in ours 400
but that is for a 40cm high clock that can be seen with ~2000W worth of lights on it.

you could use our board to drive normal 7 segment displays, (or the jumbo ones) using darlington driver chips, I think up to 1A per segment at up to 40 volts. Thats probably a better solution to what you want to do. That way you can have a number of displays around the place.

We got our LED's off ebay, I think the seller was chiwing?
They have come down in price quite dramatically, 500 white LED's for $25 with free shipping.
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http://stores.shop.ebay.com.au/onlinebigsale__W0QQ_sacatZonlinebigsaleQ5fQ5fW0Q51Q51Q5farmrsQ5A1QQ_sidZ229907426?_nkw=LED&submit=Search

They have 2000 Blue, Red, White or Green LEDs for like $70. That is crazy. I could get 2000 but I dunno whether I can handle soldering more than a few hundred LEDs. May go a little crazy. Could make a pretty epic display with 2000 though, might be a little power hungry.

Think I might try and setup display with serial input so it can be driven from a PC.
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Steven Martin
Twisted Constructions
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I went down that line but making it independent makes it simpler to use.
IE anybody can use it ;->
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Mechanical engineers build weapons, civil engineers build targets

I was gunna make it default to stand alone operation, but allow time to be set and managed via serial as well. Its really just a software issue. Soldering all the damn LEDs is going to be the biggest task.
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Steven Martin
Twisted Constructions
http://www.botbitz.com

yeah thats a good plan.
Like I said for a beetle arena 7 segment displays are the easy way to do it.

the easy way to do the display is put the LED's through a board (tight press fit) then just solder the legs togther into strings. 4 led's for 12v with a resistor as I recall.
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Mechanical engineers build weapons, civil engineers build targets

Sparkfun have relatively cheap 7" 7-Seg displays.
http://www.sparkfun.com/commerce/product_info.php?products_id=8530
EvilMadScience have 12" version too
http://evilmadscience.com/partsmenu/107-sevensegment
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See this would be a perfect time to make use of my CNC table if it had survived the move. Tossing up whether to get 500 or just do 2000 for shits.

Also you reckon blue is best?
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Wow 12inch 7 segment displays that is massive.
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Steven Martin
Twisted Constructions
http://www.botbitz.com

we got blue cos at the time it was cool
green will be "brightest"
white would probably be unusual now, but more likely to get washed out
sparkfun has a giant gps wall clock that was what we based making the digits off.

if you want CnC stuff we can do that
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Mechanical engineers build weapons, civil engineers build targets

Nah it should be right. Would just be an easier way to drill 500 holes. But I am sure I can manage. I built an air hockey table back in primary school I think that had something like 20,000s 1mm holes in it. So 500 5mm holes isn't too bad.

I am leaning towards blue. Red is a bit plain and I don't think green really catches peoples attention.
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Steven Martin
Twisted Constructions
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Have a look at my post in the car thread about my Nixie-Tacho.

You could use the I2C bus controlled Smart-Sockets to run either Nixies (for a really funky display ), Numitrons or plain 'ol LED 7-Segment displays with a 2-wire (+power) Bus, of course you need a Micro to run it, but if you've got one anyway, a few of the cheap smart-sockets will save you a bunch of wiring.
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The Nixies would be awesome but not sure whether they would be big enough or affordable. I am having a bit of trouble finding the I2C bus board on the website linked from you big car post. I found one @ farnell but its $18 for one IC. In and buy the time I make a board and stuff I might as well program my own $2 AVR.

Can you give me a bit better idea where I should be looking.

Thanks

Steve
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Steven Martin
Twisted Constructions
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Oops, sorry, the SmartSockets are 5v-serial (not RS232 volt levels) controlled, not I2C bus controlled. which is even easier to drive than I2C.

You can find them here - http://www.tayloredge.com/storefront/1386_B7971SmartSocket/index.html

They are normally used to drive the large B7971 alphanumeric 14-segment nixie tubes, but you can easily drive any 14-segment starburst display with them. Quite a few people have used them to run LED or VFD displays.. http://youtube.com/results?search_query=smartsockets&search=Search

If you arent going to use the big B7971 tubes (about $60 each, so maybe not affordable), then you can just leave out the HV transistors and resistors off the smartsockets boards when driving low volt displays, or just use the smart-sockets micro (buy programmed, or download the code and program your own, its free) and make your own board.

The Micros are cheap and mean you can drive as any displays as you like from your controller with a single daisy-chained serial line.. more info and example of use of alternative displays here. http://www.tayloredge.com/reference/Circuits/1386SmartSocket/index.html

If you just want numeric display capability without alphanumerics, then the Smart-Nixies (as opposed to the Smart-Sockets) are the I2C driven model, and can run high voltage numeric nixies, or be run in "Numitron" (7-Segment) mode to drive any ordinary 7-seg displays from an I2C bus and are quite cheap - http://www.tayloredge.com/storefront/SmartNixie/index.html
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Had a bit of a look around the edge yesterday and we are still trying to work out where exactly to put the pits. I was thinking downstairs as they are fairly protective of the floor however daniel brought up the point of everyone running two and from fights which would be a rather big issue.

Atm we are still trying to work out exactly what we are doing with the space. Hopefully we will be able to have access to a floor plan this week and can try and work that out. There is a few spots upstairs but what we are allowed to do and how to keep the public separate is something we are working on.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

For the displays I am thinking that just running the Sparkfun 6.5" 7 seg displays might be the way to go. By the time you add in the electronics should be doable for around $100. I would like to run a wifi module on it if possible as well to allow remote triggering from software of external remote, but we will see about that.

If anyone would like to build a massive LED one that would be great but I just dont have the time.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com