INTERNAL FM TRANSMITTER MOD

It would be cool to have a ultra-portable computer with a FM transmitter for roadtrips, etc. The smallest transmitter I found was a AirPlay adapter for iPods. It has a regular audio-jack and an additional 4-pin side-plug for power and serial data. The transmitter is not connected to the USB hub and runs off 3.3v. To change frequency I de-soldered the buttons and mounted them on a tiny PCB-board and placed it in the memory expansion bay.

The pinout for the iPod headphone jack can be found on pinouts.ru (on the right-side).

It was quite hard to crack the case and I had to destroy the case to get the board out.

The display is to tune the frequency to transmit on and two buttons to adjust in .5 steps.

Space is limited and I stripped the display and buttons to make it as low profile as possible.

The installation is done in three steps; antenna, audio input, and buttons.

With limited space in the display bezel, the antenna could only be mounted on the right side. Removing the old cable and routing a new multi-strain cable from the left side of the motherboard, under the display, and up on the right side of the display.

It fits perfectly and still some free space for the front panel.

I had to probe the audio-jack on the Eee motherboard to figure out the audio left, right, and ground points. From front-to-back in the middle of the picture, ignore the three wires to the left: audio left, audio right, and audio ground.

The Airplay display had to be removed and frequency changing is done blindly. To be able to adjust the freqency, I had to move the buttons to the expansion bay. I found a piece of prototyping board, mounted the two switches, and soldered two wires from the Airplay board back to the expansion bay where I placed the prototyping board. One side of the switches is ground and the other for plus and minus signal. The frequency is changed up or down when the signal is low (ground).

And the main unit could only fit in the empty space between the DC-power and ethernet/modem-jacks. Pretty much a perfect spot.

No problem with height, it might touch the bottom of the case but it's hard to inspect.

 

Source: http://beta.ivancover.com/wiki/index.php/Eee_PC_Internal_Upgrades