Digital Number Displays

Hi.

Welcome to CR4. You'll need to tell us what the display is for. An example might be a temperature display for an oven. Or, a counter that counts people coming into the movie theater when you depress a button (the control), or they break an optical beam. Get the idea?

Hi,

Thank you for your prompt response. This is to display the song numbers for the devotees in a prayer hall to refer from the book. This goes upto four digits. Number display is made of LED assembly with the number height about 12cms. There will be two displays for two language books and will appreciate, if a single control box could dictate to these two displays to show different numbers at any given time.

Please confirm if I got it right...

A person is standing at a place with a control for setting the four digits in a LED Display. The display is about 4 meters away. Whatever number is set from the control is shown in the LED display.

Also please confirm if you want the number to be displayedin english numerals or any other language..

And please elaborate a bit: "There will be two displays for two language books"

Hi,

You are right. Displays will be away from the controller. There will be one controller with two displays for two language books. Displays are in English numerics only -1, 2, 3, 4, 5, 6, 7, 8, 9, 0. Whatever the number set from the controller, maximum 4 digits, is shown on first display and the second setting is down for the second display.

The transmission could be either cordless or with cord. Looking for a simple and low cost system

The simplest way to accomplish what you want is to use a 'BCD to 7 Segment decoder' for each digit of the display. (Do a search for "BCD to 7 segment decoder" online)

For each of the two required displays, Use a 4 digit switch with BCD outputs (1, 2, 4 & 8 for each digit) to feed a BCD to 7 segment decoder ( 4 total decoders per 4 digit display)

Feed the 7 segment output of each decoder directly to its respective digit of a suitable LED display.

Depending on LED power requirements and decoder drive current specs, you might have to amplify the 7 segment decoder output to drive the LED displays.

Hi,

I am happy with this suggestion and I will try this. I will contact you, if I encount problem. Thanks.

You say you have little electronic knowledge, and while what you are attempting is relatively simple, it will lead to a reasonably complicated circuit board. You will have to have some knowledge of binary logic, CMOS chips, Dc power supplies, probably driver chips (for big LEDs) and breadboards. Maybe veroboard. Hmmmm.

My project instinct antenna are slightly piqued, but not much. Too often I have designed extensive circuits and even built same (even had designs in production), only to find someone else had an easier simple method. Of course I still have the joy creating my own beast, but often the poor thing had to be put down

The previous answer about BCD switches and display drivers is the obvious simple answer. You will probably need a Darlington driver in between to drive ultra-large LED displays.

Nowadays I forgo this stuff and would use a PICAXE chip. You can drive the 7-segment displays directly (via a driver) by poling each character at high frequency. You don't need any 7-segment drivers. the 18A, 18M & 18X series chips allow you to connect a keyboard. This could also enable you to use rudimentary text also. As the PICAXE is programmable, you can adapt it to other uses in future (e.g. a dot matrix rolling screen display).

But again this requires some knowledge of basic electronics. And while this is easily in the grasp of a schoolchild, is this what you want to learn?

Google PICAXE and buy a little kit if you want to experiment. I recommend it. I fondly remember using a PIC microcontroller c/w FLASH ROM, breadboard, USB interface, 2 GHz PC, Windows XP, internet software downloads, and a small programme - just to flash an LED on and off. How far we have come to arrive back where we came from

However to get back on track, try a rolling screen display kit:

http://www.apogeekits.com/ad_display_r.htm

Failing that you can cheat and buy the whole cannoli:

http://www.ledssuperbright.com/vr3-car-led-display-sign-p-150

Fiendish these oriental types.

See I told you so. Someone else thought of something simpler:

http://www.budgetlighting.com/ledgo-custom-led-signs.html

These guys are modules 3" wide x 4" tall. Each module is purchased separately and clips together. The number module has a button which counts through 0-9. Easy to wire these to a multi-core cable and run it to a little panel of pushbuttons.

And I haven't even tried.

If you have very little electronics then one of the plug & play options suggested my previous posters.

Del

Hi,

Where could I find your plug and play option. Please advice.

I meant as per #7

Welcome to the insanity.

You stated that you wanted a simple solution for someone with very little electronic knowledge.

I believe that you already have the basics for what you want already.

Collect some old VCR units that have digital displays. You say you need 4 numeric displays. Fine. Remove the display section from two VCRs, and extend the leads for them. Paint over the first three displays of the first one, and mount both displays next to each other so as to show 4 numeric displays. Use the first remote to select the first number using only one number. The three remaining numbers would be set with the second remote.

I know you wanted larger displays. One of the electronic specialists here should explain if the displays can be upgraded to larger ones.

There must be electronics made for this purpose. Stores that call out numbers for customers when they are busy have displays like that. Restaurants also use similar systems for notifying waiters and waitresses when they are needed. Good luck.