LED Lighting Controller Modification

⚠️ WARNING - MAINS POWER SAFETY ⚠️

Working with mains power is extremely dangerous and can result in serious injury, electric shock, or death.

• Disconnect all connections to mains power before starting any work on this project.
• This PCB does not provide galvanic isolation. Be aware that the low-voltage components connected to the circuit may be at mains potential.
• Only proceed if you have adequate knowledge of electrical safety and experience working with mains-voltage systems.
• Consider consulting a qualified electrician if in doubt.

Proceed at your own risk.

This project aims to enhance the functionality of a lighting unit originally produced by Lidl™'s LIVARNO™ brand (Type 0452602). The original unit uses an unbranded 8-pin microcontroller for control, which does not retain its settings when mains power is switched off. This project replaces the original processor with an ATtiny™85 microcontroller to add persistent storage of settings and maintain compatibility with the original IR remote control.

Features

• IR Remote Control: Full support for controlling the lighting unit via an NEC™ protocol-compatible IR remote control.
• Independent Control: Adjust cold white and warm white LED strings independently.
• Brightness and Color Adjustment:
  • Smooth fading between color temperatures.
  • Adjustable brightness levels.
• Persistent Settings:
  • Store color and brightness settings in EEPROM.
  • Reload saved settings after power cycling.
• Night Mode: Activate a low-intensity nightlight setting.
• Preset Support: Quickly switch between predefined color and brightness presets.
• Timer: Enable oder disable a 30min lights-off timer.

Hardware Requirements

• Microcontroller: ATtiny85 running at 8 MHz with built-in EEPROM for setting storage.
• LED Channels:
  • Cold white LED string connected to PB1 (PWM output).
  • Warm white LED string connected to PB4 (PWM output).
• Timer:
  • using WDT interrupt for 30 min timer
• IR Receiver:
  • NEC-compatible IR receiver connected to PB2.

Pin Configuration

Pin	Function	Usage
1	PB5
2	PB3
3	OC1B	Warm white LED PWM
4	GND	0V
5	PB0
6	OC1A	Cold white LED PWM
7	PB2	IR receiver input
8	Vcc	+5V

Key Functionality

• IR Commands:

  • Power toggle (on/off).
  • Adjust brightness (increase/decrease).
  • Change color temperature (colder/warmer white).
  • Activate nightlight mode.
  • Store and recall settings.
  • Quickly set brightness levels (10%, 50%, 100%).
  • Activate/deactivate 30 min lights-off timer

• Fading:

  • Smooth transitions between brightness levels and color temperatures.

Development Notes

• Microcontroller Programming:
  • The ATtiny85 is programmed using an ISP programmer.
• Development Board:
  • The project was developed using a Digispark ATtiny85 board for initial testing.
• PWM Configuration:
  • Timer1 is used for generating PWM signals with 8-bit resolution.
• IR remote control
  • Timer0 is used for analyzing NEC remote control codes.
• WDT interrupt
  • WDT generates aprox. every second an interrupt used for the timer funcion.

How It Works

1. Startup:

   • The program initializes the ATtiny85, loads stored settings from EEPROM, and fades in the LED strings to the last saved state.

2. IR Command Processing:

   • The IR receiver decodes commands from the remote control, which are processed to adjust brightness, color temperature, or mode.

3. Persistent Storage:

   • Settings are stored in EEPROM to ensure they are retained after power loss.

4. PWM Control:

   • Independent PWM signals are generated for the cold and warm white LED channels, enabling precise brightness control.

Installation

1. Programming:

   • Flash the provided program onto the ATtiny85 using an ISP programmer and avrdude.

2. Hardware Setup:

   • Replace the original microcontroller with the ATtiny85.
   • It is recommended to mount the ATtiny85 upside down. This orientation aligns Pin 3 and Pin 4 with the existing PCB traces for better compatibility.
   • Connect Vcc, the LED strings and IR receiver input to the appropriate pins as described in the Pin Configuration section.

3. Testing:

   • Use the original IR remote control to verify functionality.

Acknowledgments

This project enhances the LIVARNO™ LED lighting unit by adding modern functionality while maintaining compatibility with its original design. The ATtiny™85 microcontroller provides an efficient and reliable solution for embedded systems with limited resources. This ReadMe.md-file creation was assisted by ChatGPT.

License

This project is open-source and available under the MIT License.