Building A Custom Interface For Surplus HF Radios

July 26, 2012 by Mike Szczys 12 Comments

[PRC148] picked up a Motorola Micom radio from eBay. These are US State Department surplus, but apparently the 125 Watt HF units are top-of-the-line at a tenth of the sticker price. The one hangup is that they’re headless; you can’t control them without additional hardware. But the Internets are often kind to the hobbyists, and this is no exception. You can get software to run the radio from a PC thanks to the Micom Yahoo Group. [PRC148] took that software as an example and built his own stand-alone interface. [Cached version of the page]

The head unit is an Arduino driving a four-line LCD display and a rather large array of buttons. The forum thread linked above shows his humble beginnings on a breadboard. During the project [PRC148] learned a lot of skills to end up with what you see above. Hiding behind the reused bezel is a PCB he designed in Eagle CAD and etched himself. It allowed him to cram the tactile switches close enough to work with the button overlay on this keypad.

UPDATE: The traffic from this feature took down the forum hosting the content. They requested that we do not link to them because of this. A cached version without images can be found above thanks to [Termm].

Dash-mounted Nook Color Is A Perfect Head Unit Replacement

December 5, 2011 by Mike Nathan 30 Comments

jeep-nook-mount

XDA forum member [craigbru] wanted to beef up the audio setup in his Jeep, and thought that his Nook Color would make a suitable replacement. Since he jailbroke the e-reader, the head unit upgrade lets him do just about anything you can imagine, all from the comfort of the driver’s seat.

Seeing that he would continue to go off-road with the Jeep, he wanted to construct a mounting solution that was convenient and sturdy – something we think he did very well.

The dock was constructed using a Quadratec iVault stereo mount, along with a plastic tablet mount he had on hand. Because convenience was a primary goal, he put together a quick release charging solution as well as a simple audio interface using a set of touch contacts. This allows him to connect and detach the tablet from the Jeep without having to fuss with a bunch of cables each time. He also added an audio equalizer along with a Bluetooth OBDII interface to the setup, allowing him to tweak his tunes and monitor his engine with ease.

We think it’s a great-looking setup, and we’d be lying if we said we didn’t want one as well.

[Thanks, MS3FGX]

The Rube-Goldberg Of Car Audio

November 1, 2011 by Mike Szczys 14 Comments

[Anthony Pray] had his car stereo stolen. When thinking about replacing it he realized the he and his wife never used it for anything other than an Auxiliary connection to play songs from their cellphones. So instead of buying a head unit he pulled an unused home audio amplifier out of a dark corner of his house and wired it to the car speakers. Problem solved, except that the under-dash installation meant the only volume control is on the phone playing the audio. He decided to build a wireless audio controller that would let him send commands to the phone without quite as much distraction from the road.

The device you see above is his creation. What a beauty. But seriously, it’s so random and hacked together how can you not love it? And, it works!

The frame is made from plastic coat hangers, and the wheel is an old RC control knob. There’s even a play/pause feature built from the clicking properties of a retractable ball-point pen. A Cypress PSoC board reads the knob and pen positions, then pushes commands via a Bluetooth module in order to control the phone. He recorded a testing video (after the break) which gives you a better look at the functionality of this setup. Continue reading “The Rube-Goldberg Of Car Audio” →

2005 Subaru Aux-in Hacking

June 27, 2011 by Mike Nathan 32 Comments

2005_subaru_outback_aux_in

The CD player in [mukmuk’s] 2005 Subaru Outback gave up the ghost, and faced with a long road trip ahead of him, he was desperate to find a way to listen to something other than static-filled radio. He considered a 3rd party auxiliary input solution, but after seeing a similar aux-in hack here, he figured he could give it a go himself.

The stereo head unit design was changed between the 2004 and 2005 model years, so while he had a good idea of what to look for, he had to find the proper components on his own. Once he identified the radio module, he was able to locate the left an right input pins through trial and error. He carefully soldered a 3.5” audio jack to the head unit’s input lines, wiring it to cut off the audio signal from the radio whenever his Zune was plugged in.

Everything was reassembled, and the input jack was inconspicuously mounted in a cubby hole just above the stereo. [mukmuk] is quite happy with his modification, and we’re guessing his road trip was far more pleasurable as a result of his work.

More Car Audio Input Hacking

August 15, 2010 by Mike Szczys 19 Comments

[Dave] pulled the head unit out of his dashboard to add an iPod input. He took a much more invasive route than the other hack we saw a few days ago. He actually patched into the audio lines going from the Dolby reader head chip to the amplifier.

The first step was to trick the deck into thinking it had a cassette inserted. He scoped an enable pin on one of the chips to discover the timing and emulated that signal using a PIC microprocessor. From there he popped off the chip that reads the tape data, patching directly into the audio out traces. This presented some noise issues when charging the iPod but [Dave] fixed that with some decoupling capacitors.