Instructions | Building a Basketball Hoop Alarm Clock

1

Validate the sensor first

Before designing any PCB, prove your detection method works with the real object in the real environment. We spent three days on this and it saved us weeks.
2

Pick an MCU for your power budget, not your feature list

The nRF52840 was right because idle current mattered more than WiFi.
3

Structure firmware around tasks from day one

Zephyr's threading model kept the sensor loop deterministic even while BLE was active.
4

Design the PCB with test points

We added pads on every power rail and the I2C lines — worth the small board space cost.
5

Print the enclosure early

Physical fit problems surface fast and cheaply in 3D prints
6

Test on battery, not USB

Power behavior changes completely once you're running off a LiPo.

Building a Basketball Hoop Alarm Clock