Martin Raynsford's Pinball Clock Makes It Harder to Lose Time While Flipping and Bumping

Maker Martin Raynsford has given a pinball machine a little thematically-appropriate upgrade in the form of a secondary display — designed to display the time, to avoid lost hours hitting bumpers and flippers.

"We're now the proud owners of a Stargate pinball machine which we love but it's very possible to lose track of time while we're playing," Raynsford explains of the reason behind the upgrade. "I decided that we needed a clock in the room and it would be cool if it was in keeping with the pinball theme."

To achieve that, Raynsford picked up a MAX7219-powered 8×32 LED dot-matrix display panel — looking not hugely dissimilar to the display the pinball machine uses for its score-keeping. The display is connected, via SPI, to a Wemos LOLIN D1 Mini microcontroller, which in turn is built around the Espressif ESP-8266EX module — giving it what it needs to feed the display along with a Wi-Fi connection for network time updates.

"I was keen to replicate the style of the score increasing during a game of pinball, the pinball score only increases in multiples of ten so I added a zero onto the end of the second counter," Raynsford explains of the clock's somewhat unusual time format.

"On our pinball machine, most targets increase the score in thousands with big shots giving millions so it make sense to use those as the hours minutes respectively. This means the left most characters represent the actual time hh,mm. To keep the formatting correct there has to be an additional zero inserted between the minutes and seconds. The hh.mm0.ss0 format initially looks a bit confusing but if you concentrate on the first four characters it's really easy to read."

The finished clock is installed in a laser-cut plywood housing, painted black to make it less obtrusive, and sits on top of the pinball machine below the real display. "Once initialized the main loop of the program simply checks on the time and updates the display at one second intervals," Raynsford says.

"The majority of the code for this program is about setting up the Wi-Fi and NTP server and confirming that they are connected before progressing to the main loop."

More information, along with the project's source code and an SVG file for the laser-cut housing, is available on Raynsford's blog.