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Build and install your own AUX Cable!

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sk93
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Re: Build and install your own AUX Cable!

Post by sk93 » Thu Feb 04, 2010 9:28 am

sk93 wrote:however, looking at the backside of my radio at the time, I was certain the pin numbering on the radio started from the bottom left pin being number 1, and the top right pin being number 12.
wheras in the pinout i posted for you counts from the top left to bottom right.
and yet I was wrong :)

I've whipped it back out this morning and the second schematic is correct.. the numbering is from top left, to bottom right.
I've now updated the schematic for the wiring and also updated the original post to reflect this :)

cheers!
:zzzz:

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Re: Build and install your own AUX Cable!

Post by Siftah » Thu Feb 04, 2010 2:31 pm

sk93 wrote:the caps are used to filter out some of the noise that can/will be generated along the cable.
they are also used to help maintain a constant "volume" in.
I tried without them, and although the cable worked, it wasn't very good.
Ahh, that concurs with what I read - I'll be using a Line-In source so I think I can get away with out them, my understanding is that the capacitors are more relevant for using a headphone level source. As I've gone ahead and already soldered up the cable I'll give it another go with the smaller pins this afternoon and see how it sounds.

(For info: I'm using the line-out port from my TomTom mount for the iPhone 3GS. This takes a Line-level output from the iPod Dock connector on the bottom of the iPhone, so I should be OK to skip the capacitors and get a slightly cleaner sound.)
sk93 wrote: I've whipped it back out this morning and the second schematic is correct.. the numbering is from top left, to bottom right.
I've now updated the schematic for the wiring and also updated the original post to reflect this
\o/ This is the most complete and best photographed documentation I found on the web, so I'm happy to have helped make it even better :)
sk93 wrote: It's likely the connectors aren't holding the pins - have you any reset/power switches you can "recycle"?
However, if you can take a piccie of where you've connected up your cable to the stereo, I may be able to spot what's wrong?
After my post last night I found an old USB header cable which I butchered and used those pins instead, soldering them into my cable. I've photographed it to document it on here later, but as yet I've not managed to test it on the car (my day-job is interfering with my car modifications!). I'm hopeful these will work better and they'll certainly fit into the connector better as far as I can tell.

(I'm adding pins into an existing plug, rather than just adding pins to the open connector, so I'm unable to use the single header pin cables but rather extract the metal plug from the plastic casing then insert it into the existing plastic plug - I'll document this later with photographs as it's difficult to explain!)

:)

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sk93
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Re: Build and install your own AUX Cable!

Post by sk93 » Thu Feb 04, 2010 3:20 pm

i know exactly what you're on about in your final paragraph.
Ideally, I'd have liked to have a plug already there on mine.

I'm planning to retro BT later in the year, so I'll be taking more photos and expanding this guide then, but if you can beat me to it :D

you're sort-of correct with the lineout theory. It will certainly have less volume issues, but you are still likely to get noise, based on all the jacks and sockets along the route.. tbh though, you may never notice it, so give it a whirl without - it's only a five minute job to add them in later if needsbe :D


the USB header pins are a perfect fit btw ;)
:zzzz:

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Re: Build and install your own AUX Cable!

Post by Kaide » Sat Feb 06, 2010 6:39 pm

I'm having trouble finding the required parts... I cant find any .6w resistors here... Is there an equivalent in the States?

Also, I was thinking, instead of having a socket in the dash, I was thinking of having a longer cable probably routed through the ashtray, but with a male end on it. Would the creation of this cable be any different?
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Re: Build and install your own AUX Cable!

Post by Siftah » Sat Feb 06, 2010 7:50 pm

Kaide wrote:I'm having trouble finding the required parts... I cant find any .6w resistors here... Is there an equivalent in the States?
Hey, they generally come in 1/8th Watt, 1/4 Watt and 1/2 Watt values - 0.6W is ~ 1/2 watt.

The larger of the three are 1/2 watt and will do just fine, they're usually about 3mm wide by 9mm long. You tend to find they're the most common, your local radio shack or similar should have plenty in stock :)
Kaide wrote: Also, I was thinking, instead of having a socket in the dash, I was thinking of having a longer cable probably routed through the ashtray, but with a male end on it. Would the creation of this cable be any different?
There's no reason why that shouldn't* work - I decided to take an existing cable and cut one end off, that way my plug was a nice moulded plug and is likely to stand up to a bit more abuse. There's nothing fundamentally different about making a cable this way, you just have a little less soldering to do as you've only one end of the cable to solder. Pins 3 and 4 will be the right and left channels and those will be white and red coloured in your cable. Red for left, White for right. You'll then have 2 thicker and probably unshielded wires which will be the earth. You'll need to join those together and make sure they go to pin 10, the earth.

* Though, see my next post...

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Re: Build and install your own AUX Cable!

Post by Siftah » Sat Feb 06, 2010 8:17 pm

No joy for me :(

I've tested the cable and it definitely seems to be correct electrically speaking. I've checked each wire with a multimeter and there's continuity across all the cables, 300kΩ resistance between the left and right channel and the pins are all making good contact. I still don't get an AUX-In option on the radio though :(

I ended up buying some of the single pins from Maplins and using those to test, the ones in the photos below were too big to fit into the existing plug so I decided to bypass them and connect straight to the pins on the back of the radio - still no joy :(

For interest and reference, this is what the cable ended up looking like:
Image

Image
Close-up of the way the resistors are soldered into the cable, bridging the left and right channels.

Image
All heat-shrinked and ready to go - fairly neat and tidy and easy enough to hide in the dash without fear of it falling apart. I decided to leave a plug on the end rather than a socket as I wanted to run this through the dash and out the right hand side above the instrument pod. The idea is to use this as a line-in socket from my iPhone TomTom car mount. That would mean I could opt to play music from the iPhone via the TomTom's line-out socket if I wanted to. It'll also let me stream music over the 3G connection, or even play TV shows on the iPhone and have the sound through the HiFi.

Anyway - I've not given up yet, I'll have to do a bit more pondering and have another go at this :\

Things I've left to try:
- Leaving the cable plugged in whilst the car is off and goes into deep sleep, then it'll do a cold boot and maybe it needs a cold boot to recognise a new AUX-IN socket?
- Re-do the cable from scratch, just in case it *is* a dodgy cable and my multimeter isn't showing it up for some reason :\
- Perhaps I should try and use something else with a line-out socket, rather than just testing with the iPhone/TomTom.
- Put the damn capacitors onto the cable, maybe they *are* there for a reason other than filtering after all...

:)

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Re: Build and install your own AUX Cable!

Post by Kaide » Sat Feb 06, 2010 9:19 pm

Siftah wrote: Things I've left to try:
- Leaving the cable plugged in whilst the car is off and goes into deep sleep, then it'll do a cold boot and maybe it needs a cold boot to recognise a new AUX-IN socket?
- Re-do the cable from scratch, just in case it *is* a dodgy cable and my multimeter isn't showing it up for some reason :\
- Perhaps I should try and use something else with a line-out socket, rather than just testing with the iPhone/TomTom.
- Put the damn capacitors onto the cable, maybe they *are* there for a reason other than filtering after all...
Please let me know how this works for you... As soon as you posted that pic of the resistors I was like... "Where are the capacitors?"

If that would work, I'd feel much more comfortable using an existing cable, adding some capacitors, resistors, and ends then starting fresh.
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Re: Build and install your own AUX Cable!

Post by Siftah » Sat Feb 06, 2010 11:44 pm

Kaide wrote: Please let me know how this works for you... As soon as you posted that pic of the resistors I was like... "Where are the capacitors?"

If that would work, I'd feel much more comfortable using an existing cable, adding some capacitors, resistors, and ends then starting fresh.
I'm 100% sure that using a moulded plug rather than a socket will make no difference to the circuit :)

I've come across this page this evening which gives more explanation for why the capacitors are there, this guy mentions uncoupling the audio circuit, which I'm not entirely sure I understand but it at least points to the fact my circuit probably isn't working because of the lack of the capacitors!
http://www.cosninix.com/blog49/index.ph ... 313-010827

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Re: Build and install your own AUX Cable!

Post by Kaide » Sun Feb 07, 2010 12:35 am

These connectors in this photo? do they work as well as the computer connector pins... or do they touch when connected to the radio?
Image
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Re: Build and install your own AUX Cable!

Post by Siftah » Sun Feb 07, 2010 1:56 am

Kaide wrote:These connectors in this photo? do they work as well as the computer connector pins... or do they touch when connected to the radio?
Those were the ones I found were too big, I swapped those for standard header pins (USB header or similar). Even then, they won't fit inside the plastic casing of the original connector so you'll need to replace the existing connector rather than splice the connector into the existing plastic housing.
Last edited by Siftah on Sun Feb 07, 2010 5:11 pm, edited 1 time in total.

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Re: Build and install your own AUX Cable!

Post by VsKoen » Sun Feb 07, 2010 12:21 pm

Just made the cable as instructed capacitors and resistor in place and it works as promised :thumbsup: on Professional radio with bluetooth Tv and Nav. Be sure to have the right capacitors and resistor otherwise it won't work you definitely need them!!
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Re: Build and install your own AUX Cable!

Post by Siftah » Sun Feb 07, 2010 5:18 pm

Siftah wrote: Things I've left to try:
- Re-do the cable from scratch, just in case it *is* a dodgy cable and my multimeter isn't showing it up for some reason :\
Well, I redid the cable from scratch with the capacitors in. Still no dice. I've left it plugged in and the cars off and locked at the moment, so I'll see if I have any luck once it's done a cold boot. Looks like either I've buggered the AUX-IN pins with my earlier messing about or there's something else weird going on :\

Only difference from the spec was that I used polybox capacitors rather than tantalum, as again, that's what I had in my parts box at that capacitance. :\

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Re: Build and install your own AUX Cable!

Post by jhbuining » Sun Feb 07, 2010 5:20 pm

Siftah, the resistor should be on the side of the head unit, so there you should read 300kohm resistance. The side of the head-phone plug shouldn't read that. Did you put the resistor on the right side of the capacitors?
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Re: Build and install your own AUX Cable!

Post by Siftah » Sun Feb 07, 2010 8:06 pm

jhbuining wrote:Siftah, the resistor should be on the side of the head unit, so there you should read 300kohm resistance. The side of the head-phone plug shouldn't read that. Did you put the resistor on the right side of the capacitors?
Seemed to be measuring fine - anyway, I re-made the cable again and it's now working, Woo!

I suspect it was just crappy soldering - I couldn't get the soldering iron to tin properly today, will have to get some cleaning paste for it and sort that out before my next electronics project. I'd probably killed the caps with too much heat or something before, who knows, certainly works now anyway :)

The sound level is a lot lower than the Intravee or the radio, which is a bit frustrating. Plus you can hear a bit of noise too which mostly seems to be from the iPhone itself (would dissapear in Airplane mode no-doubt).

It means I can now play music/video via the iPhone and listen to the sound on the cars speakers anyway, so I'm happy - managed to hide the cabling away behind the dash and pop it out next to the steering column near the iPhone mount so it's a reasonably tidy install.

I think my next job will be to take the cigarette lighter socket plug for the TomTom/iPhone and hardwire that into a power feed behind the dash which is only live with the ignition. I hate having the plug in the cigarette lighter socket all the time, looks so untidy. After todays ham-fisted attempts at soldering that can wait until next weekend :)

The single pins from Maplin are well worth buying, whether you've got the bluetooth audio plug installed or not. With the pins you can leave the existing plug as-is and use the Maplin connectors to extend it and then glue together the new connectors to make a replacement. Glueing them together will make them easier to plug in I think (I haven't done this myself yet).

Cheers all - will post some pics later :)

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Re: Build and install your own AUX Cable!

Post by Kaide » Mon Feb 08, 2010 12:42 am

Siftah wrote:I think my next job will be to take the cigarette lighter socket plug for the TomTom/iPhone and hardwire that into a power feed behind the dash which is only live with the ignition. I hate having the plug in the cigarette lighter socket all the time, looks so untidy. After todays ham-fisted attempts at soldering that can wait until next weekend :)
FYI, I can guarantee that the 12v to the cigarette lighter is hot 24/7, ignition on or off. Just keep that in mind before you start splicing.
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