Glugg

Glugg is Swedish for a small opening in a wall. This one keeps an eye on the windows of a wood workshop.

An ESP32-S3 pairs with IKEA MYGGBETT door/window sensors and lights one LED per open window on an 8×8 LED panel. An ESP32-H2 is its Thread radio. It runs fully offline: no Wi-Fi, no app, no cloud.

It runs on a hand-soldered protoboard with two MYGGBETT. The firmware supports up to 64 sensors, one per LED.

Parts

All from Electrokit except the sensors and the LED panel. The same list is in bom.csv for their quick order form.

Part	Article no.	Qty
Waveshare ESP32-S3-Zero-N8R8, with headers	41036436	1
Waveshare ESP32-H2-Zero, with headers	41032832	1
8×8 WS2812 LED panel (not from Electrokit)		1
74HCT32 quad OR gate, used as a buffer	40381032	1
DIL socket 18-pin (holds the 74HCT32)	40410018	1
1N5817 Schottky diode	40315817	1
Resistor 330 Ω	40811233	1
Resistor 1 kΩ	40811310	1
Resistor 10 kΩ	40811410	1
Capacitor 1000 µF 16 V	41017694	1
Capacitor 100 nF	41015538	1
Screw terminal 2.54 mm, 3-pole	41002454	1
Prototype PCB 40×60 mm	41010656	1
IKEA MYGGBETT door/window sensor	from IKEA	up to 64

You'll also need a USB-C charger and cable, and solid-core wire.

Wiring

• Power comes from a USB-C charger plugged into the S3. The S3's 5V pin is the +5 V rail: it feeds the 74HCT32 and the LED panel directly, and the H2's 5V pin through the 1N5817.
• The S3's GPIO13 drives the LEDs through the 74HCT32 (into pins 9 and 10, out of pin 8) and the 330 Ω resistor. Tie the unused inputs to +5 V (pins 1, 2, 12, 13) or GND (pins 4, 5).
• The hole-by-hole protoboard layout is in docs/protoboard-small.svg (top) and docs/protoboard-small-wiring.svg (underside).
• The two boards talk over two crossed UART wires, with the 1 kΩ resistor at the S3 end.

A printed carrier board with the same circuit is in hardware/pcb/ (KiCad, rev A, not yet ordered).

Usage

Plug in the power. A dim white ring breathes out from the middle of the panel for 10–20 seconds while the network starts. Then each sensor's LED shows its window:

LED	Means
Amber	Window open
Off	Window closed, or no sensor in this slot
Green pulse	Pairing a sensor into this slot
Dim white	Sensor paired but hasn't reported yet
Blue blink	Sensor not heard from for 2 minutes (battery, range)

LED 1 is the first LED after the panel's DIN pad; LED 2 onwards follow the panel's data chain. To manage sensors, connect a computer to the S3's USB-C port and open its serial console (for example idf.py monitor):

pair 3497-011-2332            add a sensor on the lowest free LED
pair 3497-011-2332 slot 14    add a sensor on LED 14
list                          show the paired sensors
move 14 20                    put sensor 14 on LED 20 (swaps if 20 is used)
remove 3                      remove the sensor in slot 3
identify 3                    ask sensor 3 to blink its own light, if it has one
factory-reset confirm         remove every sensor and start over

Power and the console share the S3's USB-C port: unplug the charger and plug in the computer instead (Glugg restarts, and the computer powers it meanwhile). A USB-C hub with power pass-through lets you keep both connected.

Pairing

• Use the 11-digit Matter code printed on the sensor, not the yellow IKEA app code.
• Open the sensor's pairing window first: insert the battery or press its button once. It stays open for 15 minutes.
• Type pair and the code, and optionally slot and an LED number (1–64). Without a slot, the new sensor takes the lowest free one, so the first sensor gets LED 1.
• A sensor that's already paired somewhere else won't pair again until you factory reset it: hold the button for 10 seconds.
• If remove can't reach a sleeping sensor, factory reset it the same way before pairing it again.