LED Copper String Zigbee Controller

Zigbee-controlled LED copper string light using a TB6612 H-bridge driver. The LED strip has a special design where one polarity lights half the LEDs and reverse polarity lights the other half. Rapid polarity alternation makes both halves appear lit simultaneously.

Hardware

Target: Pro Micro nRF52840 (SuperMini, nice!nano compatible)

TB6612 Wiring

TB6612 Pin	nRF52840	Function
PWMA	P0.22	Brightness (PWM)
AIN1	P0.20	Polarity control
AIN2	P0.17	Polarity control
STANDBY	P0.24	Power save (LOW when OFF)
VM	5V	Motor supply
VCC	3.3V	Logic supply
GND	GND	Ground

Other Connections

Function	Pin
Pairing Button	P0.06 (active low, internal pull-up)
Status LED	P0.15 (onboard)

Building

./build.sh          # Build
./build.sh flash    # Build and flash via J-Link
./build.sh clean    # Clean rebuild

First build downloads the nRF Connect SDK (~4GB).

Output Files

File	Purpose
build/firmware/zephyr/zephyr.signed.hex	Flash via J-Link
build/dfu_multi_image.bin	OTA update binary
build/*.zigbee	Zigbee OTA file with headers

Zigbee

• Device Type: Dimmable Light (0x0101)
• Clusters: Basic, Identify, Groups, Scenes, On/Off, Level Control
• Model: LEDCopperV1
• OTA: Supported via MCUboot

Pairing

1. Hold button for 3 seconds to reset/enter pairing mode
2. Status LED blinks when not joined
3. Enable pairing in Zigbee2MQTT/coordinator

Operation

• ON: STANDBY high, AIN1/AIN2 alternate at 100Hz, PWM controls brightness
• OFF: STANDBY low (power save), PWM off
• Brightness: CIE 1931 perceptual correction for smooth dimming
• Transitions: Smooth fade between brightness levels

License

MIT