I have recently aquired a 6 foot long Led sign, the leds are arranged 7 high and 28 long x 4 (4 boards joined together) this totals 784 leds (red) Working The sign is made up of 3 parts, a PSU - gives 13V dc for the control board, 5Vdc for the LED board. A LED board, made up of four individual bits (what a six foot pcb..) The display bit is made up of : 4x 74LS244N (one for each board) 74LS164N, ULN 2803A chips (one for every 8 columns) A few TIP115 transistors (randomly hooked onto some leds...) A few 7445N chips. Lastly the motherboard, lots of stuff here. Let me begin by saying when i got the sign, it came up with 'logical garbage' like lots of symbols, bot of phones and other logical signage stuff.. After cleaning the years buildup (made in about 1990) of much off the tracks and removing the corrosive battery (3v memory retaining batt) the sign now just lights up all the leds (some fainter than others - lots of power there) The main things i need to do though is figure out how to program it - this is where i need your help - and replacing the battery / repairing the corroded away tracks. The main board is made up of: 1x TMS9901NL-95 microcontroller (texas instruments) (main control) - wired to display area.. 1x TMS9995NL microcontroller (texas instruments) (main control) - wired to eeproms mainly...3x TMS2532JL EProms (character / firmware) 6x 61162 memory chips - 1k data - this is what the battery was for. a L7805CV - 5 volt stabaliser i think (on a heatsink) some misc resistors / caps diodes... 12mhz crystal. 8x small ic's - numbers: 1x MC1489N - TTL-RS232 converter - pin 4 connected to one of the pins of the datalink wire 2x PC74HC138P (philips) 1x 74LS00N 1x PC74HC00) (philips) 1x TMS9902ANL (texas instruments) 1x 7400N 1x 74LS04N As i said earlier, the main thing is getting this thing programmed, i guess the 3 wires used for programming (as there is only 3, they go to: Pin1: one side of a ceramic cap, of which trhe other side goes to pin one of one of the 9901 Microcontrollers. Pin2: Goes to +13V DC Pin 3: goes to pin 4 of the MC1489N I need help here, any info you can provide on this would be greatly appreciated. Ant BTW, no name on it, except IGG, who made the boards, not the sign but are trying to help. Almost forgot, Pics here (bit blurey and crappish , feel free to ask for more of places...
I've used an older sign before. It had an external keyboard used for programming. Had a small cable from it that was detatched after use, most probably serial. The hard part would be figuring out the comm protocal. If you could find that, a serial port , and the right program would fit the bill i'd imagine.
although you could deff reprogram this yourself as is, i would suggest that you not. technology has changed so greatly sence the days of UV erase prossesers and 1k RAM chips. nowadays you can get a 32io line flash PIC and a 16meg eeprom for less then a buck each. i would say that your best bet is to keep the line drivers, but scrap all of the control circutry and build your own. it would be simpiler, faster+better, and cooler if you could desiged something working around a Basic Stamp or a PIC. it would be _some_ codeing, but in basic or C it wouldent take long. and you could add features that the original desigers could only dream of. btw--figureing out what all that stuff does could take years... good luck
Xiachunyi, The EProms hold the firmware (charactersets and other stuff) , since they are not EEProms (they require a UV light to erase them) it would make it impecably hard to reprogram the sign. Manitowic999, you are 100% correct, however, these signs normally can connect either to a mini keyboard or to a pc, i beleave the PC is probably an easier option. Edit: The Shadow, you somehow posted at the same time as i posted this, but that is my last option as i am not looking forward to that much since i really have no idea of how to do it... (yet) I mean there are only 20 interface wires... I will also accept ideas on how to do that since it is a very viable propasition...
yeah i could explain it to you.... i would leave the line drivers + octal 3state buffers in place, you can use them. but you may have to re-build the bus. if your intrested, let me know and we can go thugh it step by step
i am interested: MSN : bigup2bigal@ntlworld.com You mean just replace the whole mainboard, leaving the daisplay intect. If you name the ideal components, that would be a start since i dont really know what is abailable... i have a pic programmer and some PIC16F84s and other stuff...
JUST AN IDEA! how mutch would it cost to ship it to Norway?.. send it to MEEEE! Well back to reality.. good luck!
Update: From the makers of the PCB: It uses a keyboard only, it does not plug into a computer It is called an "Orion News Scanner" I am making up a schematic for the display so maby people can think up some ideas...
ok, i have finnished the display PCB sketch. It is in CIRCAD98 format. Circad 98 can be downloaded for free here (4mb): http://www.holophase.com/dleval.htm Download the PCB here (19kb): http://www.hellzbellz.net/screen_dumps/LEDSIGNDISPLAY.zip I thank anyone in advance for any info / ideas or suggestions. I am trying to base this project on this project: http://noisybox.net/electronics/LED_sign/ Thanks
Can you post a schematic in GIF format? I bought an LED message sign off ebay and remade the controller (really pretty darn simple), it was just an issue of identifying the shift registers (2 32-bit UCN5833As) and the pnp row transistors. Any pics would be appreciated. [edit]AHA! saw that you talked about pics in the first post... Good luck trying to program it.. Might be pretty simple to remake the controller.[/edit] [edit2]2 things. 1. Wow that's an old LED sign. I doubt you'll find much programming information. You can take advantage of the shift registers and just pulse that data out if you take the time. 2. Clean your keyboard![/edit2] -special [k]
ok specialk, thanks for your interest and suggestions, i wish to make a new controller, thats the plan, i have been unsuccessful in making the schematic in gif, but through alot of messing about have got it into pdf format. (god bless the PDFMaker printer driver) Downloadable 24/7 HERE (2.4mb) Thanks for the info. It is much appreciated.
Does this help...? Just happen to see this this morning...what are the odds? http://www.microchipc.com/debt_clock.htm It uses an 8ft LED display, but you may get some ideas on how to make yours work. Good luck.
hmmm, bit different though... It has 7 segment leds made up from 5mm leds.. so it can only display numbers.. But i think i will need a MAX232 and a pic in mine, along with a 5v regulator at least. I will start up a schematic if someone can name the ideal pic. BTW: it would be useful to be able to program this then unplug it from PC and let it run if that doesnt increase technicality too much, if it does, dont worry.. Cheers for all the help, and cheers for the link above it helps a bit! uhhh, just noticed i have VB6 studio.... i have NO IDEA where it came from... but hey! edit2: I think i may need a boot loader for this, so i make an "in circuit reprogrammer" so the software i write (shudder) in VB reprograms the PIC via the MAX232 and hey presto! I could even have it so i can optionally maintain an uplink to the pc (when its on) so it can display time from the PC!!! (I plan to mount this thing on the wall outside my room and sell advertising space!) (Anyone who helps gets 1 week free!)
Just to add, i can program these PIC controllers: PIC16F8316 PIC16C554 PIC16CE624 PIC12C509 PIC16CR83 PIC16C556 PIC16CE625 PIC12C509A PIC16C84 PIC16C558 PIC16C710 PIC12C518 PIC16F84 PIC16C61 PIC16C71 PIC12C519 PIC16F84A PIC16C620 PIC16C711 PIC12C671 PIC16CR84 PIC16C620A PIC16C712 PIC12CE673 PIC16F627 PIC16C621 PIC16C716 PIC12C672 PIC16F628 PIC16C621A PIC16C717 PIC12CE674 PIC16CE623 PIC16C622 PIC16C715 PIC12F629 PIC16F818 PIC16C622B PIC16C642 PIC12F675 PIC16F819 PIC12C508A PIC12C508 Would any of them be suitable, since i dont really want to buy another progrmmer..
