Squig
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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 3:39 pm

I have spend this afternoon reading your boards, after popping my request into RS components, and thought I'd join the forum and chat though the idea that I've been toying with for some months.

Out of the box it's about running a car pc... unoriginal and boring. Sorry about that, and it's possible I'll be skirting the edge of the good old Android on Rasberry Pi debate/discussion/arguement. Again, sorry...

However with those apologies hanging over this post already I'll get on and explain;

I wanted to build a car pc out of old PC components I've acquired over the years, and, to cut out a long and dull history, built a little media center running an old Sempron CPU with 2Gb ram all running at 300Mhz FSB. Basic, slow and not brilliant, but perfect to get something like a test bed for various OS distros (mainly Linux variants) as it cost me nothing.

Now having tried almost every media center type software I can find available that keeps me at my £0.00 budget I am forced to admit there is only one or two linux based programs I feel the GUI would be easy enough to navigate while driving (by this I mean; easy access to play, skip track and volume functions without my eyes leaving the road), and that's not to mention the problematic sat-nav idea.

Hence the thought of an older Android distro, but there are plenty of threads concerning that topic and I'm not massively keen on cloning it here, unless it must, so that's enough there.

The other consideration, quite apart from size, is power consumption and Rasberry Pi's tiny ampage would mean it could be left for 2-3 days in standby, and thats without fitting a photovoltaic trickle charger.

My queries start with the GPIO and it's suitability to switch the Rasberry Pi from a standby state into an on state with a continuous positive feed and return to standby when said feed is switched off. Can anyone shed some light on this?

Any thoughts on this would be welcome (as would any suggestions of alternative software, be it OS or application), am I barking up the wrong tree looking to Rasberry Pi, or do I start saving?

PS. it's worth a quick note that I am not strictly on a £0 budget I just didn't want to start spending before I had looked at the software side of things, and I am not a programmer of any calibre. I can cobble things together and follow instruction but I know virtually nothing of building my own linux OS nor app creation, and know no-one who could show me or help, so please don't tell me to build a custom front-end or my own GUI for a pre-existing sat-nav program... If I could have I really, really would have!

Thanks for reading,

Dan

SirLagz
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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 3:43 pm

With the RasPi, if power is plugged in, it's on.

Otherwise, It's off.

So unless you rig up a power daughter-board connected via GPIO to do the switching, you're not going to get very far.
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Squig
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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 3:58 pm

Maybe I should have mentioned I'm not terribly electronically minded as well… however my brother is an electronics engineer, so with that I can get help.

However let me ask this possibly pointless question; assume I'm more than a little experienced with the vehicle (it's always in bits ) I'd say I can find a permanent feed and hook up a board to deliver a continuous 5v feed to the RasPi (surge protected; courtesy of the aforementioned brother), and a separate board that can give an on or off feed dependant on ignition status, I was purely wondering about standby…

I wouldn't want to see a full boot sequence each time the car is switched on, that is the crux of the question.

SirLagz
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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 4:10 pm

I don't think there really is a 'standby' function in the Raspberry Pi...

I may be wrong as I don't actually have one, but I was under the impression that standby is a function of the BIOS, which the Raspberry Pi does not have.

The boot sequence on the Raspberry Pi is already fairly fast, within seconds from anecdotal evidence.
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Squig
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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 4:14 pm

Ahh... I see, that would indeed be less of an issue then. Thanks for the prompt reply.

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Re: Rasberry Pi as in car pc

Sun Apr 15, 2012 7:54 pm

Squig said:


Maybe I should have mentioned I"m not terribly electronically minded as well… however my brother is an electronics engineer, so with that I can get help.

However let me ask this possibly pointless question; assume I"m more than a little experienced with the vehicle (it"s always in bits ) I"d say I can find a permanent feed and hook up a board to deliver a continuous 5v feed to the RasPi (surge protected; courtesy of the aforementioned brother), and a separate board that can give an on or off feed dependant on ignition status, I was purely wondering about standby…

I wouldn"t want to see a full boot sequence each time the car is switched on, that is the crux of the question.


I'm assuming your using all the cables available in the back of your radio? You would most likely just need to hook it up to the on/off ignition power and ignore the constant power. Then ignition on - RasPi on. Otherwise the the unit will be on the entire time. Although I'm not sure whether that would be a problem, most of the thread's I've read around here say the unit doesn't get hotter than 45 Celcius as long as there's some passive airflow.

If you're trying to figure our a feed, why don't you run it off the 5v cigarette lighter? I'm 99% sure the output is 5V 1000mA, or at least you can buy converters on flea-bay for ~ £1. Then when you want to power it on, you just plug it in.
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Squig
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Re: Rasberry Pi as in car pc

Mon Apr 16, 2012 12:58 am

my brother suggested a power converter hooked into the ignition live... tbh I'd ideally want it to be installed hidden away (possibly in the center air vents which aways blow cold; any cooling issues solved right there)

SirLagz
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Re: Rasberry Pi as in car pc

Mon Apr 16, 2012 1:47 am

Cigarette lighters are 12V 10A.

Cheap 12V -> 5V converters can be had for a few dollars though.

As long as the RasPi won't be writing anything to the SD card when you turn the car off, that will work. Just hook up the adapter to the IGN or ACC wire.
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crashingdutchman
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Re: Rasberry Pi as in car pc

Wed Apr 18, 2012 9:50 am

I would like to extend the idea of T/S a bit with the possibility to control the Rpi over a bluetooth and/or wireless connection with my mobile phone. This way an extra monitor is not needed.

If this is possible, then I can hide the Rpi somewhere in the back of the car. Connect audio cable in between RPi and my car stereo that has aux-in. It might even be possible to stream GPS data from my phone to RPi for navigation purposes.

Any ideas if this would be feasible?

hzrnbgy
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Re: Rasberry Pi as in car pc

Wed Apr 18, 2012 12:47 pm

I had some prototype boards built that comes with a bluetooth and GPS headers so I can do exactly what you're thinking, controlling the Pi from a bluetooth device, not necessarily from a mobile phone but could be anything from a custom dashboard or tablet, etc.

I already got the board all good to go but I don't have an RPi yet so my development is stalled for the time being.

I'm currently working on a custom camera board that hopefully could integrate with the RPi for back-up monitoring.

crashingdutchman
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Re: Rasberry Pi as in car pc

Wed Apr 18, 2012 12:50 pm

I got my RPi. If there is anything I can test for you, just let me know!

hzrnbgy
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Re: Rasberry Pi as in car pc

Wed Apr 18, 2012 1:04 pm

The plan is the RPi talk to the custom board via a serial. In header connection in the board below, the xmega controller can talk to the RPi via serial, I2C, or SPI but since there are no SPI or I2C driver yet, I programmed the controller to listen on the serial port for commands coming from the RPi

All commands from the RPi will be packetized in some way that the built in controller in my board can decode. This is for communication from RPi to board. I can easily test this as I have a few serial cables that can emulate serial connection.

I'm not quite sure how I am going to implement communication from board to RPi. You can always do a loop in a Linux program looking for received characters in the serial buffer but that's not very efficient and slow. That's where I'm having problem with as I don't have an actual system to test on. I'm not quite sure either if you can implement interrupt is a user space program in Linux because that's how I would do it.

smnanthny
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Re: Rasberry Pi as in car pc

Wed Apr 18, 2012 2:35 pm

This is an interesting topic. I'm looking at using the RPi as some kind of in-car entertainment hub - as simple as possible because I don't have your knowledge.

Shall keep my eye on this thread.

toony
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Re: Rasberry Pi as in car pc

Wed Apr 25, 2012 5:27 pm

Very interesting topic indeed.

I had the same idea some time ago. Only that the RPi is hidden behind the dashboard. With a fm-stick for the radio and a wifi-stick to connect a smartphone or tablet to it. I was thinking of a small web-interface or even a fancy iOS native-app to control the RPi. And running an airplay-client (audio only) on the RPi would make it a media center.

This would make a nice car pc at nearly no costs.

thickycat
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Re: Rasberry Pi as in car pc

Sun May 06, 2012 10:51 pm

I was also thinking how neat an incar PC the RasPi would make. Could the unit be powered from the permanent live but using the ignition feed (or lack of it) on an I/o port to trigger a polite shutdown, perhaps using some UPS functionality in the OS?

I appreciate these feeds would need dropping to 5v...

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Re: Rasberry Pi as in car pc

Sun May 06, 2012 10:59 pm

SirLagz said:


I don't think there really is a 'standby' function in the Raspberry Pi...

I may be wrong as I don't actually have one, but I was under the impression that standby is a function of the BIOS, which the Raspberry Pi does not have.

The boot sequence on the Raspberry Pi is already fairly fast, within seconds from anecdotal evidence.


Not really a "standby function", but the GPU goes automatically in low power mode when it is not used, which means that power usage is strongly reduced when not writing to the video system.

rmcgeown
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Re: Rasberry Pi as in car pc

Wed May 16, 2012 2:33 pm

Not really a "standby function", but the GPU goes automatically in low power mode when it is not used, which means that power usage is strongly reduced when not writing to the video system.
It could be used as a secondary alarm system in low power mode?

Nightwing2012
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Re: Rasberry Pi as in car pc

Thu May 17, 2012 4:09 pm

Been thinking of this for a short time.

On most car radio stereo hook up. There is an always powered 12 V line and a switch 12 V line or some control saying turn on. Maybe a low level module using a low power chip like a Propeller, PIC what ever that handles start up and shut down for the Pi. This way it could write to storage even if the car is stopped and the drive turns off the ignition.

One thing I see that is a show stopper for a Car PC is boot time. Most take a bit to start up but a lot of Windows based. This may still make the Pi not as attractive as it sounds as a Car PC module. If it also cant be speed up on booting.

kaos
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Re: Rasberry Pi as in car pc

Mon May 21, 2012 1:38 pm

This is definitely on my to-do-with-Raspi list. Not the initial Raspi though; partly because I have higher priority projects for it, and partly because I already have a PC-based car computer that can serve me until I can got hold of more Raspis ;) . Here is a short description of my current system, in case it can give someone inspiration:

1. Based on a desktop PC, complete with mains power supply, which is fed from an inverter. This would obviously be replaced by the Raspi, powered by a 5V regulator, either a cannibalized USB lighter plug or a purpose designed circuit.
2. Uses a 2.5" laptop HDD for mass storage, as they are not as sensitive to vibration and shocks as 3.5" units. Note that this project is a few years old; these days I would go for a solid-state drive, and for the Raspi I might make do with the SD card.
3. Power is controlled by a PIC based circuit I made. This; a) notifies the PC (via serial connection) when ignition is switched off, b) gives the PC time to shut down before removing the power from the inverter, c) reports battery voltage to the PC (used for low battery shutdown), and d) incorporates watchdog functionality (restarts the PC if it stops responding). A small Visual Basic program running on the PC communicates with this circuit and initiates shutdown when appropriate.
4. Uses a secondary battery to cover the time when the car is being started, and during PC shutdown. This battery is also controlled from the aforementioned circuit.
5. Runs an audio player program that I wrote. Like the OP, I found most players to have a far to complicated and/or fiddly user interface for using while driving. I wrote my player in Visual Basic, and will obviously have to rewrite it for the Raspi. I'm leaning towards Python, but haven't quite decided yet. Amongst features of my player are:
a) Large buttons and large fonts, making it suitable for touchscreen operation, and reading key information (currently playing track et.c.) at a glance.
b) All buttons map to a numeric keypad, meaning that once you learn the layout, you can operate the player without looking away from the road.
c) Automatically cycles through my music collection, without having to set up playlists.

There is other stuff, like a USB GPS dongle, used for navigation, and a hefty volume button, made from a VHS recorder video head and the innards of a mouse (the computer peripheral; I have not yet had to resort to animal sacrifice to get this working), but this is the gist of it.

--
Best regards,
Kári.

chris1d
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Re: Rasberry Pi as in car pc

Sat Jun 23, 2012 2:30 pm

Hi guys,

I have got my pi. Installed Debian Squeeze and had a bit of a play. I've hooked it up to my indash screen in the car using RCA and power from the stereos USB. All works great. Now all I need is to make it a carpc. Any suggestions on a distro to use? I'm used to ubuntu, where everything is simple...download centre etc. Debian seems completely different! Where do I start??

relinquish
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Re: Rasberry Pi as in car pc

Fri Jul 20, 2012 7:51 pm

You could try OpenELEC(XBMC). I just did some quick google searches to get that result though. I am not sure about the boot times on it, but as a media center it looks pretty decent.
http://www.youtube.com/watch?v=Ao0JmzVh ... page#t=38s

How are the boot times on it with Debian?

techno
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Re: Rasberry Pi as in car pc

Tue Aug 07, 2012 2:07 pm

Although this thread is quite old, I'd like to step in and describe what I am currently trying to build with my RasPi. Maybe this could help others as well as solve the problems I'm facing at the moment...

I want to use the RasPi as an audio-only car entertainment system. Since we're using the Logitech Squeezebox Server software and several hardware clients at home, I decided to install the Squeezeplug image. Playback can be controlled with a fairly intuitive iPhone/iPad-App (actually not the free one from Logitech but the 3rd party app iPeng), so the RasPi won't need a display. To connect the RasPi with the iOS device a WLAN connection is needed. Since a stand-alone WLAN network in the car the iPhone is connected to would prevent the iPhone from accessing the internet, some sort of 3G connectivity is needed. After playing around a little bit with a UMTS USB stick hooked up with the RasPi (with embarrassing results), I put together the following setup:

1. Internet connectivity is provided by a fairly cheap 3G wireless router. As I already had a UMTS stick I choose the TP-Link TL-MR3020 for around 30 Euro. The RasPi is connected via ethernet while the iPhone uses the wireless LAN. An alternative would be to buy a mobile router with built-in 3G (like the Huawei E5) and a WLAN stick for the RasPi.

2. The music comes from a 2,5" USB HDD. An idea for the future is to wirelessly synchronize the mobile music collection with the collection on the file server at home when the car is parked within reach of the home WLAN.

3. The Squeezebox Server software (now called "Logitech Media Center") as well as a software squeezebox client are installed on the RasPi.

4. Everything is powered over a USB hub (which gets power from a 5A 12V/5V DC/DC converter). The hub in turn gets its USB uplink from the RasPi. (Yes, this looks strange but since the micro USB port on the RasPi is only for power, it works...)

On a first test, the playback started to cause problems after an hour. At the moment I don't know if this is a CPU issue or some other sort of problem caused by overheating - it was a very hot day. I decided to use the playback function of the iPeng app (streaming the audio to the iPhone) and it worked for the rest of the five hour trip.

The main problem with this setup is that there currently is no way to automatically power down the RasPi. I think there are three possibilities to solve this:

1. Setup a read-only system and hook up the whole thing to the switched 12V power supply. Problem: No way to save playlist even if the engine is turned off for just a minute. Also, synchronizing with the home collection get's somehow tricky.

2. Use one of the GPIO pins to (manually) give the RasPi the signal to power down and have a seperate on/off switch. Problem: You can't really tell if the RasPi is powered down correctly and are sitting around in the car waiting for the right moment to use the off-switch...

3. Building some sort of power-off delay switch which tells the RasPi (via GPIO) to shutdown, maybe even with the possibility to delay the shutdown for some time (e.g. when you are making a small break on a tour) or manually overriding the shutdown. I could also live with an off button (NOT a hardware off switch!) that triggers the shutdown and final poweroff. Problem: I do not have that much experience with this sort of electronics.

@kaos: From what I understood you already build a circuit that does something like what I described above. Would you mind posting the schematics?

Sorry for this long post, but maybe it helps anyone of us. :-)

techno

carpenike
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Re: Rasberry Pi as in car pc

Tue Aug 07, 2012 3:11 pm

techno wrote:Although this thread is quite old, I'd like to step in and describe what I am currently trying to build with my RasPi. Maybe this could help others as well as solve the problems I'm facing at the moment...
...
techno
Techno -- How would the iPhone handle a WLAN that only hands out an IP address? Not a default gateway or DNS server? From a networking perspective, a device should always use its default gateway, which would still be the 3G network as the WLAN didn't provide one.

Wolfram23
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Re: Rasberry Pi as in car pc

Tue Aug 07, 2012 3:51 pm

techno wrote:The main problem with this setup is that there currently is no way to automatically power down the RasPi. I think there are three possibilities to solve this:

1. Setup a read-only system and hook up the whole thing to the switched 12V power supply. Problem: No way to save playlist even if the engine is turned off for just a minute. Also, synchronizing with the home collection get's somehow tricky.

2. Use one of the GPIO pins to (manually) give the RasPi the signal to power down and have a seperate on/off switch. Problem: You can't really tell if the RasPi is powered down correctly and are sitting around in the car waiting for the right moment to use the off-switch...

3. Building some sort of power-off delay switch which tells the RasPi (via GPIO) to shutdown, maybe even with the possibility to delay the shutdown for some time (e.g. when you are making a small break on a tour) or manually overriding the shutdown. I could also live with an off button (NOT a hardware off switch!) that triggers the shutdown and final poweroff. Problem: I do not have that much experience with this sort of electronics.

@kaos: From what I understood you already build a circuit that does something like what I described above. Would you mind posting the schematics?

Sorry for this long post, but maybe it helps anyone of us. :-)

techno
I've been doing a lot of reading trying to figure out the best way to do this. My project is similar although I'm considering an LCD for GPS navigation. Regardless, here's some useful threads you might want to read:

http://www.raspberrypi.org/phpBB3/viewt ... =63&t=8820
http://www.raspberrypi.org/phpBB3/viewt ... 9&start=50
http://www.raspberrypi.org/phpBB3/viewt ... 0&start=75

Basically, there's talk about being able to use the GPIO pins to control wake/sleep mode. My plan is to build a circuit that takes the 12V line and drops it to 5V (using a switching transistor), and possibly run a parallel one off the Ignition line. The RPi could have constant power from the 12V batt line, but when ignition is turned off, there can be a timer chip that will turn off the 12V-5V converter chip as well as send the signal to the RPi to ender sleep mode. This way, the RPi will do any writes/dumps it needs to before losing power.

techno
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Re: Rasberry Pi as in car pc

Wed Aug 08, 2012 12:00 pm

carpenike wrote:Techno -- How would the iPhone handle a WLAN that only hands out an IP address? Not a default gateway or DNS server? From a networking perspective, a device should always use its default gateway, which would still be the 3G network as the WLAN didn't provide one.
This works indeed. The iPhone uses the WLAN for connection in the LAN (but it doesn't display the usual wireless symbol in the status bar and it shows a spinning wheel in the wireless settings next to the selected AP) and 3G for internet access. Good idea - don't know why I didn't come up with it myself... :-)

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