Little sat nav build for my Lexus
31-01-2015, 02:57 PM
#1
Little sat nav build for my Lexus
Yes I know it's not a Ford, but I thought I'd share anyway as I so rarely do anything with cars these days (in terms of modifying I mean) 
Decided to follow up on this sat nav build, since I never got round to it. I bought the 7" housing a couple years ago, and bought a cheap Chinese GPS off eBay, then when it got here, realised it didn't have an AV input (for reverse cam that I also want to install), and when I tried to send it back under their "no quibble 14 day UK distance selling regulation" return policy, they would only accept returns to China, even though they were advertising as a UK seller! Complained to eBay and got full refund, inc postage, and was able to keep the GPS! So they've both sat here for a couple years doing nothing, until I decided I should really give it a go, hopefully with help on the wiring (my achilles heel) from a work mate, after I put in the physical build work.
So, the other night I ripped it apart;
Did a quick. slot in, test fit with the tablet;
And then set about ripping the tablet apart - the connectivity is all on the side of the unit, and there isn't room inside the housing to plug anything in. I'd have to rip it apart to get to the PCB anyway, and I wanted to relocate it if possible, thus avoiding having to solder directly onto it for power etc
With the PCB loose, I can easily plug a USB cable in for power without having to solder directly onto the PCB, thus making the USB port still operational if I need to plug it into a computer for updates etc.
Then, I broke a wire off the PCB! Turns out to be the wire that lets the battery charge, so I can still boot up at the mo, but not charge. Not the end of the world because it will have constant power once in the car and wired in
Anyway, with a couple holes drilled in the back casing to cable tie the PCB down, I glued a couple of crude wooden blocks to the sides of the housing. Reason for this is it holds the tablet perfectly snug and tight, but allows me to pull the tablet out if need be - more on that later;
The reason for being able to slide it out is 1) in case I need to plug it into my computer for anything, and also 2) this is just the test bed. Because this GPS owes me nothing, I'm happy to experiment with it (I've also compromised the screen ribbon cable, so it's a bit iffy displaying an image), but if we can get this all working how I'd like (which is to try to replace the GPS on/off switch with a trigger, so that it powers on with ignition and off again with power cut) then I'll buy a newer one, this time with the AV input for reverse camera, and possibly also with bluetooth so I can (hopefully) connect my phone to it for handsfree (the idea is I can plug the 3.5mm jack from my Grom into the tablet, and possibly solder a separate mic onto it, rather than use the internal mic, which of course will be inside the housing.
Also, I spotted this microSD to SD card extender on ebay which would be good to connect to the microSD card slot on the PCB, run it behind the head unit and under the console and maybe have it come out in the ashtray? That way I can load stuff onto a regular size SD card and hot swap it on the move, rather than having no access to the mSD slot without removing the entire tablet.
Wiring is my problem - I can't solder and I'm useless with electronics! But hopefully a work colleague is gonna help me try and get it all working. Plan is to wire the power for the housing to a computer molex connector, and then tap into the cars wiring for that power, to another molex - making it completely removable, rather than hardwired (should I want to sell it or move it to another car later on). As for power for the tablet, the plan is to simply use the USB to cigarette power adapter, but wire a female cig socket (probably into the wiring for the existing cig lighter) and just mount it behind the dash and plug directly into it - again making it simple to unplug if need be.
And hopefully, with the newer tablet, I might be able to get this logo to be the default splash screen during boot (can't get it to work on the current one)
Decided to follow up on this sat nav build, since I never got round to it. I bought the 7" housing a couple years ago, and bought a cheap Chinese GPS off eBay, then when it got here, realised it didn't have an AV input (for reverse cam that I also want to install), and when I tried to send it back under their "no quibble 14 day UK distance selling regulation" return policy, they would only accept returns to China, even though they were advertising as a UK seller! Complained to eBay and got full refund, inc postage, and was able to keep the GPS! So they've both sat here for a couple years doing nothing, until I decided I should really give it a go, hopefully with help on the wiring (my achilles heel) from a work mate, after I put in the physical build work.
So, the other night I ripped it apart;
Did a quick. slot in, test fit with the tablet;
And then set about ripping the tablet apart - the connectivity is all on the side of the unit, and there isn't room inside the housing to plug anything in. I'd have to rip it apart to get to the PCB anyway, and I wanted to relocate it if possible, thus avoiding having to solder directly onto it for power etc
With the PCB loose, I can easily plug a USB cable in for power without having to solder directly onto the PCB, thus making the USB port still operational if I need to plug it into a computer for updates etc.
Then, I broke a wire off the PCB! Turns out to be the wire that lets the battery charge, so I can still boot up at the mo, but not charge. Not the end of the world because it will have constant power once in the car and wired in
Anyway, with a couple holes drilled in the back casing to cable tie the PCB down, I glued a couple of crude wooden blocks to the sides of the housing. Reason for this is it holds the tablet perfectly snug and tight, but allows me to pull the tablet out if need be - more on that later;
The reason for being able to slide it out is 1) in case I need to plug it into my computer for anything, and also 2) this is just the test bed. Because this GPS owes me nothing, I'm happy to experiment with it (I've also compromised the screen ribbon cable, so it's a bit iffy displaying an image), but if we can get this all working how I'd like (which is to try to replace the GPS on/off switch with a trigger, so that it powers on with ignition and off again with power cut) then I'll buy a newer one, this time with the AV input for reverse camera, and possibly also with bluetooth so I can (hopefully) connect my phone to it for handsfree (the idea is I can plug the 3.5mm jack from my Grom into the tablet, and possibly solder a separate mic onto it, rather than use the internal mic, which of course will be inside the housing.
Also, I spotted this microSD to SD card extender on ebay which would be good to connect to the microSD card slot on the PCB, run it behind the head unit and under the console and maybe have it come out in the ashtray? That way I can load stuff onto a regular size SD card and hot swap it on the move, rather than having no access to the mSD slot without removing the entire tablet.
Wiring is my problem - I can't solder and I'm useless with electronics! But hopefully a work colleague is gonna help me try and get it all working. Plan is to wire the power for the housing to a computer molex connector, and then tap into the cars wiring for that power, to another molex - making it completely removable, rather than hardwired (should I want to sell it or move it to another car later on). As for power for the tablet, the plan is to simply use the USB to cigarette power adapter, but wire a female cig socket (probably into the wiring for the existing cig lighter) and just mount it behind the dash and plug directly into it - again making it simple to unplug if need be.
And hopefully, with the newer tablet, I might be able to get this logo to be the default splash screen during boot (can't get it to work on the current one)
Last edited by Thrush; 31-01-2015 at 03:01 PM.
01-02-2015, 11:11 AM
#7
I haven't even tested the motorised function of this housing yet, so it might not even work
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02-02-2015, 05:22 PM
#8
It's on hold now cos I've broken it One of the wires going to the power button on the screen broke off, so now I can't turn it on So I need to buy a soldering iron and stuff, and brush up my (non existent) skills, and see if I can fix it (probably completely destroy it)
One of the wires going to the power button on the screen broke off, so now I can't turn it on So I need to buy a soldering iron and stuff, and brush up my (non existent) skills, and see if I can fix it (probably completely destroy it)
04-02-2015, 10:31 PM
#11
Still waiting on my mate to help me (try and) fix the PCB on the GPS, but a little temporary wiring hooked up to a car battery (crude, but effective 
) let me test the pins on the housing, and check the motor and lights work on it - which they do!
) let me test the pins on the housing, and check the motor and lights work on it - which they do!
05-02-2015, 08:59 AM
#12
looks a nice install.
If you use a reletively new android tablet, you can run an app called 'tasker' which when the external power supply is lost, will automatically put the tablet into aeroplane mode, turn screen off etc.
Then when power is resumed it can enable GPS and data, and start any apps you want.
Makes for nice quick startup times.
Have a read of this
http://www.rx7club.com/adaptronic-en...-more-1037541/
You won't need the ecu interface bit, but the audio output is pretty good.
If you use a reletively new android tablet, you can run an app called 'tasker' which when the external power supply is lost, will automatically put the tablet into aeroplane mode, turn screen off etc.
Then when power is resumed it can enable GPS and data, and start any apps you want.
Makes for nice quick startup times.
Have a read of this
http://www.rx7club.com/adaptronic-en...-more-1037541/
You won't need the ecu interface bit, but the audio output is pretty good.
05-02-2015, 03:54 PM
#13
Audio I've got taken care of with a little box of tricks that interfaces my standard HU with my iPod, so this screen will really only be used for GPS and reverse cam, and possibly bluetooth for my phone, if it's any good.
I did look at Android tablets but the two problems I've got is;
1) finding one that has an AV input (for the reverse cam), and it needs to autoswitch the AV channel both on and off with power/video signal
2) Getting one that isn't too big, and doesn't need any external buttons. The screen size on the housing is exactly 7", and finding a 7" screen Android tab isn't exactly hard, but finding one that the has a small enough screen surround is the tricky part, as if it's too big it won't physically fit inside the housing (the one I've got is pretty slim, and even that only has at most a couple mm top and bottom play, and probably 2.5-3mm side to side play. Almost a perfect fit!). And if it needs external button presses, like a home button or whatever, I won't be able to press them, as the cut out is only 7", and I really don't want to spoil the looks by cutting out a notch to press a button.
Data would be cool on it, as then I could run Google maps and tether it to my iPhone for internet, but at the same time, half the reason for going to way I've gone is to get a full "offline" map package, so that if I'm in an area with no cell data, the sat nav will still work (whereas Google maps, and Apple maps for that matter, just goes blank because it's constantly "streaming" it's maps over cell data. (Plus, I could run the TV Catchup app, and get BBC News 24 going on ; ) )
But there's always the future - this is really just a test to see if it can be done and all work fine, then I'll get another GPS tablet an start again, along with plumbing in a reverse camera and Bluetooth - then later I can see what's about and whether that can be incorporated
I did look at Android tablets but the two problems I've got is;
1) finding one that has an AV input (for the reverse cam), and it needs to autoswitch the AV channel both on and off with power/video signal
2) Getting one that isn't too big, and doesn't need any external buttons. The screen size on the housing is exactly 7", and finding a 7" screen Android tab isn't exactly hard, but finding one that the has a small enough screen surround is the tricky part, as if it's too big it won't physically fit inside the housing (the one I've got is pretty slim, and even that only has at most a couple mm top and bottom play, and probably 2.5-3mm side to side play. Almost a perfect fit!). And if it needs external button presses, like a home button or whatever, I won't be able to press them, as the cut out is only 7", and I really don't want to spoil the looks by cutting out a notch to press a button.
Data would be cool on it, as then I could run Google maps and tether it to my iPhone for internet, but at the same time, half the reason for going to way I've gone is to get a full "offline" map package, so that if I'm in an area with no cell data, the sat nav will still work (whereas Google maps, and Apple maps for that matter, just goes blank because it's constantly "streaming" it's maps over cell data. (Plus, I could run the TV Catchup app, and get BBC News 24 going on ; ) )
But there's always the future - this is really just a test to see if it can be done and all work fine, then I'll get another GPS tablet an start again, along with plumbing in a reverse camera and Bluetooth - then later I can see what's about and whether that can be incorporated
10-02-2015, 09:21 PM
#14
Still not further on, as I still need to hook up with my mate to do some soldering and try to find a work around for the on/off switch in the GPS tablet. I've discovered that if I bridge the points where the press switch used to be, the tablet will power up. However, if the points remain bridge, it will turn itself off again after a few seconds - and it can only be rebooted by removing the bridge, and rebridging it. So, I need to find a work around that will allows these two points to remain physically bridged, but only allow a power flow through them fir the first few seconds, then after that either divert the power flow somewhere else or interrupt it. Something like a pulse power circuit, or in layman terms (and I'm a fucking layman when it comes to this ) a "gate"
On a brighter note, I got hold of the original plug that fits this nav housing, only to find after receiving it, the pin connections aren't quite as they should be. Seems it's from an earlier model, and although the plastic plug is the same, it's missing some connections for the pins I need to use. So I reverted to the original plan of cutting up a computer molex connecter - one end of which will have female spade crimps on the wires, which will attach to the pins on the nav housing, and the other end of which will be hard wired into the stereo wiring. Turns out, that's easier said than done, as the smallest crimps are just that teensy bit too big; they can be made to fit, but they touch. I could insulate them with heat shrink, but I'm still not 100% convinced.
So I looked out a brand new ISO harness I've had in a drawer for years and years and never used (think it's ISO to mk4 Escort plugs) and hacked that about until I got two of the female pin receivers out, with their wires. Not a direct fit into the Lexus nav plug, but a bit of bending and squashing with some pliers and I got them in, and with a bit of careful angling, the plug fits in the nav, and all connections are made - tested it hooked up to a car battery and (same as the video above) and all functions work. So that's pretty cool, as all I'll need to do now is put a half metre or so of wiring on each of the 5 wires, insulate and wrap them, then they can be spliced directly into the stereo wiring for power, ground, and illumination
Ordered me some heat shrink and a "my first soldering set" off eBay, so when that arrives I'll have a go at extending the wires, fit the two-pin plug to the GPS power wires (so that that can be plugged and unplugged at the dash-top end too) and hopefully won't be long after that, that we can start on trying to hack the power button on the GPS tablet
) a "gate" On a brighter note, I got hold of the original plug that fits this nav housing, only to find after receiving it, the pin connections aren't quite as they should be. Seems it's from an earlier model, and although the plastic plug is the same, it's missing some connections for the pins I need to use. So I reverted to the original plan of cutting up a computer molex connecter - one end of which will have female spade crimps on the wires, which will attach to the pins on the nav housing, and the other end of which will be hard wired into the stereo wiring. Turns out, that's easier said than done, as the smallest crimps are just that teensy bit too big; they can be made to fit, but they touch. I could insulate them with heat shrink, but I'm still not 100% convinced.
So I looked out a brand new ISO harness I've had in a drawer for years and years and never used (think it's ISO to mk4 Escort plugs) and hacked that about until I got two of the female pin receivers out, with their wires. Not a direct fit into the Lexus nav plug, but a bit of bending and squashing with some pliers and I got them in, and with a bit of careful angling, the plug fits in the nav, and all connections are made - tested it hooked up to a car battery and (same as the video above) and all functions work. So that's pretty cool, as all I'll need to do now is put a half metre or so of wiring on each of the 5 wires, insulate and wrap them, then they can be spliced directly into the stereo wiring for power, ground, and illumination
Ordered me some heat shrink and a "my first soldering set"
off eBay, so when that arrives I'll have a go at extending the wires, fit the two-pin plug to the GPS power wires (so that that can be plugged and unplugged at the dash-top end too) and hopefully won't be long after that, that we can start on trying to hack the power button on the GPS tablet
10-02-2015, 09:48 PM
#15
PassionFord Post Whore!!
Good work mate ,I wouldn't even know where to start , I cant even work out how to use my I pod in the RS4, I need to update the software or a lead or some thing
10-02-2015, 11:01 PM
#16
Possibly thinking a bit too far ahead, seeing as I haven't even got this running yet, but I just had a thought about maybe installing a dash cam inside this unit too - there might be enough room inside the housing to fit a compact dash cam (if I can find a nice slim one without a projected lens), and cut a hole in the casing so that when the screen is up, the top of the casing becomes the back, facing the road. No idea if there's a clear line of sight over the dash, just an idea at the mo
16-03-2015, 09:30 PM
#17
Right, been a bit quiet on this front for a while, but got it all in and working today, thanks to the help of my work friend who very kindly sacrificed his afternoon (and evening!) to sit outside in a cold car park soldering it all in for me (because I really suck at soldering!)
Anyway, not a lot to look at and no pics of the finished article because it got dark by the time we finished it, so I'll throw some up on tomorrow or Wednesday, but we started by soldering on the wires from the units plug to some wiring I bought in, and sheathed it up with a loom sleeve to make it look as OEM as possible;
I tried to match the colours as best as poss, although they ended up being hidden from the top end as we pulled the sleeve up and taped it up. But at least it made it easier at the bottom end for wire ID'ing.
So next we moved into the car, and started the bit I was dreading - cutting into the nice, virgin, loom for the stereo plug! Cut and spliced that with the wiring for the nav housing loom, and tried to make it as neat as poss with heat shrink and the original loom sleeving neatly cut and taped back in place. I really hate messy wiring, which is ironic as I'm totally crap at wiring, but there you go.
So with that done, we tapped into the positive (switched live) that goes to the dash cig socket, and spliced in the positive wire for a female 12v socket (the negative we just crimped a ring terminal to and grounded it on a chassis bolt, as there really wasn't much wiring down there to play with) and ran that behind the dash to provide power for the USB plug that powers the actual tablet. Then we repaired the broken off wires from the tablets PCB and extended the two wires that form the power switch for the tablet. Initially I wanted the tablet to automatically power on with ignition, and then power off with ignition cut, and after testing we found the power switch wiring has one wire thats a constant 3.7v live, and the other wire is nothing - so that when you press the power button, and hold for a few seconds, the circuit is completed and the tablet powers on. Press and hold again and it powers off. Just as we thought. However, we couldn't see an easy way to get it to complete the circuit, or feed it a few seconds worth of 3.7v on ignition on/off, in order to power it on/off. We looked at using the motor - when the unit opens the motors runs for about 2-3 seconds to open, and another 2-3 seconds to close, which should be enough time to supply power to turn it on and off, but testing the motor we found a) the motor was kicking out 9-10 volts and b) the red and black wire on it isn't actually positive and negative - it's forward and reverse! So the power side of it must be controlled at the PCB end of the housing. We decided it was too much grief to try stepping down the voltage from the motor to 3.7v for the power button, and also the power button works as a home button (like an iPhone) when you press and release quickly - so by wiring to the motor, using the tilt function would keep kicking you out the sat nav app back to the home screen.
So, in the end we decided to extend the wires from the power button down behind the dash to a teeny tiny press button, fitted out of site under the console - where I can easily reach it, but it can't be seen or knocked. Not ideal, as it means I manually have to turn it on and off, but at least all functionality is retained. No pics of that as it was dark by the time we got this all in.
So it's all in and working, functionality of the nav housing remains the same, and the functionality of the tablet itself remains the same - except the for the speaker which I left off, since I won't need it (I never use the spoken directions on sat navs).
Next steps are to try and hack TomTom Navigator to run on this, and then change the tablet itself to one with an AV input and plumb in a reverse camera.
Pics to follow when I can take some in daylight
Anyway, not a lot to look at and no pics of the finished article because it got dark by the time we finished it, so I'll throw some up on tomorrow or Wednesday, but we started by soldering on the wires from the units plug to some wiring I bought in, and sheathed it up with a loom sleeve to make it look as OEM as possible;
I tried to match the colours as best as poss, although they ended up being hidden from the top end as we pulled the sleeve up and taped it up. But at least it made it easier at the bottom end for wire ID'ing.
So next we moved into the car, and started the bit I was dreading - cutting into the nice, virgin, loom for the stereo plug! Cut and spliced that with the wiring for the nav housing loom, and tried to make it as neat as poss with heat shrink and the original loom sleeving neatly cut and taped back in place. I really hate messy wiring, which is ironic as I'm totally crap at wiring, but there you go.
So with that done, we tapped into the positive (switched live) that goes to the dash cig socket, and spliced in the positive wire for a female 12v socket (the negative we just crimped a ring terminal to and grounded it on a chassis bolt, as there really wasn't much wiring down there to play with) and ran that behind the dash to provide power for the USB plug that powers the actual tablet. Then we repaired the broken off wires from the tablets PCB and extended the two wires that form the power switch for the tablet. Initially I wanted the tablet to automatically power on with ignition, and then power off with ignition cut, and after testing we found the power switch wiring has one wire thats a constant 3.7v live, and the other wire is nothing - so that when you press the power button, and hold for a few seconds, the circuit is completed and the tablet powers on. Press and hold again and it powers off. Just as we thought. However, we couldn't see an easy way to get it to complete the circuit, or feed it a few seconds worth of 3.7v on ignition on/off, in order to power it on/off. We looked at using the motor - when the unit opens the motors runs for about 2-3 seconds to open, and another 2-3 seconds to close, which should be enough time to supply power to turn it on and off, but testing the motor we found a) the motor was kicking out 9-10 volts and b) the red and black wire on it isn't actually positive and negative - it's forward and reverse! So the power side of it must be controlled at the PCB end of the housing. We decided it was too much grief to try stepping down the voltage from the motor to 3.7v for the power button, and also the power button works as a home button (like an iPhone) when you press and release quickly - so by wiring to the motor, using the tilt function would keep kicking you out the sat nav app back to the home screen.
So, in the end we decided to extend the wires from the power button down behind the dash to a teeny tiny press button, fitted out of site under the console - where I can easily reach it, but it can't be seen or knocked. Not ideal, as it means I manually have to turn it on and off, but at least all functionality is retained. No pics of that as it was dark by the time we got this all in.
So it's all in and working, functionality of the nav housing remains the same, and the functionality of the tablet itself remains the same - except the for the speaker which I left off, since I won't need it (I never use the spoken directions on sat navs).
Next steps are to try and hack TomTom Navigator to run on this, and then change the tablet itself to one with an AV input and plumb in a reverse camera.
Pics to follow when I can take some in daylight
The following users liked this post:
Thrush (17-03-2015)
The following users liked this post:
Thrush (17-03-2015)
19-03-2015, 06:31 PM
#21
Thanks guys. It's not the best sat nav in the world (however it's still better than the stock option for reasons mentioned above), but the main brief was get it as OEM looking as poss. I'd love to throw in a more modern Android tablet, which would be even better if I could tether it to my iPhone so it was "smart", but it's finding one with the right dimensions, screen in the right place, and has an AV input for a reverse camera. Tall order...
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