When your climbing gym throws a “glow in the dark” party, how can you stand out? For [Martijn], the answer was obvious. He made a jacket adorned with 32 WS2812 addressable LEDs whose color is addressable depending on the altitude to which he has climbed.
The build is centered on an Arduino Pro Mini with a barometric sensor and an NRF24L01 for radio comms. A pair of pockets contain AA batteries for power, and he’s all set to climb.
A base station Arduino with the same set-up transmits an up-to-the-minute reading for ground level temperature, which is compared to the local reading from the barometric sensor and used to calculate a new color for the LEDs. A Kalman filter deals with noise on the pressure reading to assure a stable result. Arduino sketches for both ends are provided on the Hackaday.io page linked above.
The LEDs are mounted on the jacket’s stretch fabric with an excess of wire behind the scenes to cater for the stretch. You can see the resulting garment in the short YouTube video below the break.