iPod, Sat Nav or Both??

I managed to take the car out for a spin last weekend and had my 'in ears' (headphones) plugged in to the iPod as usual.  If you have read, or at least skimmed through, the blog you will know that I have built in the iPod and also built in the Sat Nav.

This is all well and good but when you are using the Sat Nav for directions, you can't hear the instructions over the music and the general noise in the car.  I needed to find a solution that wasn't going to cost me a lot of money and would give me the best of both worlds.

The first thing to consider was an all in one unit.  After a lot of research, the only Sat Nav unit I could find with a headphone socket that came close to what I wanted was the Garmin 2585TV which is a Sat Nav with TV tuner and can play MP3s etc.  However at £250 it was not really an option.  Anyway, I already have a Sat Nav and an Mp3 player so what is the point.  I needed a way of hearing the Sat Nav in my 'in ears' along with my music.

I decided that the only way was to get the soldering iron out and make up a one off cable to do the job.  Now first off, I must apologise that I didn't take any photos of the process, so my words will have to do.

I needed a mono out from the Sat Nav to link to a stereo out on the iPod to the stereo in on the 'in ears'. First job to tackle was the Sat Nav.  On YouTube you can find numerous videos of how to replace the battery on a Sat Nav and I used one of these to show me how to get in to the unit.  Once in, with it suitably dismantled, I unplugged the speaker plug from the circuit board and cut the wires.  I then soldered on some single core speaker wire.  I drilled a small hole in the outer casing of the Sat Nav for the cable to be passed through and set about putting it all back together.  This was an easier process than I thought it was going to be and within about 30 minutes the whole process was done.

Wiring up was straight forward.  Take a cable with a stereo plug for the iPod and cut one end of it off.  Each side will have an inner cable and an outer cable.  Twist and join the outer cable from both sides so you end up with a single outer, a single red and a single white cable.   Do the same with a cable to go to the 'in ears'.  Next join the red to the red, the white to the white and the out to the out on the 2 cables.  Check at this point that it is all working.  Finally add the left and the right from the Sat Nav cable to the red and the white of the combined cable and check again.  I now have music in stereo from the iPod and instructions over the top from the Sat Nav.  Finally solder all the joints, insulate and bind it all together with tape.  Job done.

Final job was to fit it all back in the car.  At the same time I took the opportunity to change the charger option for the Sat Nav so it uses a USB cable and not a hard wired cable.  This is so I can plug the Sat Nav in to a laptop for updates as they are required.  The iPod already has this type of cable so I can update the content without having to dismantle the car each time.

So there you go.  A simple job.  Total cost, including a new soldering iron, £20.  And it took about 3 hours total time including taking the car apart and putting it back together.  Just need to get the volume levels right on the road and for that, I need some more good weather to take the car out!!

UPDATE 17th Feb 2013

So, finally, a decent day to take the car out and see what the finished product is like.  I set off with neither iPod nor Sat Nav on, as neither had any charge in them, so I knew I needed a good run to put some charge in them.  At a convenient point, I pulled over and set about putting in the 'in ears' and switched on the Sat Nav.  First thing was it couldn't get a GPS signal.  That has worked in the past, but has never been 100%.  Anyway, I turned on the iPod and ..... nothing .... well a lot of static and nothing else.  Disappointed, I carried on on my journey and went home.

My wiring had worked on the bench, but the real world test had failed miserably.  I suspect it was a combination of the location of the Sat Nav and the fuse box and electricity etc causing the interference, which, of course, I didn't have on the bench.

So, the conclusion.  Unless you are some sort of electrical genius and understand these things and are prepared to spend some money on posh kit, stick with the Sat Nav mounted to the window!  It is now back to the way it was before for a while,and I think that is where it is going to stay. I have admitted defeat!!!