SWAMP GLOW

ATOM Matrix — 24 × 24mm. 25 RGB LEDs. Accelerometer. Wi-Fi. USB-C. ~$15.

The ATOM Matrix has everything built in. No shields, no wiring, no breadboard.

Download the firmware zip and extract it on your computer.

Connect the ATOM Matrix via USB-C. It shows up as a drive called CIRCUITPY. Copy the swamp-glow folder contents onto the drive. The device reboots automatically and starts running. It boots in about 2 seconds.

What happens on boot:

• The 5×5 LED grid lights up with a default green glow
• The accelerometer starts reading in the background
• Saved settings load from flash (color, brightness, pattern, timing)

ATOM Matrix inside the waterproof housing. LED grid facing out. Swamp green.

Hold the button for 3 seconds. The LED grid turns yellow — the ATOM Matrix is now running as a Wi-Fi access point.

The setup page is embedded in the firmware — a single HTML file served from the device. No internet needed. Dark background, green accents, swamp glow theme. It looks like it belongs to the book.

Preview the device page →

The AP page also lets you enter Wi-Fi credentials for Step 3 — but that’s optional. You can use the device with just the AP page forever.

On the AP setup page, there’s a section for Wi-Fi credentials. Enter your network name and password. Hit save. The device reboots, connects to your Wi-Fi, and now you can reach it from any device on the same network.

With Wi-Fi, you can control pucks from inside the house. No need to walk out. Change a color, adjust a pattern, turn one off — all from your browser.

If you have multiple pucks on the same network, each one has its own IP. Bookmark them. Control any puck from any browser on your network.

The ATOM Matrix runs CircuitPython with the Tick library. All the code lives on the CIRCUITPY drive. Here’s what it does:

LED Control

The 25 WS2812C LEDs are on GPIO 27. The NeoPixel driver handles them:

import board
import neopixel
import math, time

NUM_LEDS = 25
np = neopixel.NeoPixel(board.G27, NUM_LEDS, auto_write=False)

# Set all 25 LEDs to swamp green
def set_color(r, g, b):
    np.fill((r, g, b))
    np.show()

# Breathe — fade brightness up and down
def breathe(r, g, b, max_bright=20):
    t = time.monotonic()
    val = (math.sin(t * 0.5) + 1) / 2  # 0.0 to 1.0
    scale = 2 + int(val * max_bright)
    np.fill((r * scale // 255, g * scale // 255, b * scale // 255))
    np.show()

Timing Loop

Two hours on, ten minutes dark — just a timer:

on_duration  = 2 * 60 * 60  # 2 hours in seconds
off_duration = 10 * 60      # 10 minutes in seconds
cycle_start  = time.monotonic()
glowing      = True

while True:
    elapsed = time.monotonic() - cycle_start

    if glowing and elapsed >= on_duration:
        set_color(0, 0, 0)    # LEDs off
        glowing = False
        cycle_start = time.monotonic()

    elif not glowing and elapsed >= off_duration:
        glowing = True
        cycle_start = time.monotonic()

    if glowing:
        breathe(5, 40, 3)   # swamp green pulse

    time.sleep(0.02)

Motion Detection

The MPU6886 accelerometer detects if someone picks up the puck:

import busio
import adafruit_mpu6886

i2c = busio.I2C(board.G21, board.G25)
imu = adafruit_mpu6886.MPU6886(i2c)

def check_motion():
    ax, ay, az = imu.acceleration
    accel = math.sqrt(ax*ax + ay*ay + az*az)

    # Sitting still = ~9.8 m/s². Picked up = spike above 15
    if accel > 15:
        set_color(40, 0, 0)  # flash red
        time.sleep(0.5)
        set_color(5, 40, 3)   # back to green

AP Setup Page

When you hold the button, the device starts a web server:

import wifi
import socketpool
from adafruit_httpserver import Server, Request, Response

# Start AP mode
wifi.radio.start_ap(ssid="Tick", password="11111111")

pool = socketpool.SocketPool(wifi.radio)
server = Server(pool, "/static")

@server.route("/")
def index(request: Request):
    return Response(request, body=SETUP_HTML,
                    content_type="text/html")

@server.route("/save", methods=["POST"])
def save(request: Request):
    save_settings(request.form_data)
    return Response(request, body="Saved. Rebooting...")

server.serve_forever(str(wifi.radio.ipv4_address_ap))

Same housing as the simple Swamp Glow versions:

• ATOM Matrix inside a plastic ornament ball, LED grid facing out
• USB-C cable out through a sealed hole to a battery pack
• Aquarium silicone on the seam
• Sand the outside, one coat of green glass paint

No soldering. No wiring. The ATOM Matrix is the whole circuit.

The device runs CircuitPython. When you plug it into a computer, it shows up as a USB drive called CIRCUITPY. The Tick code is a set of .py files on that drive. To update:

github.com/i4seer/tick-swamp-glow

CIRCUITPY/
  code.py          ← main program
  tick_led.py      ← LED patterns
  tick_web.py      ← AP setup page
  settings.toml    ← saved settings

Updates are optional. The device works out of the box. But if i4Seer releases new patterns, bug fixes, or features — this is how you get them. No special tools. Just copy files.