Love Pong? Wear it on your wrist! via instructables

Time for another retro project, this time a wearable – always on – Pong Watch. Inspired by the classic video game, Pong.

Step 1: Parts List

Watch casing – Cheap 99p LED watch from eBay. This makes things a lot easier as I didn’t fancy designing or building a watch case. I just performed a few mods to it.
Display – Monochrome OLED with I2C interface. Just a few quid from eBay.
Processor – Microchip PIC 12F1840 8 pin Micro Controller from eBay for a few quid.
Battery – rechargeable Li-ion 052025 25mm x 20mm x 5mm from eBay for a few quid.
Li-ion charger – TP4056 Lithium charger module from eBay for a few quid.

Step 2: Write soft and Test

I used Microchip MPLABX to write some test code in C (attached) and downloaded it via PICKIT3 to the PIC 12F1840 and hooked it up to the OLED display. The PICKIT3 at this point was also supplying power to the circuit. The I2C was bit bashed in the code, but the PIC 12F1840 has a hardware I2C built in that I should really be using, that way the internal clock doesn’t need to run so fast saving on power. Unfortunately, it shares the same pins as the PICKIT3 programmer which interferes with the I2C pull ups meaning I would have to unplug the programmer to test which would result in me losing power to the device. It worked fine as it was and I decided I just wanted to get this thing built without exploring further features of the micro controller.

Full tutorial