal. It is basically the same as a Griffin iTrip. There is an inductor/capacitor oscillator that can be changed to change the transmitted frequency. It has a home made inductor, and a trimmer capacitor which can be changed to change the frequency. This project can be found at tacashi.tripod.com Article submitted by Utch
8 Responses to “DIY FM transmitter”
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Sweeeeet. Maybe I can get my garage door open with this.
You would have to find the exact frequency that your garage door works on, and would have to find out what kind of output your garage door opener is giving. You would prob. have to add a microcontroller to the circuit to output the serial data that you would need, but you are correct in that it should work. Assuming your garage door is operated on FM, which is most likely is.
Intriguing concept. Was thinking
of making a wireless microphone
out of’t. Plenty of range.
Anon, Don
You could easily do this. The frequencies are set for an FM radio though. If you wanted to use it for a sound system at like a church, you would have to build a receiver also, and find the correct frequency from the FCC. It would not be that hard, and could be done. Let me know if you get it to work.
Hi. Was looking to incorporate this into a speaker system where the transmitter
will be placed at the hi-fi side and the reciever would be built into the
speakers. Quite difficult to pull wires and messy, so why not go wireless. Do
you have a reciever circuit that would work with the transmitter? Regards
That’s a nice transmitter project! I was wondering whether the 2pf coupling capacitor gives you enough isolation from detuning when your hand gets near the antenna. This is a problem that I had when using a circuit like yours, but I didn’t have the capacitor.
With respect to walied’s question about a receiver - how about just using an FM broadcast receiver as the receiver? No need to make a receiver when they are already one of the most common consumer electronics products. And inexpensive at that.
How would you increase the power output of this? I’m curious as to how this kind of circuit works. Once you have this done, would it work as a sort of low power preamp, almost, so you could feed it’s radio frequency output into a power amp, into an antenna?
I guess I would need to look at regulations about broadcast power regulations before I built one of these on a large scale. I’m just wondering about how you would scale this up, and how a tuner, you know, tunes, and whether it would be possible to just amplify that.
What do i have to modify so that i can put my mp3 on it?