aclock

Files to make an overcomplicated clock.

I want a clock that indicates:

• The time
• Daylight / nighttime hours
• General telemetry status for the rest of the homelab

The general layout is to have a big (digital) display in the center, and use LEDs around the edge to indicate the daylight/nighttime hours.

Active hardware

• Raspberry Pi of some flavor

• 1 meter of RGBW LED strip with individually-addressible LEDs (NeoPixel).

  Product page, Datasheet

• 16x32 RGB LED matrix, 6mm pitch (so, 192mm x 6mm).

  Product page, Datasheet

• LED matrix + RTC HAT - driver board for the matrix, sized to Raspberry Pi

  Product page, Matrix driver library

• I2c CO2 / Temp / Humidity sensor

  I have a Rust driver for this kicking around somewhere, but there's also the Adafruit library.

  Product page, Datasheet, Library source, Model

Passive hardware

I'm treating this as an opportunity to learn a bit of CAD, and spin up a 3d printer.

• Central, rectangular frame: holds LED matrix in the center, Pi / HAT / SCD30 below

  Based on some other prints, this may be too big / take too long to be practical; I may want to split it up. And see dimension considerations below.

• Clip-ons to the center frame to make the edge round, and mount the LED strip on it

Playing around with some dimensions - ignoring print width:

• 1m radius gives 318.3mm diameter. We can have a little give /gap at the bottom and make it a round 320mm diameter.
• 320mm becomes the diagonal of an inscribed square; 320mm / sqrt(2) = 226.27mm as the side of the square.
• We take 96mm out of that for the LED matrix; and it's centered, so we only get half of the remainder to fit in the RPi. That's about 65mm; a Pi board is 56.5mm wide (86mm-odd long). That gives us not quite 10mm of framing space to work with.

Software

Given that the libraries seem to be available in Python, it may be easiest to start there.

Matrix driver library for running the clock face. It's actually C++, with Python bindings- so will require "manual" install. There's a reference install script but- it's interactive, so, no.

Astral for computing rise/set times

Adafruit-Blinka provides a compatibility layer, adding CircuitPython to regular Python (per their guide) for the Neopixel library.

The Neopixel guide points to rpi_ws281x and adafruit-circuitpython-neopixel from PIP as the other sources.