My first CarPC in my Subaru Legacy (Estate) - With LED sign!

AvWuff · 08-07-2008, 12:15 AM

Hi everyone; I'm new here.

I think my Car PC project is ready enough that I feel confident showing it off on this site. Try not to chew me out too much; it's my first one!

Probably the best way to introduce it is to link to this video I made, which I've uploaded to YouTube:

AvBrand Car PC demo

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(Make sure you hit 'watch in high quality').

Here's a photo of the installation in the rear of my car, underneath the cargo panel above the spare tire:

Some points:

I'm using the Xenarc MDT-X7000, and I've got:
Voice Control
GPS Nav
Traffic cameras & verbal traffic reports
Speed Controlled Volume
Music management & playlist synchronization with my home
Reverse camera (w/ reverse gear integration)
LED message sign

There's a ton more photos, information, and stuff on my site:
http://www.avbrand.com/projects/carpc/

You guys are veterans, so I'll try to preemptively answer some of the more obvious questions I'm sure to get:

Why are you using a laptop?
Choosing a laptop has introduced some unique problems, but I did it because it's an integrated device that's designed to be shaken about, manhandled, etc. It's also got a battery built-in. I've done almost 4000 km with this CarPC and the laptop has not missed a beat.
What's up with the Linksys router?
It may sound totally retarded, but the only thing the router does right now is send a Wake-On-Lan packet to turn on the laptop. It was the cheapest ($30) way I could come up with to have the laptop power on when the car does. (Think about it -- can you think of a better way?)
Is that LED sign legal?
It is in Ontario! You'll have to check the regulations in your state or province. Ontario allows "intermittent" Amber lights facing the rear.

Anyway, the car PC works very well for me. I've put a lot of time and effort into it and am very happy with how it's turned out.

I'd love to hear your thoughts and comments!

Cheers,
-av

Bugbyte · 08-07-2008, 12:35 AM

Well done! More info on the sign and how it works and the voice control, please.

AvWuff · 08-07-2008, 12:45 AM

You got it! :-)

The LED sign

To be visible in sunlight, the sign needs to use "High-Brightness" LED's. Indoor 3-color LED signs just won't cut it. Some manufacturers call these "Semi-outdoor" signs, others call them "window displays". The theory is that you hang them in your shop window facing outside.

I bought the NS-500UA from AffordableLED for $229:
http://www.affordableled.com/11300100p004.html
(it's made by nutrontech.com)

I knew the sign would be crap compared to my much fancier Alpha (a leading manufacturer) sign, but it was the right size and the price was decent. Also, it uses high-brightness Amber LEDs.

It has a serial interface. The software it comes with is worthless, but spying on the serial port while using the software allowed me to reverse-engineer the protocol. Soon I had written my own library for communicating directly with the sign. I plan to release this library as open-source on my website.

Building the on-screen menu of messages and integrating the keyboard was trivial. It works quite well mounted on the car.

However, all is not rosy: In using this sign, I've discovered that 90% of the time, the people behind you don't pay attention to the car in front (you). They look at their phones, out the window, at the passenger, at the dash, at their feet... but never ahead. So despite the bright flashing messages, people are oblivious to them.

If you are interested in adding such a sign to your car, check your local state's highway laws first. I happen to know that in Vermont the sign would be fully legal, but this isn't the same in every state. It could be connected to a car PC, but the protocol is simple enough that you could implement it into an Arduino and have five or six buttons to choose a message.

------------------

The voice control:

This part is really simple. I'm using the Andrea Soundmax stereo array microphone, mounted to my rear-view mirror. For software, I'm using the Microsoft Speech SDK. This SDK makes adding speech support to your apps so bloody easy, it's ridiculous. It's one line of code per command, plus some code you copy-paste from the samples for the initialization.

The green button is wired into a relay which trips an input on an Arduino board in the trunk. The arduino is programmed to send a byte out the serial port when that input trips, which tells my front-end that the button was pressed.

Pressing the button pauses any music that might be playing, plays the "listening" noise, and mutes the audio. You can cancel any command (if it misheard you) by pressing the button again before it finishes talking.

I hope this answers your questions!

-av

colin · 08-07-2008, 03:16 AM

Man, I just spent like 3 hours on your website and the urban exploration one!
I just followed a bunch of links and a few hours later, at 3:15AM here I am with a tab I completely forgot about -- MP3car.

Awesome haha

we87 · 08-07-2008, 08:09 AM

Really nice install!

What are you using for your Voice Commands? What software are you using...

phall3n · 08-07-2008, 08:57 AM

Very nice!! I am a fan of all of your projects listed on your sites. You opened my eyes to the potential of LED displays. When the time comes for me to begin my carputer, I will resort back to your project for motivation and ideas.

Keep up the good work and keep us updated if you add anything new to your vehicle. Can't wait to see your next project.

AvWuff · 08-07-2008, 09:10 AM

Quote: Originally Posted by we87

What are you using for your Voice Commands? What software are you using...

Well, I'm using my own software for the actual control, with the Microsoft Speech SDK to do the grunt work as I said above.

Thanks for all your kind comments, everyone!

monkeyracer · 08-07-2008, 12:49 PM

Quote: Originally Posted by AvWuff

[*]What's up with the Linksys router?
It may sound totally retarded, but the only thing the router does right now is send a Wake-On-Lan packet to turn on the laptop. It was the cheapest ($30) way I could come up with to have the laptop power on when the car does. (Think about it -- can you think of a better way?)

I can think of a few ways to get the laptop to power on without the router.

A fellow forum member has designed a module for this exact reason:
Auto Turn-On Module

You can wire a CAT-5e cable to a relay that sends the "packet data" to the lan port for WOL.

But, it seems the router works for you, so that seems like it will do just fine. I think you could have purchased a wired router for a little less $, and would have had something with a little smaller footprint.

So I assume you have the router on a relay, so that it only powers up when the car does, and once the router receives power it sends the link packet to the lan port right?

blbrchnk · 08-07-2008, 12:58 PM

Quote: Originally Posted by AvWuff

What's up with the Linksys router?
It may sound totally retarded, but the only thing the router does right now is send a Wake-On-Lan packet to turn on the laptop. It was the cheapest ($30) way I could come up with to have the laptop power on when the car does. (Think about it -- can you think of a better way?)

Could you instead do something with the little tab that gets pushed down when you close the screen? I know this is used on most laptops so it can detect the screen shutting and either turn it off/hibernate/standby etc. Just a thought.

AvWuff · 08-07-2008, 01:21 PM

The thing is, I didn't want to open up or hack up the laptop, since it was brand new and I wanted to be able to return it or resell it if it didn't work out.

The "Auto Power Turn On Module" you've linked there is really just a relay that trips the power switch -- I could have done that, for sure, but it would involve opening up the laptop and soldering wires to the button.

I looked into a device that could send WOL packets on command, but it would have cost about $60-100 -- more than double the $35 I spent on the Linksys Router.

Anyway, yes, the router is on the relay that switches on when the car does, and after a few seconds of boot cycle it sends the WOL packet. I'm using the custom DD-WRT firmware to do this.

Cheers,
-av

Meltz014 · 08-12-2008, 09:02 PM

The sign is pretty cool...you should put one in your dash facing forward, but mirror it so people can read it in front of you - you could say stuff like "Speed limit is 55, moron!" or whatever. :P

AvWuff · 08-13-2008, 10:28 AM

Quote: Originally Posted by Meltz014

The sign is pretty cool...you should put one in your dash facing forward, but mirror it so people can read it in front of you - you could say stuff like "Speed limit is 55, moron!" or whatever. :P

Haha, well, that would require someone to look in their rear-view, something that people do even less!

Seriously, though, I've thought about it, but then I realized that for people in front you've got a horn and highbeams!

Cheers,
-av

grinthock · 08-17-2008, 10:37 PM

Well done Av... I helped Av do some of the automotive electronics side of this install, and it actually went pretty well.

The magic glue that makes it all work so amazing is his software, being that he's an excellent programmer, the software does even more than you can even see here! The integration with the home network for sync of music automagically, the traffic camera system and how that actually works, it's all quite amazing.

The best thing we learned during this install is -- planning is everything. Sit down and think about what you want to do - and plan it. We did. As a result when install day came and went, everything was in - installed - and worked exactly as we planned.

the only gotcha we had was, we ended up with 2 parasitic voltage leaks that went back through USB, and caused the master system relay to stay on... But a simple diode fixed that.

flowidc · 09-19-2008, 03:03 PM

Well done. What software are you using for the traffic cameras? Do they automatically update according to your gps coordinates? There are around 50 or more traffic cams where I live. I am using enforcer's traffic cam software to view them but I can only set up 18 cameras in his program and they are static (meaning they do not change according to my coordinates). I would eventually like to have a program that is able to pick up the traffic cams closest to me or in the direction that I am heading and display on the screen.

-Ricky

AvWuff · 09-19-2008, 03:20 PM

I used my own software. It's relatively simple -- I programmed in all of the traffic cameras's co-ordinates and URL into an XML file. You can see the file here:

http://car.avbrand.com/cams/trafficcams.xml

For each camera, I specified it's location, the URL of it's image, and which road it appears on.

Originally, I had the screen simply show me cameras if I was close enough, but they annoyingly popped up constantly when I was going near (but not on) the highway. So I also programmed in some lines representing the major highways, and now the software only shows the cameras when I am on the highway. (You can see this in the XML also).

The software does some math to only show you cameras that are in front of you, and generally tries to only show you cameras for the road you are driving on. It works quite well!

Thanks for your interest :-)

-av

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