Last year, my uncles asked me to design an electronic table tennis scoreboard. Apparently, what they wanted wasn’t for sale (at least not in New Zealand). Since they’re very enthusiastic about the game, I agreed and created a design. It features:
- Keeping track of scores, number of games won, and timeouts;
- Remote control over Wi-Fi using a phone or tablet;
- Adjustable screen colour and brightness;
I’m using an ESP32 microcontroller for this project. It runs an HTTP web server that players can access to update scores wirelessly. I think it’s pretty neat!
I’ve designed the scoreboard to basically be a bunch of lasercut acrylic and plexiglass parts. Assembling the units was pretty easy after all components were available: putting together a single unit took maybe four hours, with most of our time spent on gluing the semitranslucent pieces of plexiglass to the front part of the screen.
The electronics for the screen are just two circuit boards that are perfect mirrors of each other. The LEDs are WS2813 type, laid out such that they represent a total of three 7-segment displays and one timeout indicator per board (player). I went for two smaller boards because production costs for a single large board would be too high and would furthermore restrict manufacturing options by the supplier like already placing surface-mount components (SMT).
Each segment in a 7-segment display has multiple (either two or four, depending on size) LEDs behind it. To make the light within a segment as uniform as possible, the LEDs are set back approximately 20 mm from the very front of the unit. Moreover, I use semitranslucent plexiglass inlays for each segment to further disperse the light throughout the segment. This gives a nice and soft effect.
I had to make a tradeoff here. Setting the LEDs further back does improve the overall dispersion of the light within a segment, but it decreases the maximum viewing angle of the screen. I was aware of this tradeoff when creating the design, and ensured that we could change the LED depth later by adding or removing lasercut foam layers within the unit.
Hope you like it. If you want to make one for yourself, all designs are available on my Github page.