06 Nov 2018 17:54 - 06 Nov 2018 17:58#40782by Algernon
For Scott's benefit, here's a little thread about my ongoing quest to get a perfect in-car computer solution working in my motor.
The car in question is my new (to me) Saab 9-3 Aero Cerulean Convertible, which replaced my old, much-loved but rather worn 9-3 Vector Convertible. Stage 1 of the project, detailed below, was prototyped on the old car and is in the process of being installed in a modified configuration based on that initial prototype, with improvements (hopefully).
Basically, Stage 1 is installing power circuits for the eventual carputer, which will be Android based and operated by a touchscreen installed in front of the gear selector, where there is currently a handy storage area. The plan is to 3D print a custom fascia with Alex's help to make it look like original equipment. However, that's in the future - for now, just the power is going in. I've already installed one spur from an ignition source (ignition key on or engine running) and I'm installing another which is always on.
These are currently powering a cute wireless charging cradle with motorised arms which move in to grip the phone when placed in the cradle, and a bluetooth audio/controller unit patched into the car's AUX audio input.
This is, unfortunately, a rather crude arrangement - the ideal situation would be that the spur currently activated by the ignition (ON setting on the key assembly) would actually be powered when the key was turned to the first (OFF) position, but it seems it's not immediately possible just taking power from a fuse tap out of the fusebox.
I have a potential solution using a little custom circuit - Scott, maybe your experience with electronics might assist me to come up with something here...
06 Nov 2018 18:41 - 06 Nov 2018 19:38#40786by ScottBouch
Nice looking motor!
I recall looking round an older SAAB a few years ago and being surprised at how similar it was to a V6 Cavalier / Vectra under the bonnet... lots of shared components and chassis members.
What's the end goal of your computer? Media player?
You definately need a permanent power supply for a computer to be able to shut it down upon turning off the ignition. If you can't find a permanent supply on the back of the dashboard fuse box, you may have a fuse box in the engine bay where you could pick up a permanent supply and run a wire though the bulkhead (not as hard work as it sounds). Shutting it down is important as you could end up with a flat battery if left on accidentally, further to this all electronics draw sone quiescent current when 'off' - make sure thos is minimal to avoid draining the battery. Other power solutions include a small leisure battery and split charger - then you can use the computer till the leisure battery is dead, and it won't have affected your main car battery.
Here is my recent project along these lines:
The car (Seat Altea XL Freetrack) had a screen already, but just down to three phono sockets in an awkward location, where you needed to bring along some portable player of sorts....
I wanted to integrate the player hardware into the car, so used a £4.00 Raspberry Pi Zero, A £10 HifiBerry DAC audio board, a USB phone charger a client gave to me, and other bits I had in the garage.
I didn't have a permanent power line in this area, so had to bodge it by using a USB charger battery to give it power after the car switched ignition power had been removed. I used a GPIO pin to observe the power going off, and run a script to shut it down on the USB charger battery power.
06 Nov 2018 21:26 - 06 Nov 2018 21:44#40792by ScottBouch
Have you ever tried using an Android touchscreen stereo in a car whilst moving?
We have an EONON Android head unit. I can only describe it as clunky, not user friendly, and fiddly.
I use VLC to play music & audiobooks from a micro SD card. I use OSMand for sat nav with offline maps saved to the device. Neither of these applications are skinned for touching while driving. They have fiddly menus and settings.
I prefer tactile controls on a car radio as by the feel of it you can change radio stations without taking your eyes off the road. Touchscreens require a lot of 'looking at' to get your fingers over the right pixels. But when apps have small fiddly menus, this issue is amplified, then add in bumpy roads and it's far from ideal.
The processor in this head unit is very weedy too, so it takes forever to calculate journeys, load maps, etc...
It also annoyed me that I had to have a Google Play Store account and hook it up to my home wifi in order to install the two apps I mentioned. I made up a random email account for this purpose as I hate Google tracking me, I don't want my car tracked too. The reason I'm using Open Street Maps and VLC is to avoid tracking.
All in all, its a bag of 5hite.
I'd like to design my own from the ground up, but that's another big project! In an ideal world it'd be Linux based, have feel recognisable buttons of various shapes and sizes for the functions i'd need while driving, only needing to use the touchscreen for setting a sat nav detonation before the journey. I'd keep the features basic and no-frills, ie; what do I actually need for a journey... certainly not the Gmail app!
Well, there's no reason why I couldn't have a Raspberry Pi instead - in fact, it would be an awful lot easier. Part of the project is to have the computer communicating with the car itself via the bus, so at the very least, most functions can be accommodated by steering wheel buttons.
Delightfully, the Saab steering wheel has a "speech" button which doesn't do anything, but is detectable on the bus, so I will be able to trigger Google's voice search function for most things that I can't use the steering wheel buttons for. Touchscreen will be the third, least desirable interface.
I hear what you say about Google - I'm beginning to properly hate them - but I'm afraid as far as navigation is concerned, they can't be beat. Google Maps is waaaaay better than the next nearest competitor for driving navigation. So I have accepted the demon into my car. However, if they continue to get scarier, it's entirely possible I'll have a change of heart.
Referring to your earlier comments about the Saab - yes, from about 2003 on Saab was acquired by General Motors and the 9-3 was resdesigned to utilise the GM Epsilon platform which was shared with, among a number of others, the Vauxhall Vectra. Unkind people whose only motoring knowledge is gleaned from quoting Jeremy Clarkson and those two other twats will allege the 9-3 is just a tarted-up Vectra, whilst throwing in various other barbs about Saab's financial sustainability. Well, I've owed a Vectra - quite a nice one - and it's not a patch on the Saab, especially my newer one which is the sportier Aero spec, with a big fat turbo (210bhp at present) and sports brakes and suspension.
I'll let you know about the power question when I get back from this latest trip, I will hopefully have a bit more of an idea about what's possible after the latest disassembly!
Hi, I had the Vectra predecessor, a mid 90's Cavalier for a while (just needed a cheap car). It's crappy "Ecotec" engine died, so I installed a C20XE engine from an Astra GTE... I still handled like a boat, but didn't half shift!
Long gone are my hot hatch days... had a few Mk2 Astra GTE's, and would have another tomorrow! But family wagons win now..
Yeah, there was a time when I was at college that I thought the fast Vauxhalls were rather tasty - I liked the Nova and Astra GSi - but shortly afterwards, I cancelled my Max Power subscription and went all classic convertible: Triumph Spitfire Mk2 and Alfa Spyder 2000 Veloce were two of my fun but less than perfect purchases. I found they worked better with the type of girl I was interested in - growing up in Essex, one had to be cautious!!