How to build an FM transmitter with arduino?

Question

Dear: Element 14

You may remember me from my last post. I was trying to build an FM transmitter between 108 and 88 MHz when I ran into a few problems with my 555 timer. Now I have solved those problems and are running into more. You see I have successfully built a radio transmitter of my own design but it only emits AM not FM waves. It also has a rather short range of a 12 inches which is another problem I could have advice with. It also has a problem with tuning by only letting me change the pitch not the station so could I please have some help. Look at the circuit diagram below for questions on my schematic.

From: Noah

shabaz · Accepted Answer

The circuit doesn't make sense : ( It would take a book-worth of typing here (a few hundred pages of text) to explain the function of the parts, and how they may be applied into a circuit.

For example, when you see something on forums like "a transistor is a switch" that is a very crude approximation (that works some of the time, and saves typing a hundred pages) - but won't meet your needs, which appear to be to design custom circuits from scratch.

To summarize, one can't design a complex circuit from scratch without the theory. I can suggest good general electronics books if you'd like that approach.

The other alternative is to find a circuit that is already advertised as providing the function you need, and tweak it slightly and observe the effect (i.e. create a working prototype and then modify it slightly). Most people try to find existing known working building blocks.

If you want to pursue that method, there are hundreds of sites showing FM transmitter circuits, just pick a reputable looking site (there are some

garbage sites out there too, with nonsense circuits). Again, many people here can provide recommendations if this is what you decide you want.

Many people use a combination of theory and practical circuits books, to learn some basics, but at the same time get some practical experience too, following and copying circuits at the start (for a few years).

How to build an FM transmitter with arduino?

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