Tennis is notorious for its weird and mysterious scoring guidelines — doubtless an intentional technique by posh tennis golf equipment to maintain out the riffraff. I imply, love, 15, 30, 40, and deuce? What even is that? These enigmatic guidelines inevitably result in arguments and fist fights between novice tennis gamers, which is an actual downside for the aforementioned tennis golf equipment. To keep away from befuddlement amongst new gamers and to maintain these golf equipment from changing into battle zones, 0xBERNDOG created this pocket scoreboard that does all of the onerous work of monitoring factors.
Conceptually, that is fairly straightforward to grasp. It’s only a small system with buttons and a display screen that tennis gamers can work together with to maintain monitor of the rating in a match. After a number of weeks of learning tennis guidelines, most makers may construct a tool with these options in a day with an Arduino. However 0xBERNDOG gave himself some further function necessities that made it a a lot, far more difficult endeavor.
The requirement with the largest influence was a protracted battery life on a small battery — an extraordinarily lengthy battery life on a very small battery. That battery is a small coin cell (precise kind unspecified) and 0xBERNDOG says it might final a whopping 20 years when the system is in idle mode (system on, however display screen off). That’s as a result of it attracts lower than a microamp in that state. Even with the display screen on 24/7, the battery would final about 200 days.
To make that doable, 0xBERNDOG put loads of effort into optimizing energy effectivity. The system runs an STM32L4 ultra-low-power microcontroller and the display screen is a Sharp reminiscence LCD from Adafruit (0xBERNDOG says it’s a Toshiba, however we’re fairly positive he meant Sharp). These shows bridge the hole between e-ink and customary LCDs, providing quick refresh charges and really low energy utilization. The parts go on a customized PCB that matches in a customized 3D-printed enclosure that appears fairly good.
Even with all of that, 0xBERNDOG needed to do loads of work with the firmware to make the system sip energy so frugally. He constructed that firmware utilizing FreeRTOS with a HAL ({Hardware} Abstraction Layer), which let him maintain the microcontroller in one thing like a deep sleep till an occasion (like a button press or display screen replace) requires consideration.
Now we simply have to cross our fingers and hope 0xBERNDOG builds an analogous system to keep away from bloodshed on the pickleball courts.
