So, I have some experience with electronics, particularly with pinball machine, jukeboxes, amplifiers, industrial controls and automotive components. I have an interest in lots of vintage items and I also like putting them to use. Since I do not have my own sports team, but I have always liked old score boards, so I wanted to use an old score board as a clock/calendar. I want to use the 'Time' digits on a basketball scoreboard to act as a clock. I then want to use the 'Home' and 'Visitor' scores for month and day. Any ideas of how to do this? Below is an example of what I would want to get a hold of.

 

What you need to do will depend on what kind of electronics the board you get uses. Ideally, it would be split into drivers that drive the display elements and then logic that determines what will be displayed. If you can split these two apart so that you can use the original drivers, that will make life a lot easier. Then it's just a matter of the logic to determine what to display (an MCU is a good way to go for that) and probably some simply interface electronics to marry the output of the logic to the input of the drivers.

 

What you need to do will depend on what kind of electronics the board you get uses. Ideally, it would be split into drivers that drive the display elements and then logic that determines what will be displayed. If you can split these two apart so that you can use the original drivers, that will make life a lot easier. Then it's just a matter of the logic to determine what to display (an MCU is a good way to go for that) and probably some simply interface electronics to marry the output of the logic to the input of the drivers.

So getting a unit with controls is preferred vs. finding a unit that sans controls.....I think I can do that. Most of these seem to be pretty simple devices.

Here is a posting about a similar idea:
http://www.selectric.org/nevco/

 

I don't think the control box will prove very useful, so I wouldn't pay much extra to have one.

I would look at display board to identify the driver chips that power the the bulbs and the decoder chips that driver the driver chips. With that info, taking over the score board for your own nefarious purposes may be relatively simple. Figuring out the mapping of the bulbs to display the digits you want may be tedious.

 

Very specificly, knowing the format of the data that is received from wherever it is sent from is what you need to know. That could range from binary data from rotary switches to data strings sent from a laptop computer. That will determine how much "Brain Power" your addition has to provide. So you would start by looking at the connection between the remote data entry device and the scoreboard. If it is an RJ45 connection like network cables use, the project might be all software, while if it is a 48 circuit connector of some sort there will be hardware to create. Depending on the age of the scoreboard it might even have stepping relays inside, like a high school football scoreboard from 1963 had. The control box had a push-button to advance each numerical display. A current scoreboard might be controlled by a smart cell-phone app, and be much more challenging to interface with.

 

Pretty sure it is not an RJ45 plug. Much more akin to an older Jones plug. I was thinking that the software part of this would be similar to that of one of the old time/date displays you used to see in front of banks and town halls. Those units would use the same configuration of light bulbs to simulate digital numbers.

 

OK, with a Jones plug, probably you will not need to deal wot a processor inside the display. But there may be some digital counters, a separate one for each section with numbers. It that is the scoreboard you intend to use, shown in post #1, it seems that you will have adequate room to work inside it. are those 40 watt reflector back incandescent light bulbs that I see? If so, that will be a quite large clock/calendar display. You may even be able to add a dimmer option.
Let us see when you open it up. If those are 120 volt bulbs then the driver circuits will be an interesting exercise.

 

Looks like they are 161 wedge bases. There are a couple types of scoreboards I would like to get, but the feasibility of the project comes first. If I can't do the clock, I don't really want it. Looks like the best option is one with a Jones plug for simplicity.

 

If the scoreboard is the "dumb" kind with a huge connector with a pin for each bulb (actual switching is done in a separate control box), the task becomes tedious but easy to do. You'd have to build circuit boards with triac drivers for each bulb (or switch to LED bulbs and MOSFETs) with peripheral expander chips switching the drivers, but then the most complicated part is sorting out all the connections. I'd use I2C expander chips with a board for each digit for simplicity.

Do consider changing to LED bulbs – that many incandescent bulbs will generate a lot of heat. Also, using LEDs gets away from the complications of switching line voltage.

 

I have a large quantity of solid state stuff hanging around from the 70's, 80's and 90's that is left over from working on pinball circuit boards. Honestly, 99% of the work I have done in the past has been repair and part swapping. I don't know enough to get started. When you mention triacs, are you talking about 555 IC chips or similar? If I had a simple diagram, I'm sure I could build it.

 

A "triac" is a semiconductor device used mostly for controlling both polarities of AC power. Based on the magnitude and timing of the control signal it will switch into conduction at veried times during every cycle of the AC supply voltage.
It would be one way of controlling the light bulbs in the scoreboard shown in post #1
If you have a diagram of that score board to share with us a lot of useful suggestions will arrive to suggest different schemes to achieve the stated goal. This will be a fun sort of project, I am sure of that.

 

Here is a video of a scoreboard of the same make and model that I am going to buy tomorrow

There is a pretty good sized stepper unit in there, I think that is for the clock. I'm betting that the stepper should be replaced with something more modern. I'll take photos of the unit once I get it home. I plan on converting the unit to LED instead of incandescent to get wattage down from 800 to something a little more efficient, LED's would bring it down to 180 watts.

 

Hang onto the stepper because it is the simple way to convert increments into a seven segment display, and it is already wired to one of those. If it is already wired to the time display it saves a whole lot of wiring. Just add a circuit to pulse it once per minute. And add a reset trigger for the count after 12:00. And another reset for the count after 24:00, in case you want it to display in the 24 hour format. Certainly the steppers can be replaced with "something more modern" but the reduction in power consumption would not be so great. Steppers draw no power at all except when incrementing or resetting.
It might be that the other displays also have stepper relay drivers, that would certainly be the simple way to control a digital display.
The less obvious benefit of a stepper drive time display is that short power disruptions will not return it to 12:00 flashing. And depending on the power source for the minutes pulses you might not lose any time at all.

 

Makes sense about the stepper. I can keep that in there no problem. I have heard that these units have selenium rectifiers in them and they can go bad and take the stepper system with them. I would replace that right away and put in a newer rectifier and replace any diodes in the system if there are any.

 

Selenium rectifiers certainly do fail eventually. Understand that the replacement silicon diodes have a much lower forward voltage drop. That may not matter in many places, BUT check the voltages versus voltage ratings when you do the replacements.

 

Ok, got the unit home, pulled the covers off and here is what I have found. Not sure where to start, but here are some photos.
Here is a shot of the back of the light boards.

 

Those are more than just seven segment display PCBs. As I look closer I see that not all of the positions are populated. So you have some interesting options available. Evidently one style of PCB was used for alpha-numeric displays also. But here, only seven segments.
And I see no sign of any decoder circuits at all.

 

Here are the control boxes for the score digits.


Not sure what this unit is for, but I'm sure I will figure it out.


Here is the base of the control boxes.


Here is the socket and the wiring attaching to the digit display board.


Here is the control box for the clock.


The control box has a number of jones plug sockets and is the power supply for the unit.


Here is the stepper motor inside of the control box.


Fuses

 

Any thoughts on what to start sorting out? Any thoughts on how to control the unit? My ultimate goal is to do the following:
1) Clock works as a regular 12 hour clock
2) Home/Visitor = Month/Day
3) Period 1, 2, 3, 4 changes with the seasons.
Period 1 = Dec. 22 - Mar. 21
Period 2 = Mar. 22 - June 21
Period 3 = June 22 - Sept. 21
Period 4 = Sept. 22 - Dec. 21

 

Those are more than just seven segment display PCBs. As I look closer I see that not all of the positions are populated. So you have some interesting options available. Evidently one style of PCB was used for alpha-numeric displays also. But here, only seven segments.
And I see no sign of any decoder circuits at all.

The extra bulbs and bases were found in the bottom of the scoreboard.