running message display

[marsvoltaire]

ei guys, please help me how to build a running message display(LED display) circuit which will be interfaced through a PC.A visual basic(GUI) program shall be used to input the message display and also to control the speed .Also the source code for that program.Tnx

 

[panic mode]

Easy...
Create circuit that can turn on and off bunch of LEDs based on
bit value of the memory location in the controller. Let controller
scroll the memory and make sure the speed depends on value
in another memory location. Create some sort of interface to
the PC and make sure controller and VB program running on
PC can use it to exchange data. To save on I/O count and wiring
try to use multiplexing. If you want to make large display, consider
using multiple LEDs to form one pixel. There are some prewired
LED clusters such as 5x7 etc. Make sure to take care of power
requirement for the unit. If the unit is going to be in non-accessible
location, plan on wireless or at least modem connection.

 

[kinjalgp]

Similar project was published in "Elektor Electronics" in recent issue I think Oct-Nov 2003. Check it out @ www.elektor-electronics.co.uk

 

[laroche73]

moving display hardware

This project site has some detailed info on using a PIC16F84 to control a 5x7 array of LEDs. Includes schematics/code/etc. Experiment #12 deals with moving/scrolling displays.

 

[marsvoltaire]

Easy...
Create circuit that can turn on and off bunch of LEDs based on
bit value of the memory location in the controller. Let controller
scroll the memory and make sure the speed depends on value
in another memory location. Create some sort of interface to
the PC and make sure controller and VB program running on
PC can use it to exchange data. To save on I/O count and wiring
try to use multiplexing. If you want to make large display, consider
using multiple LEDs to form one pixel. There are some prewired
LED clusters such as 5x7 etc. Make sure to take care of power
requirement for the unit. If the unit is going to be in non-accessible
location, plan on wireless or at least modem connection.

i really dont know how to do that...Could you please give me the exact schematic diagram of the circuit and also the source code of the program if you dont mind...Pls help me do this project...I will appreciate all the help that you will give...Thanks a lot.

 

[crust]

The exact circuit, software, and board layout were given in an aforementioned link. Further, it is doubtful somebody is going to do all that work for your project.

The best place to start would be to learn how to multiplex a 5x7 led array. The trick to many of those displays is that they only have one row of leds on at any one time. They cycle through the rows so fast, that the persistence of human vision cannot tell the difference. After you have figured that out, it would be clear how to control 10x7 or even 20x7 led arrays. Then you need a way to control which lights go on and off. That is easily handled in a simple microcontroller.

 

[Johnson777717]

The schematic and source code is in November 2003, under Downloads at the Elektor website mentioned before. This should be all that you need...