Author Options:

usb to fm transmitter Answered


I am a very big noob to wiring.
For a present, I wanted to make my cheap old AAA powered fm transmitter into a usb powered one. 
Thinking I was so smart, I cut up an old usb cord and soldered the red to positive and black to negative.
It worked great until it started melting the transmitter. 
So I now I realize that usb is much more powerful than 2 AAAs.  heh heh.

I found this:

but it's a bit over my head.  I'm assuming I need to get a capacitor or voltage divider but I could use a little help breaking it down into noob speak.  Plus the transmitter is a little thing, 2 inches, is there a smaller way of checking the voltage?

K, thanks bye!

3 Replies

Jayefuu (author)2010-03-21

So you have 5V and you want 3Vish?

This should do the job. It's used on a pcb I own for converting 5V to 3.3V for an SD card reader. You'll also need 2 x 1μF ceramic capacitors to stabilise the input and output voltages. Page 2 of the data sheet shows you how to use them.

That solve your problem? :D

Select as Best AnswerUndo Best Answer

audrywolters (author)Jayefuu2010-03-21

Thanks!  Looks perfect!  Very small and right voltage.

But I looked at the data sheet and it all went over my head
Could you tell me what I'm to solder to what?

I think I get that the usb goes to the middle prong (Vin)
and Vout would go to the board
but what is the GND?
and where to the capacitors go?  one to + and one to - but which side?

Sorry, total newbie.


Select as Best AnswerUndo Best Answer


 Oh, capacitors go on both ends!
But how... where... i not know  *-*

Select as Best AnswerUndo Best Answer