Very large seven segment displays

[Divan]

I would like to build a scoreboard for my local rugby club.

I am sceptic of using LEDs because of their lack of visibilty during daytime. As the majority of our games during a season is played during the daytime, I am looking for something other than LEDs to create large seven segments.

Has anyone ever seen large mechanical seven segments and or does anyone know where I can find info on building them.

I am looking for something like this:

 

[tcmtech]

Ultra bright green and red LED's are easy to see in daylight. Just use a contrasting background for the numbers to further amplify the visibility effects

Over driven florescent tubes work well too but will have a shorter life expectancy.

 

[ChrisP58]

As has been said, there are daylight readable LEDs out there. Around my city I know of a few LED advertising billboards that allow the sign owner to change the image every few seconds.

But, if you do want to go mechanical, I would have a vinyl sign maker print a vertical strip of the numbers 0-9. Put the strip on a couple of rollers and use a motor to run the strip up and down to show the number you want.

How big do you want the numbers to be?

 

[Divan]

I'm looking for a character height of about 12"-15". I've built a large electronic scoreboard before (in University), building the large 7 segments out of 8mm LED's. More recently I built a count down timer using 10mm LEDs to build the segements. They both work great indoors and in the shade, but in sunlight they just lack great visibility.

What I'm looking to build now is a scoreboard that needs to be visible at over 100yards in a 45-60 degree angle during midday. Thats why I thought it better to move away from LEDs.

My problem when using the LEDs were that even against a black background the ultrabright 10mm red LEDs were dificult to distinguish between lit LEDs and unlit LEDs brigthened by sunlight. Easy enough at 40yards, but 100+ not so great. Unless I'm doing something wrong.

I found a company in Poland making these, unfortunately I have don't have much knowledge of electromagnets, and they are quite expensive!!

 

[Sangoma]

What about white/black (each at 90deg to each other) mechanical segments, turning them with RC servos.

Very stoneage and steam powered, but very easy to build.

Could even use a modified 7 channel transmitter for each digit for remote operation

 

[Menticol]

What about white/black (each at 90deg to each other) mechanical segments, turning them with RC servos.

Very stoneage and steam powered, but very easy to build.

Could even use a modified 7 channel transmitter for each digit for remote operation

Or maybe balsa (or another light wood) sheets, mounted on a spring loaded hinge*. You can open them using a solenoid behind each sheet. (dark: wood on the way) (white: looking through the sign).

* Finally I found how's called in English

 

[ChrisP58]

The on/off contrast of LEDs would probably be enhanced by putting them behind a matte finished, smokey sheet of plastic. That should keep the sunlight from brightening the off LEDs.

 

[crutschow]

Here are some electro-mechanical digits but the maximum size is 9".

 

[Sangoma]

Or maybe balsa (or another light wood) sheets, mounted on a spring loaded hinge*. You can open them using a solenoid behind each sheet. (dark: wood on the way) (white: looking through the sign).

* Finally I found how's called in English

Solenoids would work, but servos are easier to find and cheaper, and very easy to drive with a pic or atmega, or even 555 timers! I think right-angled PVC (in all the hardware stores here) would be more durable than wood, though 1 1/2" right-angled ramin is quite inexpensive.

 

[jbeng]

Many years ago, I designed a large digit display sign which used electromechanical digits for a company where I was employed. We made two versions, one had 6-inch displays and the other had 12-inch displays. The display modules were made by Staver and were "Signalex" brand displays. The original Signalex product line ranged from 1.5-inch to 24-inch displays.

Apparently, when the owners of the Staver Co. decided to retire, they sold the brand to another company who in turn sold it to someone else. The company which now owns the Signalex brand is called "Scoretronics" (Link here), but they have discontinued all but the 2-inch and 4-inch size displays. You can still find some of the old, larger displays on eBay occasionally, but they are usually quite expensive.

I definitely like the idea of using small RC servos to move the segments. I had thought of using painted cardboard tubes (like paper towel cores) for the segments. They would be lightweight, cheap, easy to obtain, etc. and would require only a very small servo to move them.

 

[Pommie]

Another thing to consider is the small solenoids that are used to switch points on model railways. The second one on this page should manage. And only around $10.

Edit. it appears that images aren't working.

Mike.

 

[dr pepper]

Being a builder of strange electronic clocks I'd like to come accross something like that also.

I've seen a few examples on youtube where people have made them, small dc motors used as solenoids with a spring return is by far the cheapest solution for the actuators.

 

[Divan]

I had a look at the scoretronics website, those look perfect. Sent them an email requesting priceing on 12" digits. Problem is that I am in Cape Town, South Africa. So converting it into SA-Rands and including shipping costs I am pretty sure it won't be affordable.

They use a dual winding coil requiring a 50ms pulse of 80mA for each segment. I found one requiring a 50ms pulse of 360mA. which is quite a lot of current for one single segment. I can work around that by only switching a single segment at a time, the only problem is that the solenoid only gives me a 4mm stroke.

How do I turn a 4mm stroke into a visible/non-visible segment??

 

[Sangoma]

I had a look at the scoretronics website, those look perfect. Sent them an email requesting priceing on 12" digits. Problem is that I am in Cape Town, South Africa. So converting it into SA-Rands and including shipping costs I am pretty sure it won't be affordable.

They use a dual winding coil requiring a 50ms pulse of 80mA for each segment. I found one requiring a 50ms pulse of 360mA. which is quite a lot of current for one single segment. I can work around that by only switching a single segment at a time, the only problem is that the solenoid only gives me a 4mm stroke.

How do I turn a 4mm stroke into a visible/non-visible segment??

Put the 4mm near the pivot point, or use a lever

 

[dr pepper]

This ones home made.
You could make all the segments move at the same time to make it a little more professional.
It can be done.

https://www.youtube.com/watch?v=sMyecsyzkTU

 

[Divan]

I found that video a couple of weeks ago. I sent the uploader a message asking about the mechanics he used but never got a reply. I sent him one again now, hopefully he replies this time.

I know it can be done... the question is how??

The electronic part isn't my problem, but I can't start the controlling hardware/software without knowing exactly how my digits will work...

 

[dr pepper]

It looks like each segment is on a hinge made from a rod/tube with a recoil spring holding it 'off', and theres a cable going through the backplane to the actuator, the actuator could be a bellcrank connected to a solenoid to increase the movement.
A cheaper way as I mentioned would be to fit a small pulley on a little dc motor, then couple this to the digit via a cable, then use a current limiting resistor in series with the motor, as one the digit is operated the motor would be stalled, or if your using a micro you could do this with pwm.

 

[Sangoma]

You can get servos for less than $3.50 that will give 1kg/cm torque, and turn through the 90deg needed, no extra mechanical parts needed.

 

[dr pepper]

That being the case thats a excellent idea, would they be from china on ebay?, might get some at that price.

 

[Sangoma]

That being the case thats a excellent idea, would they be from china on ebay?, might get some at that price.

yes from China, but not ebay, look at www.hobbyking.com and look for their own brand. You can also get a small servo tester for a few pounds, handy for testing without the final circuit, or testing locally if remote controlled.

I have bought from ebay, but quality and delivery is not consistent.