Well done! More info on the sign and how it works and the voice control, please.
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:
(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:
There's a ton more photos, information, and stuff on my site:
- 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
You guys are veterans, so I'll try to preemptively answer some of the more obvious questions I'm sure to get:
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.
- 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.
I'd love to hear your thoughts and comments!
Last edited by Enforcer; 11-13-2011 at 05:26 PM. Reason: Change tags on video to the new ones.
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:
(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!
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.
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.
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?
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.