Introduction: How to Operate Niftymitter V0.24

This instructable will tell you how to operate Niftymitter 0.24, a small open source FM transmitter. More information on the design can be found at www.openthing.org/products/niftymitter.

This transmitter is in development and has not yet been approved by any regulators. It is a low power transmitter and works over a very short range - please ensure that by using it you are not interfering with any other nearby transmitters.

Step 1: Plug in a Source

Plug in any audio source into the 3.5mm jack socket. Set the volume on your source as low as possible.

Step 2: Switch On

Switch the transmitter on.

Step 3: Tune In

Make sure your transmitter and radio receiver are at least 2m apart to avoid tuning in to a harmonic frequency. Switch on your radio and tune the radio in to the transmitter. This should be broadcasting on a frequency between 88 and 91 MHz FM, transmitting silence.

It is difficult to be accurate here as: a) the frequency can very depending on atmospheric conditions and b) the scale on your radio might be calibrated differently to the scale on my radio, so would give a different reading of what frequency it is receiving on.

If you are having difficulty tuning in, you may need to retune the transmitter, which is described in step 5.
 

Step 4: Turn It Up!

Carefully turn up the volume on your audio source to a comfortable level. If you turn up too loud, the signal will sound distorted (it really doesn't need to to be very loud).

Step 5: To Retune Niftymitter

Slide out the circuit box.

Use a small 3mm slot headed screwdriver to adjust the 'trimcap'. It is best to use a screw driver with an insulated handle to minimise interference with the transmitting frequency, or ideally a trimtool such as this one from Rapid.
The trimcap is a small brass coloured component accessed by the hole marked 'tuning'. Clockwise for up, andticlockwise for down, it only requires very fine adjustment.
 

Step 6: To Replace the Battery

Slide out the battery tray. Unclip the battery from the PP3 clip, recycle/recharge and replace.

Comments

author
ericb1 made it! (author)2011-05-22

does this transmit in stereo or mono? thanks!

author
royshearer made it! (author)royshearer2011-05-22

This transmits in mono. The current version mixes a stereo pair into a mono broadcast.

author
ericb1 made it! (author)ericb12011-05-22

Hmm, is there anything out there that transmits in stereo? I was looking at this: http://makeprojects.com/Project/Micro-FM-Transmitter/721/1

but that doesn't say whether it's in mono or stereo, so I'm guessing it's stereo?

otherwise it's just what I was looking for. :(

thanks

author
royshearer made it! (author)2009-12-14

Don't worry, I'm working on it!

author
terminatordoink made it! (author)terminatordoink2010-02-05

 its February  6, and we are still waiting for the proper instructable on how to build this. This is interesting but lack intructions 

author
royshearer made it! (author)royshearer2010-02-08

The project website is at www.openthing.org with links to the source files, and there are two instructables up explaining the assembly:
https://www.instructables.com/id/Assembling-a-Niftymitter-v024/
https://www.instructables.com/id/Assembling-a-Niftymitter-board-a-short-range-FM-/
These were posted in December, sorry if you missed them.

author
bwpatton1 made it! (author)2009-12-12

I agree with lemonie, please post an instructable on how to build this.
Thanks

author
lemonie made it! (author)2009-12-11

Could you not show us how to assemble it as well?

L

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Bio: I am a freelance design engineer and drummer. My business site is at http://www.zero-waste.co.uk and is often concerned with appropriate technologies ... More »
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