A Giant DIY LED Display

smf28 writes "Dheera Venkatraman has created a giant DIY LED display featuring 36 blue Luxeons in a 6x6 array on the windows of Simmons Hall, an undergraduate dormitory at MIT famous (or infamous, if you wish) for its design. Recent uses included welcoming students in September, Pirate Day, and others."

Comments

Microchip PICs

[bhima]

Another fine use for PICs. I love these things...

Re:Microchip PICs

[Anonymous Coward]

Fine use for any uC.

Check out Atmel AVRs. They're especially good if you've ever needed to do I2C and really didn't want to write a bit-banger system. They also have on-die oscillators, which could have removed the external crystal in their schematic.

~AVR Fan Boy

Re:Microchip PICs

[Alioth]

I think some PICs also have internal oscillators - not that I've yet built anything that uses a uC (but I've been looking around for my next project).

Re:Microchip PICs

[dheera]

Many PICs have internal oscillators, but they are RC which isn't very stable, and def. not good enough for RS232 or any other communication - especially when the temperature of the room fluctuates a lot...

Re:Microchip PICs

[juniorkindergarten]

Actually, I work with Microchip's 16f819, and that has a built in crystal running at 8 Mhz, and is extremely stable with temperature (automotive).

Re:Microchip PICs

[stevenm86]

On the contrary. The RC oscillators work quite well with RS232. Besides, some of the 18F series have internal RC and crystal oscillators, and a built in USB peripheral. The 30F I don't think have USB, but they have a ton of memory and an FPU.

Re:Microchip PICs

[Tyge]

Interesting post date. Oct 21 2006. Edison's bulb was invented Oct. 21 1879 :)

Re:Microchip PICs

[Eternauta3k]

Well, you could read the last byte before flashing the pic. It contains a calibration number for the rc oscillator, if I remember right.

Re:Microchip PICs

[marcansoft]

RC causes trouble with RS232 if it isn't calibrated right. Forget about using USB with it, it won't work.

I2C, OTOH, is perfectly fine. RC oscillators are perfectly fine for synchronous comms, since they don't depend on a precise clock rate. And most newer PICs have I2C built-in, so no need to bitbang.

Re:Microchip PICs

[SageMusings]

Nope. That's why you resynch constantly on the pre-amble err...start bit...
RC osc's are just fine.

Cheers.

Slashdotted

[Anonymous Coward]

Trust slashdot to put the lights out! Someone should build a mirror array.

Re: Slashdotted

[dheera]

oh god. mirror: http://web.mit.edu/dheera/www/simdisplay.php.html

Re:Slashdotted

[suv4x4]

Trust slashdot to put the lights out! Someone should build a mirror array.

You know, people like you who keep reminding us of the "slashdot effect" always get modded up since it flatters the slashdot readers that theya re part of something big, the colective power of which can bring a server down.

Truth is the slashdot effect is nothing like what it used to be when blog had decent articles (versus unchecked factas, duped, misinformation etc. in massive quantities).

And second, you can bring a small server, or a site on a shared server relatively easily with couple of hundred people visiting at once. The key is they visit at once, since if they didn't, the same server would take easily a 50-100k people during the span of a day.

Re:Slashdotted

[dheera]

I looked at my logs. It's probably the initial rush of visits in the first couple of minutes. A potential "slashdotting-protection" system that could be implemented by large sites is to select different IP ranges at random and serve up the site with a 0, 30, 60, 90, 120, 150, or 180 second delay based on the incoming IP range (i.e. if you're in the IP range corresponding to the 120 second delay, the article doesn't even show up for you until 120 seconds after it has been posted. I don't know if this has other moral issues, or if it's Slashdot's responsibility to care, but it's just a thought about a hypothetical solution.

Re: Slashdotted

[gaber1187]

speaking of "oh god"... oh god that building is ugly... I guess at night its not so ugly, but man... anybody ever seen that thing? jeez... the eecs building is kinda funky, but at least its not "ugly"...

Re:Slashdotted

[suv4x4]

I looked at my logs. It's probably the initial rush of visits in the first couple of minutes. A potential "slashdotting-protection" system that could be implemented by large sites is to select different IP ranges at random and serve up the site with a 0, 30, 60, 90, 120, 150, or 180 second delay based on the incoming IP range (i.e. if you're in the IP range corresponding to the 120 second delay, the article doesn't even show up for you until 120 seconds after it has been posted. I don't know if this has other moral issues, or if it's Slashdot's responsibility to care, but it's just a thought about a hypothetical solution.

Good idea. It can be cookie/user based as well. If more than X users see an article at once, next users see it after 20 second delay, then if there's a rush again, there's another 20 second delay.

Of your suer has seen the article, he gets to see it again when he visits Slashdot. Unlogged users will need the cookie.

This means if you're unlogged AND disable cookies, when you see an article being rushed, you may refresh and see it disappear.
But no big deal, it'll show a bit later again so...

And yea, I think it's Slashdot's responsibility, part of it is the absurd fun Slashdotters have when they bring a server down. There's nothing fun about that, someone has to fix it. The readers can't fix it: they see an article and click. Slashdot can.

Re:Slashdotted

[Dirtside]

Truth is the slashdot effect is nothing like what it used to be when blog had decent articles (versus unchecked factas, duped, misinformation etc. in massive quantities).

Go back and browse slashdot articles from two, four, six, or even eight years ago. The quality hasn't gotten worse. Or really changed much at all, for that matter (Roland Piquepaille notwithstanding).

Hackers

[UnderDark]

Reminds me of whay 0cool(Crash Override) did in the movie "Hackers" with the building lights: spelt out "Crash and Burn"

Re:Hackers

[Anonymous Coward]

Looks like a project out of the book Hardware Hacking Projects for Geeks.

Nothing to see here, move along.

Re:Hackers

[Joe The Dragon]

Building do that for real like saying go bears in chicago.

Re:Hackers

[Anonymous Coward]

Um... that wasn't them. That was their friends.

Blinkenlights?

[Animaether]

http://www.blinkenlights.de/index.en.html

And I *know* there was a Dutch team that did much the same as well, and a Dutch commercial venture (was it KPN - Dutch telecom?) has one still up and running, I think.

But I guess they didn't use the Ooh! Shiny! blue LEDs :)

BlinkenLights and some other examples

[xmas2003]

I have some other examples of projects like this listed here. Very cool job by the MIT guys ... now they just need to add some more of 'em in all of the windows and provide the ability to generate alphanumber (or image) messages that can be uploaded from the Internet - heh, heh! ;-)

Re:BlinkenLights and some other examples

[houghi]

now they just need to add some more of 'em in all of the windows

Where can I fnd a building with 640x480 windows?

Re:BlinkenLights and some other examples

[Usquebaugh]

Then set up RGB in each window :-)

Re:BlinkenLights and some other examples

[PhilDEE]

... now they just need to add some more of 'em in all of the windows and provide the ability to generate alphanumber (or image) messages that can be uploaded from the Internet - heh, heh! ;-)

But thing is, will it support ClearType?

Potential Income Opportunity

[Critical Facilities]

If they're really clever, they could sell advertising and offset the cost of adding to the array. I'm betting companies like Intel, AMD, IBM, Dell, etc would be willing to part with a little cash for some display time on a building/billboard at MIT.

Re:Potential Income Opportunity

[JoshJ]

I'd much rather they not corrupt the project by doing that. It's awesome as is, if it turned into yet another kind of lame advertising, that'd suck.

Re:Potential Income Opportunity

[Critical Facilities]

From TFA:
Acknowledgements Thanks to everyone on the Simmons Rush team that helped with the installation including soldering, duct taping, and cutting. Thanks to Simmons Hall for providing the funding for this project.

While I agree that "overcommercialization" of this would indeed suck, I was thinking of it more in a sponsorship type of income opportunity. You know, getting a PC vendor/LED manufacturer to provide parts at cost, leasing equipment at preferred rates, etc.

Re:Potential Income Opportunity

[fredcai]

The array cost less than 150 and was sponsored. Evil advertising unnecessary.

Too bad

[fuckingsound]

"We need babes now!" doesn't fit on a 6x6 array.

Re:Too bad

[smf28]

It is animated and scrolls text or any 6x6 animation; see the video on the link.

Re:Too bad

[suv4x4]

It is animated and scrolls text or any 6x6 animation; see the video on the link.

As you see in the video is pretty hard at times to follow a scrolling text on a 6x6 display. Now make it 12x6 or 10x6 and it might work.

Of course, this is not meant to be useful, it's meant to be cool :) and as such, it's quite cool already.

Something like it has been done, and it was cooler

[BeeBeard]

Make the array bigger and put Tetris on that thing, kind of like these guys or even these guys.

MIT is lonely for attention ... nobodycares

[Anonymous Coward]

This is the deal: MIT consists of geeks who need to feel they're somehow noticed in the world -- because nobody notices geeks and specially not ones in Boston. So they do bullshit stuff like this 6 x 6 array. Which nobody except slashdotters notices...

Summary lacking something...

[gumpish]

You really, I mean, you really couldn't just say how big this "giant" display is?

Take some notice.

[nazera]

Being a crontrols system desiger, I hope some of the goofs of industry look at stuff like this. I am constantly yelling at my vendors that I don't need a super screwed up version of RS232/485/422 etc to network sensors around a machine......binary and ASCII protocols WORK GREAT for stuff like this. KISS (Keep it Simple and Stupid). A few micros some twisted pairs and your basic switcher......bingo big network of fun.....if you need some more bandwidth, throw Ethernet at it. I've been saying this for over 10 years and still all the big players want to sell you a "Field Bus". I hope some of the MIT guys move in with the big guys...and slap some sense into them.....rant off.

Re:Take some notice.

[maxume]

Good luck. The problem with problems is that they often get 'solved' by someone who thinks it is interesting, while the guy who has the right solution never even knew there was a problem because it seemed so obvious to him.

Re:Take some notice.

[CPMO]

It's exactly the other way around. The dude who thinks the problem is uninteresting thinks his first idea is right because he never thinks beyond that first idea. When things screw up later (imagine the system growing to 100+ sensors, each with their own different binary protocol) the excuse is that noone knew any better at the time. The dude who finds the stuff interesting figured out all these problems long before the project even started because he enjoys figuring out that sort of thing. But he can *never* point that out otherwise he will be labelled teh smug.

Re:Take some notice.

[maxume]

It's at least debatable. For example:

http://hardware.slashdot.org/comments.pl?sid=20192 5&cid=16528159

Which is the better solution? The first guy thinks the problem is interesting.

Circuit design error

[Flying pig]

The diagram shows a simple, basic mistake in circuit design. The Vcc of the microcontroller should not ever be directly connected to the Vcc of the power bus. Adding extra capacitance to the supply is not smart, it is quite unnecessary.

The microcontroller should have a separate supply, and as the consumption of the PIC is so low this could be derived simply by passing the LED supply through a small low voltage drop diode (Schottky diode) and preferably a suitable inductor, and then decoupling it with electrolytic and ceramic capacitors (say 1000uF and 100nF) in parallel as close to the Vcc pin as possible. With this arrangement, the LED Vcc can even momentarily drop to zero and the microcontroller will just keep running.

(In fact, if you are thinking of doing this from scratch, you do not need an expensive supply at all. Rectify the output of a transformer directly to provide pulsating DC (100Hz Europe, 120Hz US.) This is the LED bus. You can do that with a 35A 50V bridge rectifier bolted to a nice big alumin(i)um strip. Then pass the output through a diode, a suitable resistor, and stabilise it with a 5.1V Zener. Assuming a peak of about 8V from your transformer, a 1A Schottky, a 10 ohm 3W wirewound resistor and a 5W 5.1V Zener will do just fine, with maybe a 1000uF electrolytic and a 100nF ceramic to stabilise the voltage at the PIC and provide enough surge capacity to drive the MOSFET gates. That way, you avoid the major disadvantage of switching power supplies, which is that they do not like rapidly varying loads.

Oh, another thing. Do not put a resistor between the PIC and the MOSFET gate. Use a driver chip to translate the current levels. Cheap insurance.

Re:Circuit design error

[Anonymous Coward]

Pray tell - how did you become the leading authority in nerd?

Seriously - you seem to know your stuff. Can I subscribe to your news letter?

Re:Circuit design error

[Anonymous Coward]

I agree with your ideas, but I have some questions.

> Oh, another thing. Do not put a resistor between the PIC and the MOSFET gate. Use a driver chip to translate the current levels. Cheap insurance.

Wouldn't a driver chip be used to translate voltage levels? What's this about current? What does it insure against, the mosfet's gate breaking down or some such thing?

Re:Circuit design error

[dheera]

Thanks for the suggestions. The PIC should actually be able to drive the MOSFET, it's just that there ends up being some small amount of ringing, which then [in some way that I didn't bother to analyze] caused the entire thing to hang. Adding the resistors killed that and made it work especially for cases where a large fraction of the entire array is suddenly turned on. But yeah, redoing it with better power supplies and power circuitry would definitely be something to do when we get time. At the time it was built we were trying to finish as quickly as possible and used ATX power supplies which are essentially free at MIT (you find them lying around in dumped computers everywhere).

Re:Circuit design error

[dpaton.net]

Oh, another thing. Do not put a resistor between the PIC and the MOSFET gate. Use a driver chip to translate the current levels. Cheap insurance.
You're kidding right?

A resistor for gate isolation is just fine, especially for a low side FET drive. A driver chip would cost as much as the FETs, and is overkill to the extreme. In a perfect world, where money and time are infinite for design, it's easy to make anything better. For something like this, a little realism is in order.

My $0.02 on the design:

I've done something similar as a proof of concept for a customer...256 RGB LEDs (50mA/color, ~38A at full bright/full white) with 64 custom processors controlled by a big Atmel. It ran off a standard 600W ATX supply, and it worked just fine, no voltage dropouts at all. I don't think the ATX supply itself was the problem, rather the layout of the circuit. A normal ATX supply has rather good transient reacitve capabilities. Using a single power supply for an entire floor is likely the culprit. It looks like the run on each floor was about 60', and I highly doubt that he used the right sized wire for that run (25A @ 60'-> #8). The accumulated coltage drop would be pretty extreme, making the PICs low voltage brownout inevitable. Combine that with an improper power supply arangement at each processor location and bam, crashes. The 6600uF caps are a band-aid, I agree. A fat wire feeding the high sides of the LEDs, and a secondary wire feeding the PICs would be my choice. Yes, they can safely be tied together, but ONLY AT THE SOURCE. That long run of wire will be all the isolation they need. Standard long distance bypassing at the PICs will keep them happy (10uF/1uF/0.1uF) and a nice fat ground return keeps it all under control. There were a few mistakes, but by no means is it fatally flawed.

Re:Circuit design error

[tuxicle]

I'm guessing without the gate resistors, the rise time of the load current was high enough to cause the voltage to sag at the load (inductance of the supply wiring), making your PICs brown-out. You should ideally have a separate wire carrying the supply voltage for the PICs from the ATX supply. This way, load transients won't cause the PIC to brown out. Perhaps a ferrite on the load wire would help.

Re:Circuit design error

[Anonymous Coward]

Using a single power supply for an entire floor is likely the culprit. It looks like the run on each floor was about 60', and I highly doubt that he used the right sized wire for that run (25A @ 60'-> #8).

I think your distance scale is off by about a factor of two. It's really hard to tell from the nighttime pictures, but this dorm's windows are quite small. I think they're about 2' on each side and spaced 1' apart.

View picture here.

So building on what you said, I suppose... 25A @ 30' -> #11 ?

OOO man I partially understood that

[technoextreme]

Rectify the output of a transformer directly to provide pulsating DC (100Hz Europe, 120Hz US.) This is the LED bus.

Now why are you powering the LEDs with the pulsating DC? I know no one is going to notice the flashing because the frequency is too fast. Im a engineering student who only just recently figured out how a walwart works and why its so heavy.

Re:OOO man I partially understood that

[Anonymous Coward]

This is what's wrong with universities today. An engineering student should have known that before even considering going into engineering. Now you have mouth-breathers barely able to light a LED called "engineers". Oh well, anyone who thinks schools are anything but money gold-mines is a fool anyways. They'll accept a dried earthworm as long as the money flows in.

Re:OOO man I partially understood that

[Com2Kid]

I am CS, but I like LEDs, so here is what I know about pulsing them...

LEDs are pulsed for a variety of reasons. Altering brightness is one of them, it is simple to vary the brightness of an LED by pulsing it at different frequencies.

Heat is an other one, if an LED is being over driven, pulsing it can help lengthen the LEDs life span.

Pulsing also reduces power consumption (only an issue if running from batteries really...)

That's nothing compared to the Cubatron

[neuro.slug]

The Big Round Cubatron is a much bigger, much cooler DIY LED display. It was the cool thing at this year's Burning Man.

Videos here, here, here, ...well, you get the idea.

Nobody asked you!

[Anonymous Coward]

Comic book guy.

another example

[Anonymous Coward]

probably one of the largest and oldest "on building" light displays:
The SKF building in Schweinfurt, Germany. http://mpics.teamone.de/cgi-bin/index.cgi?sort=1&m enu=skfvwg#IMG_8603

Why is this a story?

[Bender_]

Sorry, I dont see why this is a story. The technical difficulty of this is something like "my first microcontroller project" from "toying with electronics 101". The implementation is not even that interesting. (Multiplexing anyone?). The novelty is almost zero (giant LED display.. uhhh). Yes, it is at this geek university, but that is the only real point about this story i can see.

Re:Why is this a story?

[randcv]

It's not even breaking news, this was on hackaday weeks ago. This site needs some serious quality control before it loses its entire fanbase. If I want shitty news, I'll read US Weekly.

Re:Why is this a story?

[Anonymous Coward]

Agreed. Compared to the complexity and geekiness of other notorious MIT hacks (http://hacks.mit.edu/) this is nothing.

Delft University of Technology was first

[Thijs van As]

In 1995, Electrical Engineering students of Delft University of Technology did this, with playing Tetris on their 100m high building.
Link: http://www.etv.tudelft.nl/vereeniging/archief/lust rum/90/english.html

In 2001, they used their building as a big SMS display.
Link: http://www.etv.tudelft.nl/vereeniging/archief/lust rum/95/english.php

In 2006, a huge 8x4x2m LED MatriXX was created.
Link: http://www.etv.tudelft.nl/vereeniging/commissies/e lco/matrixx/

Re:Delft University of Technology was first

[belg4mit]

Sorry, no. Thank you for playing.

Those just happen to be the incidents that someone got photographs of,
there have been many more, including Tetris.

the code

[Anonymous Coward]

#include [16F877A.h]
#device adc=8
#use delay(clock=10000000)
#use rs232(BAUD=9600,XMIT=PIN_C6,RCV=PIN_C7,ERRORS)
#fuses WDT,HS, NOPUT, NOPROTECT, NODEBUG, BROWNOUT, NOLVP, NOCPD, NOWRT

#define address 0 // set this to the address of the floor's controller board

void main() {
    int i=1,a,b,d,e;
    char r,a0,c0,c1,c2;
      setup_adc_ports(NO_ANALOGS);
      setup_adc(ADC_OFF);
      setup_psp(PSP_DISABLED);
      setup_counters(RTCC_INTERNAL,RTCC_DIV_1);
      setup_timer_1(T1_DISABLED);
      setup_timer_2(T2_DISABLED,0,1);
      setup_comparator(NC_NC_NC_NC);
      setup_vref(FALSE);
      setup_wdt(WDT_2304MS);
      r=getc(); // initialize ports a,b,d,e to all outputs and zeros
      output_a(0);
      output_b(0);
      output_d(0);
      output_e(0);
    while(1) {
        r=getc(); // wait for and get a character from RS232 bus
        if(r==0xFE) { // start byte received
            restart_wdt();
            a0=getc(); // get address byte
            c2=getc(); // get data
            c1=getc(); // get data
            c0=getc(); // get data
            if(a0==address) { // yes, the packet is for us, we should pay attention // convert the incoming pixel data into the correct pins that are used // on the 16F877A in this particular setup
                b=(c0&0b00000011)|((c0&0b00111100)>5);
                output_e(e);
            }
        }
    }
}

Tetris

[SnoopJeDi]

It's not even large enough to play large-building tetris on, but I still think it's really cool.

OT: I have an interview with an MIT Education Counselor (EC) for early action this Monday. Between this and the recent protein gel discovery, I should have a lot to talk about with him. Neat.

Re:Tetris

[dheera]

in case i didn't mention it anywhere on the site, the pure reason why it's limited to 6x6 was the fact that it's the largest continuous available public space on the face of the building. if you go left, there's nothing, to the right, the windows stop being regular, and above/below are student rooms that we don't want to bother. we would have definitely liked to build a bigger one, though, if we could.

Re:Tetris

[SnoopJeDi]

Yeah, I did see that on the site. The fitness room is the best spot for contiguous windows available, and 6x6 is the absolute best.

Not to mention that 6x6 works just fine for displaying text, as you guys are doing. More LEDs would just mean more money and more potential trouble spots, anyway. Good stuff all the same.

Quite true.

[Anonymous Coward]

I really expected this to be cool since it was on the front page of slashdot and it's from MIT. I was sure I was missing something, but no, it's just a very low tech boring stupid dorky thing. I wouldn't even call it a hack really. I have a light in the front window of my house, does that mean I have a giant 1x1 pixel display?

There's a guy out there with thousands of dollars of Christmas lights hooked up to his computer and synced to music he broadcasts over FM as you drive by his house. If you tell me some dudes at MIT built a GIANT LED display, well, then that mutha better damn well be friggin' huge. Not 2 scrolling letters in a couple windows in the corner of a building. With the dough they are spending to go to MIT they should be pissed that's all the better they could do, some smarter than your average bear 5th graders could pull that off.

Normally I hate it when people complain about stories not being worthy of Slashdot, but this story and some blog dude buys a Mac and shares his experience with us? I'm just glad Slashdot is still worth what I'm paying for it, although at this rate it won't be very long until it isn't.

Not do it yourself, but bigger yet

[geekzer]

OK, it was done by pro's and cost a bit more than $150, about $17 million more! But at 12.5 million LED's I think the Fremont Street Viva Vision is Las Vegas wins the "biggest" contest. http://www.vegasexperience.com/viva.cfm To provide some scale on the photos and minivid clip, the peak of the ceiling is at least 6 stories above you and the small segment you see is just a fraction of the 1,500+ feet long display. Oh, and from the looks of those photoshop-ed pictures, I wouldn't be surprised if this was just yet another MIT "Prank"....

Driver chip costs

[Flying pig]

For information, an AHC244 (8 way driver) with a +/-25mA output on each driven line, easily capable of switching 5V drive MOSFETS up to several amps, costs all of $0.90US in one off. I consider that cheap insurance. But then in my formative years, before mobile phones and readily available Internet, I had to design stuff for installation in remote sites. And to make sure I got the point, I had to do some of the fixing. When you have traveled from the UK to the US to do a repair under warranty, and found the problem was a failed power transistor due to somebody not bothering to buffer the driver, you get the point of cheap insurance.

Your other points, though, about adequate power supply cabling and decoupling, are spot on.

Re:Driver chip costs

[dpaton.net]

I've spent more than my fair share of time in the field doing repairs due to blown transistors, failed drivers, and the rest. Every single failure (in an outdoor, harsh environment, intrinsically safe, and heavily abused embedded system for agricultire, which I'm using as an example here) was the result of amazing abuse of the output devices. Load dump spikes hundreds of times over the design limits, connecting 120VAC to a terminal marked 12VDC, lightning (which it survived with only one blown transistor out of thousands of parts), etc. Each and every time, the failures could have been prevented with proper protection of the I/O terminals and a little common sense on the part of the operator.

For an application like this, where the only connections to the outside world are power and network, it's a pretty safe bet that the LEDs won't fail and kill the drivers. LEDs, especially the high power ones, fail open in a blinding majority of cases. A failed open LED will present no killing load to the low side switch, and no killing load to the uC. Even if it failed shorted, the odds that it would take out both the FET and the uC pin, with a 1K gate resistor, are damn small. If I was designing a system like this for mass production in a harsh environment and it needed five nines availablity, then yes, drivers would be appropriate, along with load monitoring, optoisolation from the network, and a few other things. For a one off 6x6 hack, or even for a low buck small market (1-10k units) project, the simple limiting resistor is fine. I'd be all about a driver if he'd used BJTs instead of the FETS, or if he was driving really big FETs like I do for motion control and light dimming applications (10s -100s of kW). They make tons of sense there. Take the scope of the project into account...the driver just isn't needed here. And the +/-25mA current on the 74AC244 is the clamp current, where the chip says "oh shit" and stops the party. The operating current is a much mroe reasonable +/-8mA, with headroom for odd loads and capacitive situations, and with a 50mA package limit. It'd work fine, but like I said, in this particular application, it's not required. That's my only contention.

RGB

[tygerstripes]

So, your resolution is hugely limited... try RGB. Works for TV. Tellys have a pathetic resolution, but a decent colour range, so they can produce much more convincing images than would be expected (this is why B&W TV always looks shoddier, even with modern footage).

Can't imagine it'd be that hard or expensive to introduce some colour to the scheme.