Football Score board component list help.

Hi Everyone,

I have decided this winter I am going to make a 8’ electronic scoreboard for my kids football team. I have seen some different examples on how the 7 segment displays work but I am confused as how they are wired all together and how many wires go back to the arduino.

I have a spare Mega that I will be using for this project.

Here is the parts list that I am planing to use.

12 Volt Power supply
Mega 2560 V3
Roll of Cat 5 cable for wiring

LED Type: 5050 SMD 12v

I bought the RGB version because I thought I could use just one color for Scores, and Quarter. and I was thinking that when the clock changes to the last minute go from white to red for the seconds count down.

9 leds per segment (total of 63 segments)
Time 4 *7 segment
Home Team 2 * 7 segment
Away Team 2 * 7 Segment
Quarter 1 * 7 segment

63 N-Channel Power MOSFET transistors + 14 more for the time color change (but I am not sure which ones)

now I am not sure which shift register (or if that’s the proper name) I should be using and how to have all them connected.

is it the TPIC6B595 and would I use one for every seven segment digit? and can have them daisy chained together, and what is the max amount of them I can use together.

Any help would be greatly appreciated.

Jasit

Generally I think you have ordered enough components, but you don't need a power shift register if you are using FET's to drive the LEDs

i.e the TPIC6B595 can drive a small number of LED's on its own (spec was for 150mA per output, but I doubt that would be enough if you wanted big digits using a lot of LEDs

Take a look at

and

The 74HC595 is best as it can latch the outputs (store their state) - which would reduce flickering on the display. (not sure how much of an issue flicker would really be, but I'd still use the 595)

Hi,

Thanks for the info, so I am assuming I will need 11 74HC595, and use one chip per 7 segment display. (main clock will have an additional two so I can do the last minute count down in a different color.

Thanks,

Time to order the parts so I can start testing.

There is a chip on the market( OF cannot recall the part #, sorry) which will control 8 x 8 LED matrix individually ( latched outputs and some limited intensity control ) using serial data
It may simplify you hardware.
It was mentioned on few posts here.
If interested I'll try to locate the part #.

I googled control 8 x 8 LED matrix

I found it the Max7219 they show it controlling 64 led's with one chip, that's awesome. thanks, I think I might even have one with the kit I bought.

Thanks so much, I will check it out.

jasit

That is the beast. And if you do not have one I have some I can put in mail for you. Question is where are they.
They are fun to program.

MAX7219 will need lots of components to drive high voltage & current.
Other versions of TPIC6x595 can drive higher currents, up to 350mA.
TPIC6595 for instance can sink 250mA continuous from a 45V source.
If you can wire the LEDs in series so you have say 15-20 LEDs in series all sharing 20mA from 45V source, and make each segment from say 4 strings (arranged physically as 2 long by 2 wide, so it looks like 2x40), then each segment needs only 80mA and TPIC6B595 would be fine, use 1 for each digit.
I offer a board that can sink current for up to 12 digits; the 45V+ would connect to the LED +and the 45V Gnd would connect to the board Gnd. It has a '328P chip for arduino functionality. An offboard FTDI Basic or equivalent is plugged on for serial programming. IO pins let you connect buttons, an RTC module, etc.
Cross Roads Electronics scroll down about 2/3 of the way

jasit:
I googled control 8 x 8 LED matrix

I found it the Max7219 they show it controlling 64 led's with one chip, that's awesome. thanks, I think I might even have one with the kit I bought.

Thanks so much, I will check it out.

jasit

You can control 64 leds/segments (8x8) with just 16 pins, but it comes with another cost as well.

While displaying, only 8 leds (1 row/column/number) max will be on at the same time. By displaying rows/columns/numbers fast enough after each other it seems... like all 64 leds can be on at the same time, but that's not the case.
It's our Persistence of vision that makes us believe they're lit constantly.

If you would use a chip/solution like this, individual segments will only be lit 1/8 of the time. As a result your scoreboard will be far less visible as possible.

an LED can be drive at 50mA with POV pulses and only at 20mA continuous.

that allows for a much brigher light for a short duration to make up for the percentage of ON time.

on the other hand, a continuous on high output LED might be better.

knowing you have a signal, can you have a circuit that would then require refreshing in order to stay ON continuously ?

loose the signal for a second and the output of the circuit would shut off ? I was thinking about refreshing a cap that would keep a circuit powered. loose power to the cap, and the circuit turns off.

Okay, thanks for the info, just a bit more confused now.

Cossroads, you mentioned your board and 45V, I am confused by the 45V, the led's are 12v, I was hoping to use a car battery and solar panel to keep it charged.

I like your board on how simple it would be to wire up to, but I need a bit more detail on how it would be wired up to the led strips.

I thought I would wire it up similar to this guys project (less the copper tape)

but using the styrofoam like this one

https://www.sparkfun.com/tutorials/47

Sorry, got a little lost in the discussion.
Looking at these #s:
Working power 30leds/m:4-5W/M
60leds/m:8-10W/M
Working Current 30leds/m:1.7-2.1A/5M <<< Which do you have?
60leds/m:3.7A-4.2A/5M <<< Which do you have?
you’re gonna need a hefty power supply.
These currents come about because there are 3 LEDs in series every so many inches, and every 3 LEDs is in parallel with the others. TPIC6x595 can’t sink that much current.
You need a board like this for that much current. This has AOI516 or AOI518 N-channel MOSFETs with bases controlled by 74HC595 shift register, an Arduino is used to shift data in to be displayed.
Board is designed to be daisychained, so two boards for 64 segments. I only planned for 1A/transistor on these, so likely extra wire would be needed to added to the traces to beef up current capability. If you have MOSFETs already, we’d need a part number to see if they are logic level; or standard, which need 10V swing on the gates to fully turn them on/off.