Thursday, November 13, 2014

Yaesu FT-60 3.5mm Jack Breakout

Some more home etching fun on this one, 3D Printing too!

Along with computers and programming (just did PicoCTF, a hacking competition, SO much fun), I'm also into ham radio. My call is KB3ZKL if you want to give that a google. I have a page set up on QRZ for logging my radio contacts and a little bio info. But anyway, I have the good ole' Yaesu FT60 like a ton of other people do, and it has this cryptic little mic/speaker port on its side. Well, I guess its not all that cryptic, you can seen a pinout of it here courtesy of G4WPW:

But that little clone pin definitely is. Its set up mainly to 'clone' two radios when two have their 3.5mm jacks connected to each other directly. However, it can also be used to program and, to some extent, control the radio over some sort of serial protocol. This is where it gets cryptic, because there is absolutely no documentation on how it actually communicates. There are old circuits online for converting it to the old PC standard of Serial Ports with their +/-12 logic, but none actually explain whats going on it them. That being said, I've kinda run into a road block as far as that data part is concerned until I can procure a digital scope somehow to look at the data in all its raw binary signal form.

However, I still would like to be able to easily connect whatever headset and microphone I want to the device, maybe my own PTT key, and do it neatly. So, I decided to build a breakout board for the radio, giving me 2 standard 3.5mm jacks for headphones and a microphone. Also, for convienence, I'm going to build a PTT key right into the thing along with another audio jack for a simple external key. Here is the circuit I'm using:

Through a process of exporting that as an image, vectorizing it in InkScape, using a plugin there to convert it to an OpenSCAD file, exporting a very thin STL object, slicing that under special settings in my 3D Printer slicer, and finally tricking the printer into tracing out the lines on a blank board with a sharpie, I finally had my board ready to etch. Ha, yeah, it's convoluted, but its the only way I have without special UV sensitive compounds or a laser printer. I really should do a video on it. That being said it doesn't work too bad for this big stuff. After etching it like I did my first board I had my circuit:

Not too bad! I was quite happy with it. On too soldering up the components, and for whatever reason, just sitting down with the iron and soldering away is really relaxing to me. After about a half hour of total soldering I was done.

Notice the resistor I had to *ahem* bodge on after I had the board done. Its a shame cause I could have tried out my new SMD resistors too. Regardless, turns out regular mics have an impedance that's too high to actually trigger the radio into transmit on its own, so you have to add a path of lower resistance from the mic pin to ground in parallel with the microphone to get it to trigger. Eh, at least I got it flush and within the bounds of the board.

Once I get a 4-Pin 3.5mm male to male cable I'll be up and running, but initial test with the debugging pins prove the device works.

EDIT: 4-Pin cable arrived and the device works as expected with headphones and a microphone. Beautiful!