# Electronic Scoreboard

#### neilgr

Joined Apr 20, 2016
11
Hi everyone,

I'm interested in building an electronic scoreboard for my sports club. I have a very basic understanding of electronics but zero programming eperience. The design I have in mind is similar to scoreboard in the picture below...

I've read several threads on the topic already, and have found one which I think maybe applicable to this project.

In the thread @elec_mech suggested using the hardware option with CD40110 counters and ULN2004 amplifiers. The only differences will be the number of and type of seven segment displays (will be using led strips instead) and that I plan to control the display wirelessly. I'm thinking the digits will be 12" so each segment will be 6" and I plan on using something like this for the wireless control (obviously with more channels). I understand most of the calculations in the above thread and I think I can modify the schematic/design to suit my design, however I'm having trouble in determining the total current needed and as a result determining a proper and apt power supply.

Any assistance you can lend will be greatly appreciated.

Neil

#### elec_mech

Joined Nov 12, 2008
1,500
Welcome to AAC.

There are a number of ways of making a display, but if you want to avoid programming, the CD40110 works quite well. To determine the current draw, you'll need to know how many LEDs you'll use, how they'll be wired, and their current draw. Let's go through an example using some numbers I'll pull out of the air, i.e., don't use this example as your design without verifying everything.

Most LED strips run from 12VDC. Further, most strips allow you to break them up into groups of three LEDs at a minimum. Let's assume one set of three LED's is in series and pulls 20mA. Let's also assume each strip of three LEDs is about three inches long. We'll also assume you want to use two rows of LEDs per segment (the one you show has three rows per segment).

Therefore, each segment will have four strips of LEDs where each strip needs 12VDC at 20mA each or 80mA total. Each digit has seven segments, so each segment will require 80 x 7 = 560mA. If you're trying to replicate what you pictured above, you'll need 15 digits or 15 x 560 = 8.4A. This is worst case if all the digits were lit and showing the number 8. Therefore, you'd want at least a 12VDC power supply rated for 9A or more. Again, this is an example with some gross assumptions.

Also note that using the CD40110, all digits will be lit. In the display you pictured, the unused disgits are off. If you opt to use the CD40110, the unused digits will display zero. If you're okay with this, you're set. If not, you'll probably want to look at a microcontroller solution. These aren't too bad, it really boils down to what you want to do.

#### Dyslexicbloke

Joined Sep 4, 2010
559
You can actually do that with bucket load of diodes and some wafer switches, 10 position, but to be honest a microprocessor, perhaps an arduino whic comes woth a huge cominity of users and downloadable code, would be quicker and probably easier and cheaper.

I can offer pointers for both if it will help.
Of course so can litterally thousnds of others ...

Dont be intimidated by the programming. you rea not trying to do anything quick or complex so you will be able to find stock code to do much of what you need and use a device that is plug and play with a simple high level development environment.

Al

#### neilgr

Joined Apr 20, 2016
11
Thanks for the replies guys. @Dyslexicbloke I've actually found several projects which can be applicable with the relevant coding but I'm having trouble altering the code to suit my application, that's why I'm thinking about going the hardware route.

@elec_mech ideally I would have liked for the digits to be off when not in use, but that's not a problem. I wasn't really planing on using a two rows for each segment. Do you think one will be sufficient or should I lean towards two? The viewing distance is roughly 120 - 150 ft....since I'm going the route of wireless control, will it affect the design in any way to the design stated in the aforementioned thread?

#### Marley

Joined Apr 4, 2016
353
An interesting project but probably not for a beginner! I think you could tackle the project by breaking it into separate design areas:-
• Design and build the large LED digits.
• Design and build power drivers for the digits.
• Doing the counting with discrete logic (CMOS gates and counters) or a micro-controller. This depends on...
• How are you going to input the scores?
The last one could be just buttons or switches. In which case logic probably OK. Or better - use a laptop or desktop computer. It would be nice to write a simple application in VB or even Python that has a screen display similar to the scoreboard and have the PC upload the numbers to the scoreboard whenever anything changes. Probably by using a serial connection to a micro-controller. Then the scorer sees the same thing as everyone else so no errors.

#### elec_mech

Joined Nov 12, 2008
1,500
Do you think one will be sufficient or should I lean towards two?
With 12" tall digits, one should be good, but this will depend on the characteristics of the LED strips themselves, i.e., light output and viewing angle.

The viewing distance is roughly 120 - 150 ft....since I'm going the route of wireless control, will it affect the design in any way to the design stated in the aforementioned thread?
I'm not quite sure what you're asking here, but a quick search on digit height and viewing distance turns up you'd want a minimum digit height of 4" to see from 150 feet. 12" tall digits should be easily seen at that distance, but again it will depend on the light output (mcd) and viewing angle of the LED strips. I'd suggest making on digit with one strip per segment then testing it out where you'll wish to use this. You also need to think about factors light viewing at dusk/night vs. full on daylight. You'll need brighter LEDs for daylight and dimmer ones for night. If you need to see the display in both conditions, you may need to add a way to switch the resistance to the LEDs to change the brightness.

You'll also need to put a lot of thought into the case design to keep the elements out but keep the electronics cool.

Do you want to recreate the pictured display in your original post exactly? If not, could you tell us what you want to display?
Example:
Score A - 3 digits
Score B - 3 digits
Etc.