An anonymous reader writes "Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather? Here's a new video tutorial showing how to build your own computer-controlled LED array. You can code your own data feed, and just send it over a TCP socket. This looks like a fun weekend project for someone looking to get started with electronics by building something useful."
The question is if I can do this and have it run from my car. I put in predefined phrases, and depending on which switch I hit or button, it says them?
I've been thinking about one of these, but am a little worried that I'll end up getting shot or something when I piss off some idiot with a gun in the glovebox.
I've been thinking about one of these, but am a little worried that I'll end up getting shot or something when I piss off some idiot with a gun in the glovebox.
Don't worry, I won't shoot you. My permit is for hunting only.
Yes but be ready for a ticket and a "fix it ticket" to require removal of said device. Most states make it illegal for a illuminated sign to be in view of drivers on a moving vehicle. TAXI's and delivery cars have a waiver and the signs are not in the line of sight.
Well then, let's get a howto for making a mechanical sign. You know, like the signs made out of spinning, clacking scrabble pieces they used in train stations before LCD/LED tech (and still use in Europe)?
That would be awesome for both in-car use and the general steampunk feel.
I totally want to do this. So I can verbalize my frustrations with other drivers. Because right now all I have are Brights, Flash Brights, Honk, and Finger.
Everything else seems to not get recognized.
It would be great to ask people to pleas move out of the left lane. Request blinker changes. And comment on driving skill levels.
Caltrops. A big bag of them. Scatter behind your car to discourage tailgaters and those guys with jacked up trucks sporting 2 squillion candlepower fog lights. A bit indiscriminate, and somewhat low tech but definitely effective
Emp Gun. RF generating parts well shielded, waveguide pointing forward from under the hood. Somebody doing 50 in the passing lane? Push the big red button. Oh look, they're pulling over. Funny thing, no turn signals.
I picked up a kit at wal-mart that is designed for car use. It's a nice case with swivel feet (to allow hanging or standing mount) and comes with a remote control. Best of all, it was less than $20
The handy part of this device is that it has 8 memory locations for user-defined messages. Here are my saved messages.
1. Are you my proctologist? GET OUT OF MY ASS! 2. Got Low Beams? You're blinding me! 3. Your left turn signal is STILL on! 4. Your right turn signal is STILL on!
Sure, you can, but be careful. Department of Transportation has pretty strict rules about what kinds of lighting you can legally have on your vehicle.
Having a *ahem* friend who experienced problems with law enforcement over a very similar deployment to the one you're envisioning, I'd simply recommend caution.
Then again, the policies and practices of highway patrol / law enforcement in your state may vary. IANAL. This is not legal advice. Etc.
You can get scrolling marquee licence plate holders. [skymall.com] This is just the first link I found, I have seen them cheaper at places like Canadian Tire (which will probably confuse 98 per cent of readers here). But they do exist.
Still, making my own would be fun, I could put it up on the wall of my cubicle and do Facebook-style status updates with it. "Jabbrwokk is picking his nose and flicking it at the back of Jeff's head."
If you do use a DC psu make sure you buy one that is explicitly designed for use with automotive power. Automotive power while "nominally" 12V has a wide voltage range depending on current conditions (whether the engine is running, if so how fast, if not the condition of the battery etc)
I know LEDs are all the big rage now for displays. You see the seven-segment LED displays on calculators. But, while watching TV a year ago, I had an idea... what if I were to somehow connect up a TV to my computer? It took me a couple months, but I finally got it working... yes, a TV screen (well, actually it's not a TV anymore since I had to take out the receiver guts) connected to a computer. Since I use it to MONITOR the status of the various programs running on the computer, I'm going to call this contraption a "Monitor" I'll make millions! Also...I was out in my garage the other day cleaning and I found a dead mouse in the corner...and again, my mind is always working... I though...what would happen if I plugged this little guy's tail into the back of my computer, and replaced his legs with little motion-sensing wheels? I'll let you alll know the results when I finish my new invention. I'm calling it the Mobile Organic Universal Sensor Emulator, or MOUSE for short.
I was out in my garage the other day cleaning and I found a dead mouse in the corner...and again, my mind is always working... I though...what would happen if I plugged this little guy's tail into the back of my computer, and replaced his legs with little motion-sensing wheels? I'll let you alll know the results when I finish my new invention.
I remember when I first realized that you could double your row-column population. Then I extrapolated it to its logical conclusion... that you could connect n(n-1) leds where n is the number of control lines. I was so proud! Then in an unrelated search I learned that not only was this an established technique, but it even had a cute name: Charlieplexing.
They have a lot more LEDs than controller outputs and use tricks to multiplex. But this means each LED only is turned on for a few milliseconds at a time. Can you get out a reasonable intensity this way?
I was thinking about this. (Also, not being an electrical engineer by any means.) Could you place a relatively small capacitor on each LED to increase the burn time?
My boss gave me a USB-powered LED screen as a Christmas present, aimed as one of those endless throwaway novelty USB gadgets (other one was a whack-a-mole game. It's far smaller than the one in TFA though, about the size of a pack of smokes. Still, it scrolls text and displays bitmaps pretty niftily. The font and configuration files are stored in plain text (the scroll speed was a fun one to tweak) so the option for even-triggered (e.g. server in trouble) scripting is there.
Granted, there's no geek cred from building it yourself, but at least the soft aspect is similar. Now if only there support calls would stop coming in so fast that I had time to play with the thing...
We had tuned the www.NerdKits.com [nerdkits.com] site to survive slashdottings with its old PHP backend, but we recently started experimenting with some Django [djangoproject.com]. Django is great as a programming framework, but I suppose we have discovered that our tuning of the server settings isn't quite up to handling a Slashdotting! We've temporarily disabled that stuff so the site is back and running. My apologies for the downtime.
I wrote the firmware for one of these thingies about 20 years ago. (I did it for a company that was in the electronic sign business - they made those flip-dot signs you see on buses, subways, etc.) I was lucky to have been given pretty-much complete flexibility in the firmware design, including functionality.
We used a Z-80 as the controller. The display panel was built on two identical circuit boards - they could be chained endlessly, though I don't think they ever made a wider model. It was a BIG DEAL getting the component-stuffing machine to place all those LEDs! (This wasn't surface mount, but through-holes.)
Each display panel had a shift-register - one bit per column, and just passed the bits down to the next panel. The CPU banged out bits to the shift register until the row was filled, and then enabled the row driver. Yes, we were careful to avoid refresh rates that could be a problem for epileptics.
They insisted on an asymmetrical case design - the case had a "base" that it could sit on on a desk or other surface, or it could be mounted from a ceiling. Only problem was, if it was mounted from a ceiling, it was then "upside down" and the characters had to be flipped. They were going to put a switch on the back, but I figured they would get support calls from people who wouldn't read the manual, so at my suggestion they put in a mercury switch, mounted at a 45 degree angle. The processor read the mercury switch and flipped the characters if needed.
We used an RCA flat-panel keyboard with a custom overlay. I designed icons for the various effects, and the icons were printed over letters and accessed during programming with the "ALT" key. The icons appeared on screen when in programming mode. There was a simple text-editor, and some icons accepted parameters (for example, transition effects all took an optional transition time parameter) I implemented a simple macro system [macro_name] so that text snippets could be stored and referenced from within messages. You could store multiple messages and select the one or ones to be displayed, or a timer could trigger them.
There was also a serial port through which it could be programmed. I think the idea was that it could be programmed remotely in, say, a store location. I don't know if this was ever implemented, but I vaguely recall that the idea was to send a subcarrier signal on a muzak station (that stores would already have access to) that would be decoded and passed to the serial port.
I never did install one of these in the back window of my car. I certainly entertained the thought, though.:)
I had one of the pre-production samples kicking around for years, and finally discarded it. Yea, I wish I still had that Schelbi Mark 8 too... (Mine was build on a wirewrap board - somebody was selling a kit with a wirewrap board and all the parts).
(Would be interesting to compare the designs. However, the site referenced by the article has been slashdotted...)
To clarify, each display board had a number of serial-in parallel-out TTL shift registers across the top of the board. The parallel outputs went to latches (or maybe the shift registers had latched outputs?) which went to the column drivers. I think there were about 800 LEDs total on the two boards, so quite a bit larger display than this kit! The addressing technique used by the kit would be impractical for this size of display.
It would bang out the bits, latch the outputs, turn on the row driver, and star
Excellent...that way, if the bus ever flipped over, one would still be able to read where it was going to know whether they needed to call a taxi or just keep waiting. Well done!
I can have a wall of these LEDs randomly blinking, then my computer room looks like some "secret headquarters" with big monoliths of useless lights, just like in science fiction films of yesteryear. Now only if I could get that sound loop of the "computer beeping" stock audio it would be complete. Maybe a tractor feed printer on a stand, aww yeah.
Shame the TCP/IP stack isn't on the microcontroller. Putting uIP on there, or grabbing bits from my stack (http://www.mcternan.co.uk/MAD/) would be awesome.
"Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather?
Yeah, I used to wish exactly that, but I took the easy (well, I did have to reverse-engineer the serial protocol, but that was fairly easy) way out and went to the hardware store and bought one. It's been serving my team very well since then [f-secure.com].:-)
I found a couple hundred big 8x8 matrix LED displays on ebay for way too little money last year, and I'm working on a low-resolution but huge flat TV for video fun at Burning Man this summer.
But I'm going with a standard video signal such as your DVD player makes, so it will display shades of gray for realistic reproduction of video images.
It's a bit tricky to make a TV display out of LEDs, but I found that using a couple dozen FPGAs makes the job a lot easier. Pulse width modulation provides the brightness control per pixel.
It should be a lot of fun when completed. I';ll post photos.
I got creative with our HP printers a few years ago,
trying to see what it would take to get some of our
programming team to speak up, or to say anything without
being explicitly told what to say. You know the type, I'm sure...
The first person to notice INSERT COIN was my former boss, who spluttered and then demanded an
explanation of our sysadmin. Sysadmin claimed total ignorance, but admitted it might be a good idea. I heard this going on and after I regained my
composure went in to his office and spill
Now... (Score:5, Interesting)
Re: (Score:2)
Re:Now... (Score:5, Funny)
There are actually already license plate frames with little LED displays built in that allow you to do this.
Yeah, but it doesn't quite scream "Nerd" as hard as when you built it yourself.
Parent
Re:Now... (Score:5, Funny)
Yes, they scare me...
Parent
Re: (Score:2)
Re: (Score:2, Funny)
Step One Rob Bank
Re: (Score:2)
One question - will this get me laid?
Re: (Score:2)
In general, this depends almost entirely on your standards.
Re: (Score:2)
those things scream ghetto more then nerd.
Why discriminate to only white nerds? There can be Ghetto Nerds, too!
Re: (Score:2, Informative)
Here you go:
http://www.thinkgeek.com/gadgets/car/afe6/ [thinkgeek.com]
I've been thinking about one of these, but am a little worried that I'll end up getting shot or something when I piss off some idiot with a gun in the glovebox.
Re: (Score:2)
I've been thinking about one of these, but am a little worried that I'll end up getting shot or something when I piss off some idiot with a gun in the glovebox.
Don't worry, I won't shoot you. My permit is for hunting only.
Re:Now... (Score:5, Informative)
Yes but be ready for a ticket and a "fix it ticket" to require removal of said device. Most states make it illegal for a illuminated sign to be in view of drivers on a moving vehicle. TAXI's and delivery cars have a waiver and the signs are not in the line of sight.
Parent
Re: (Score:2)
Well then, let's get a howto for making a mechanical sign. You know, like the signs made out of spinning, clacking scrabble pieces they used in train stations before LCD/LED tech (and still use in Europe)?
That would be awesome for both in-car use and the general steampunk feel.
Re: (Score:3, Funny)
Re:Now... (Score:4, Funny)
Emp Gun. RF generating parts well shielded, waveguide pointing forward from under the hood. Somebody doing 50 in the passing lane? Push the big red button. Oh look, they're pulling over. Funny thing, no turn signals.
Parent
Re: (Score:2)
I picked up a kit at wal-mart that is designed for car use. It's a nice case with swivel feet (to allow hanging or standing mount) and comes with a remote control. Best of all, it was less than $20
The handy part of this device is that it has 8 memory locations for user-defined messages. Here are my saved messages.
1. Are you my proctologist? GET OUT OF MY ASS!
2. Got Low Beams? You're blinding me!
3. Your left turn signal is STILL on!
4. Your right turn signal is STILL on!
The other 4 slots remain empty unt
Re: (Score:2)
Sure, you can, but be careful. Department of Transportation has pretty strict rules about what kinds of lighting you can legally have on your vehicle.
Having a *ahem* friend who experienced problems with law enforcement over a very similar deployment to the one you're envisioning, I'd simply recommend caution.
Then again, the policies and practices of highway patrol / law enforcement in your state may vary. IANAL. This is not legal advice. Etc.
Already exists (Score:2)
You can get scrolling marquee licence plate holders. [skymall.com] This is just the first link I found, I have seen them cheaper at places like Canadian Tire (which will probably confuse 98 per cent of readers here). But they do exist.
Still, making my own would be fun, I could put it up on the wall of my cubicle and do Facebook-style status updates with it. "Jabbrwokk is picking his nose and flicking it at the back of Jeff's head."
Re: (Score:2, Insightful)
Make sure you get one printed in reverse for the front bumper. ;)
Re: (Score:2)
running off a power inverter hacked into the vehicles 12-volt power
No need to hack. They already have DC Power Supplies just for this purpose:
http://www.powerstream.com/mini-itx.htm [powerstream.com]
http://www.short-circuit.com/ [short-circuit.com]
Re: (Score:3, Informative)
If you do use a DC psu make sure you buy one that is explicitly designed for use with automotive power. Automotive power while "nominally" 12V has a wide voltage range depending on current conditions (whether the engine is running, if so how fast, if not the condition of the battery etc)
Yes but... (Score:4, Funny)
Email? Server up time? Please (Score:2)
Re: (Score:2, Insightful)
I've done something similar but more advanced. (Score:5, Funny)
I know LEDs are all the big rage now for displays. You see the seven-segment LED displays on calculators. But, while watching TV a year ago, I had an idea... what if I were to somehow connect up a TV to my computer? It took me a couple months, but I finally got it working... yes, a TV screen (well, actually it's not a TV anymore since I had to take out the receiver guts) connected to a computer. Since I use it to MONITOR the status of the various programs running on the computer, I'm going to call this contraption a "Monitor"
I'll make millions!
Also...I was out in my garage the other day cleaning and I found a dead mouse in the corner...and again, my mind is always working... I though...what would happen if I plugged this little guy's tail into the back of my computer, and replaced his legs with little motion-sensing wheels? I'll let you alll know the results when I finish my new invention. I'm calling it the Mobile Organic Universal Sensor Emulator, or MOUSE for short.
Re:I've done something similar but more advanced. (Score:4, Funny)
Shampoo, Is that you?
Parent
Re: (Score:2)
Yes, and then I went into *my* garage and had fun building an LED marquee :-)
Re: (Score:2)
was more fun reading what you wrote the article
Re: (Score:2)
I was out in my garage the other day cleaning and I found a dead mouse in the corner...and again, my mind is always working... I though...what would happen if I plugged this little guy's tail into the back of my computer, and replaced his legs with little motion-sensing wheels? I'll let you alll know the results when I finish my new invention.
Frankenrat will kill us all, you fool!
It's so cute... (Score:5, Informative)
I remember when I first realized that you could double your row-column population. Then I extrapolated it to its logical conclusion... that you could connect n(n-1) leds where n is the number of control lines. I was so proud! Then in an unrelated search I learned that not only was this an established technique, but it even had a cute name: Charlieplexing.
There's a neat little story here:
http://www.maxim-ic.com/appnotes.cfm/an_pk/1880 [maxim-ic.com]
Low intensity??? (Score:3, Insightful)
Re:Low intensity??? (Score:4, Funny)
Sure, just up the current. The LEDs will be brighter for a shorter duration and it will look the same.
Not sure I like the idea of draining so much current through the uC though...
=Smidge=
Parent
Re: (Score:2)
Not if you scale it beyond a certain level... as stated in the article, the author feels that this particular arrangement allows for good intensity.
You could, theoretically, use capacitors to increase the intensity.
Additionally, if you wanted to use multiple or a more powerful controller you could do that too.
Like with any electronic design, there are sacrifices to be made to keep things simple.
Re: (Score:2)
I was thinking about this. (Also, not being an electrical engineer by any means.) Could you place a relatively small capacitor on each LED to increase the burn time?
Small version (Score:3, Interesting)
My boss gave me a USB-powered LED screen as a Christmas present, aimed as one of those endless throwaway novelty USB gadgets (other one was a whack-a-mole game. It's far smaller than the one in TFA though, about the size of a pack of smokes. Still, it scrolls text and displays bitmaps pretty niftily. The font and configuration files are stored in plain text (the scroll speed was a fun one to tweak) so the option for even-triggered (e.g. server in trouble) scripting is there.
Granted, there's no geek cred from building it yourself, but at least the soft aspect is similar. Now if only there support calls would stop coming in so fast that I had time to play with the thing...
Re: (Score:2)
Do you have a link to that small USB-powered LCD screen?
Re: (Score:2)
http://www.dreamcheeky.com/index.php?pagename=product&pid=52 [dreamcheeky.com]
It's from Dream Cheeky, a company that seems to specialise in USB-powered anything...
Re: (Score:2)
You weren't kidding when you said "USB-powered anything".
Pinball games uses the same row-column setup to dr (Score:2)
Pinball games uses the same row-column setup to drive lights and read switches.
Not Slashdotted Anymore! (Score:5, Informative)
Hi all,
We had tuned the www.NerdKits.com [nerdkits.com] site to survive slashdottings with its old PHP backend, but we recently started experimenting with some Django [djangoproject.com]. Django is great as a programming framework, but I suppose we have discovered that our tuning of the server settings isn't quite up to handling a Slashdotting! We've temporarily disabled that stuff so the site is back and running. My apologies for the downtime.
- The NerdKits Team
Next Week on NerdKits (Score:3, Funny)
Python fix to make restart easier (Score:2)
Put this at the beginning after s is assigned, to reduce the time you have to wait between restarts for old connections to go away.
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
Ah, brings back memories... (Score:5, Interesting)
I wrote the firmware for one of these thingies about 20 years ago. (I did it for a company that was in the electronic sign business - they made those flip-dot signs you see on buses, subways, etc.) I was lucky to have been given pretty-much complete flexibility in the firmware design, including functionality.
We used a Z-80 as the controller. The display panel was built on two identical circuit boards - they could be chained endlessly, though I don't think they ever made a wider model. It was a BIG DEAL getting the component-stuffing machine to place all those LEDs! (This wasn't surface mount, but through-holes.)
Each display panel had a shift-register - one bit per column, and just passed the bits down to the next panel. The CPU banged out bits to the shift register until the row was filled, and then enabled the row driver. Yes, we were careful to avoid refresh rates that could be a problem for epileptics.
They insisted on an asymmetrical case design - the case had a "base" that it could sit on on a desk or other surface, or it could be mounted from a ceiling. Only problem was, if it was mounted from a ceiling, it was then "upside down" and the characters had to be flipped. They were going to put a switch on the back, but I figured they would get support calls from people who wouldn't read the manual, so at my suggestion they put in a mercury switch, mounted at a 45 degree angle. The processor read the mercury switch and flipped the characters if needed.
We used an RCA flat-panel keyboard with a custom overlay. I designed icons for the various effects, and the icons were printed over letters and accessed during programming with the "ALT" key. The icons appeared on screen when in programming mode. There was a simple text-editor, and some icons accepted parameters (for example, transition effects all took an optional transition time parameter) I implemented a simple macro system [macro_name] so that text snippets could be stored and referenced from within messages. You could store multiple messages and select the one or ones to be displayed, or a timer could trigger them.
There was also a serial port through which it could be programmed. I think the idea was that it could be programmed remotely in, say, a store location. I don't know if this was ever implemented, but I vaguely recall that the idea was to send a subcarrier signal on a muzak station (that stores would already have access to) that would be decoded and passed to the serial port.
I never did install one of these in the back window of my car. I certainly entertained the thought, though. :)
I had one of the pre-production samples kicking around for years, and finally discarded it. Yea, I wish I still had that Schelbi Mark 8 too... (Mine was build on a wirewrap board - somebody was selling a kit with a wirewrap board and all the parts).
(Would be interesting to compare the designs. However, the site referenced by the article has been slashdotted...)
Re: (Score:3, Informative)
To clarify, each display board had a number of serial-in parallel-out TTL shift registers across the top of the board. The parallel outputs went to latches (or maybe the shift registers had latched outputs?) which went to the column drivers. I think there were about 800 LEDs total on the two boards, so quite a bit larger display than this kit! The addressing technique used by the kit would be impractical for this size of display.
It would bang out the bits, latch the outputs, turn on the row driver, and star
Re: (Score:3, Funny)
Well done!
Cool (Score:2)
I can have a wall of these LEDs randomly blinking, then my computer room looks like some "secret headquarters" with big monoliths of useless lights, just like in science fiction films of yesteryear. Now only if I could get that sound loop of the "computer beeping" stock audio it would be complete. Maybe a tractor feed printer on a stand, aww yeah.
serial interface (Score:2)
Shame the TCP/IP stack isn't on the microcontroller. Putting uIP on there, or grabbing bits from my stack (http://www.mcternan.co.uk/MAD/) would be awesome.
I took the lazy path... (Score:5, Interesting)
"Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather?
Yeah, I used to wish exactly that, but I took the easy (well, I did have to reverse-engineer the serial protocol, but that was fairly easy) way out and went to the hardware store and bought one. It's been serving my team very well since then [f-secure.com]. :-)
I'm designing an LED TV set - 48", red LED (Score:3, Interesting)
I found a couple hundred big 8x8 matrix LED displays on ebay for way too little money last year, and I'm working on a low-resolution but huge flat TV for video fun at Burning Man this summer.
But I'm going with a standard video signal such as your DVD player makes, so it will display shades of gray for realistic reproduction of video images.
It's a bit tricky to make a TV display out of LEDs, but I found that using a couple dozen FPGAs makes the job a lot easier. Pulse width modulation provides the brightness control per pixel.
It should be a lot of fun when completed. I';ll post photos.
SIT VIS TECUM (Score:3, Funny)
I got creative with our HP printers a few years ago, trying to see what it would take to get some of our programming team to speak up, or to say anything without being explicitly told what to say. You know the type, I'm sure...
The first person to notice INSERT COIN was my former boss, who spluttered and then demanded an explanation of our sysadmin. Sysadmin claimed total ignorance, but admitted it might be a good idea. I heard this going on and after I regained my composure went in to his office and spill