Scoreboard Digit Display

[purplecobra777]

Hi I have a project that I am attempting and I hope I can describe it well enough for you to understand. I would like to create something like a scoreboard display. I want to control a single digit display with with either 10 on-off switches or 1 10-way switch (If I can find one).

The display is going to be set up with regular incandescent lightbulbs 4 wide by 7 tall with 2 more across the middle to create a digital "8" figure. (20 total bulbs)

The only part I cannot figure out is how to easily and inexpensively be able to change the display from one number to another. Ex. First switch is on, display shows "0"; switch 1 off and switch 2 on, display shows "1" etc.

My first thought was to have the first switch display "0" when turned on by running positive current through that switch to the corresponding lightbulbs and then through a common negative wire among all the lightbulbs. The problem with that is that the 10 switches share some of the same lightbulbs and eventually each switch will just turn on all the lightbulbs because the positive wires coming from the switches would all be connected.

I hope this was easy to understand and I can post a picture in the future if needed. Any help would be appreciated. Thank you.

 

[philba]

If I were doing this, I'd emulate a 7 segment display. Think of an 8 - there are 7 segments to it. 0-9 can be expressed as a set of 2 or more illuminated segments. You can use a relay or TRIAC to control each segment.

It isn't clear how you intend the user to control this so it's hard for me to know what to suggest. A crude solution is to use a 10 position, 7 pole rotary switch but that's going to get expensive, if you can find them. A more sophisticated approach is to use a 10 position BCD encoded switch with a BCD to 7 segment decoder. This will output a signal for each segment. You can use this to drive a transistor to control the relays or TRIACs.

 

[crutschow]

A simple way is to power the lamps from DC, such as connecting a bridge rectifier to the AC (it doesn't have to be filtered). Then you would wire each switch with a diode to each bulb (Each switch with one diode per lamp lit for that number. If you group any of the bulbs together as a segment for all the numbers, than you only need one diode per segment per switch). That way the switches are isolated and there is no interaction between them. Of course this takes a lot of diodes but diodes are relatively cheap. The other side of the lamps are all wired together in common to the other side of the bridge rectifier output.

You should be able to find a single-pole 10 position rotary switch to do the switching. Of course it has to handle the current from all 20 lamps being lit (number 8).