Like-a-pro soccer display?

I think I need a stroke of our Ben-genius!

yep, this is the 500 US$ unit I was referring to

Hi Carlo,

If you use 3 LEDs per segment and 7 segment digits you need 42 red LEDs and 42 green LEDs.

These cost about $15 - $20 / 100.

You could use 4 BCD switches to control the digits at about $7 per switch.

You could use 4 BDC to 7-segment decoder chips to drive each digit at about $1 each.

You also need a resistor on each segment, a battery and a power switch.

From there you need to decide how to connect everything (trade-off between labor and cost)

Doug

"You could use 4 BCD switches to control the digits at about $7 per switch."

Yes, that would work.

One rotary encoder switch would be cheaper. Push to select the digit, turn to change the digit. 4 inputs required. <$3.

Left-right (select digit) and up-down (change value) is another option.

A super-cheap bluetooth serial module (~$2) is an option. Serial into the Arduino and control it from your smartphone. No buttons, easy UI.

For daylight visibility across a football field you probably do need high power LEDs @ >>50mA. Bright ones will be 350 - 700 mA.

Not sure that you will get BCD-7 seg decoders that will drive that sort of current.

4 x 7 matrix is fewer i/o lines (11) than 4 x 4 BCD (16).

Arduino Nano should be enough. You can get those <$5.

The cheapest way to get a lot of bright LEDs connected up is to use some LED strip. Shop around and you can get some bargains. Cut the strip into lengths to form the segments. Stick them to a board and wire them up. They typically just need 12 on the end terminals. Series resistors are included.

Get 60 LED/m. If you want denser spacing put two or more strips next to each other to form a segment.

Mechanical could be the way to go. Manual slides or flaps to set the state of each segment. Maybe some LED just to illuminate.

Something like this!

Football Substitute Board | Football Resources For Coaches, Teams And Players - Forsport

or this

Substitute Board | Football Substitution Boards | Soccer Accessories and Equipment

Manual segments. Black one side coloured the other. Super cheap!

What? Too low-tech for you?

pigraham this is the system (more or less) that the team uses today. My idea is to provide them with something more similar to the professional teams. I'm happy because I'm getting a number of suggestions and ideas from the Community. And Easter may bring some more.

What price do you have in mind?

the budget for components I have in mind is around 50 Euro (70 US$), excluding Arduino Uno

I really appreciate your intention about making this project... If still you are facing some problem then update here.. May be we can help you... Any way All the best if u r still working on this project... or.. Congratulations if u have done with this.