Free Project - 245 LED Display

[fazan83]

I realize that with my time here thus far I have offered little in terms technical assistance, PIC Basic snippets and so on.

So here's a nice BIG fish for everyone to cut their teeth on. A 245 LED, PC-programmable moving message display. Near-final cut, early last year the project was prototyped on two large PCBs and performed quite well. It's mandatory that high-intensity LEDs are used because the duty cycle is only around 2.8% for each column in the multiplex scheme. (Do NOT recommend expanding the display with more columns, the design is at its limits as is)

The component count is quite immense. This includes a 16f628, 24LC256 EEPROM, Max RS232, Decade Counters - 4017 variety, tonne of common passives, it'll take a couple of solid days work to put together. I can't offer the PCB layout sorry.

The zip file download includes schematics, micro controller source and Windows-based source written in Visual Basic 5.0, plus compiled executable. You will need the Virtual machine runtime DLL for the executable. This can be either msvbvm50.dll or msvbvm60.dll which are both freely obtainable.

Best Regards,
Trent Jackson

Trent Jackson,
I am really interested with your project but can you please post the code here?
I want to see the code and try to understand it.
That is the best way for me to understanding your design.

If cannot then fine.


Thanks in advance.

Ops sorry I just found the code here.

Sorry for not looking the file properly.
I will try this and ask you if I have any question.

Thanks

[T.Jackson]

Everything is in the d/l - if you have any queries then just post them here.

[Dan Cata]

Dear Trent, i have recently installed Win XP on my comp and copyed MSCOMM32.OCX in sys32 (VB not installed) ; the aplication runs but when i press "program messege to eeprom" button, i get an Communications error "Port already in use or doesn't exist ; Chose a different port " but the com1 is free; what do i do?

[T.Jackson]

Apart from suggesting that you try another comm port, it's hard-to-say because everything works fine on my end. I have Win XP with service pack 2. If there was a problem MSCOMM32.OCX, the program wouldn't run at all. So you can rule that out.

[magu]

I have build my led matrix from the start to finish. and i have some problems... I finaly programmmeed the PIC and when i connect the 5V and the 12V and the Serial Port, and when i bush the button for program LED it doesen`t stay ON (lighting).I start the VB program to sent EEPROM the informations but when finished nothing happens. I have a link with the sheme that i construct... i hope you can help me... THX.. I will wait for your answer.

http://www.zamfirelu.org/lm.jpg

[precision]

What is this ?
Why you mount all 14 capacitor in one place ? and there are no capacitor between PIC's VCC and GND.


.

[T.Jackson]

I'm getting emails left right & center from people telling me about their problems with this thing. It's not a simple project - in my opinion, it requires the constructor to have some sort of formal background with electronics. If you build it, you've gotta be prepared to fault find your mistakes, because you will make them, there's a lot of wires & parts and a whole range of silly little errors that could occur.

By the way, I noticed on your photograph of the board that all the 0.1uf decoupling caps are banked up together ??? They actually need to be placed as close as possible to the power connections of each chip. (That's why there's so many of them, one for each chip) Knowing this sort of thing is relatively basic electronics and if you aren't aware of simple things like this then I highly discourage you from building it. Sorry - the truth hurts.

[skimask]

Knowing this sort of thing is relatively basic electronics and if you aren't aware of simple things like this then I highly discourage you from building it. Sorry - the truth hurts.

Abso-tively Poso-lutely....the sequence should be: One blinky LED, then 245...

But, we all know, it usually starts the other way around...

245 non-blinky LEDs, then back to one non-blinky LED, then on to one blinky LED, then, and only then, do you get 245 blinky LEDs...(well, maybe a few extra steps in between)...