Touch LED Lamp Controller

A battery-powered, touch-controlled LED lamp built with an Arduino (ATmega328P). Tap to toggle the lamp on/off, hold to smoothly dim. Brightness is saved to EEPROM and the microcontroller enters deep sleep when the lamp is off for minimal power consumption.

Features

• Touch on/off - Quick tap toggles the lamp
• Smooth dimming - Hold to adjust brightness continuously
• Direction memory - Dimming direction alternates each hold (up then down, etc.)
• Brightness persistence - Last brightness level saved to EEPROM and restored on power-up
• Deep sleep - MCU enters SLEEP_MODE_PWR_DOWN when lamp is off, waking on touch via interrupt
• Ultrasonic PWM - Timer1 set to ~31 kHz to eliminate audible coil whine from the boost converter
• Power optimization - Unused peripherals (ADC, SPI, TWI, USART, Timer2) disabled to reduce current draw

3D printed design for desk lamp: https://makerworld.com/en/models/2407165

Short assemble video and demonstration:

Hardware

Components

Component	Purpose
Arduino Nano / ATmega328P	Microcontroller
TTP223	Capacitive touch sensor
TP4056	Li-Ion battery charger module
Boost converter (set to 12 V)	Steps up battery voltage for LED strip
IRLZ44N N-channel MOSFET	Switches the 12 V LED strip via PWM
10 kΩ resistor	Gate pull-down on IRLZ44N (ensures LED off when MCU is unpowered)
100 Ω resistor	Gate series resistor (limits ringing / inrush)
12 V LED strip	Light output
Li-Ion 18650 battery	Power source

TTP223 Configuration

Jumper	Setting	Effect
A	OPEN	Active HIGH output
B	OPEN	Momentary mode

Wiring

TTP223 OUT ──> Arduino Pin 2  (INT0, wake interrupt)
Arduino Pin 9 ──> 100 Ohm ──> IRLZ44N Gate
                                  │
                                10k Ohm
                                  │
                                 GND

IRLZ44N Drain ──> LED Strip (−)
IRLZ44N Source ──> GND

Boost Converter 12 V OUT ──> LED Strip (+)
Battery (+) ──> TP4056 B+ ──> Boost Converter IN

How It Works

1. Startup - PWM frequency is set to ~31 kHz (ultrasonic). The saved brightness is loaded from EEPROM. The lamp starts in the OFF state and immediately enters deep sleep.

2. Touch to wake - A rising edge on Pin 2 fires an interrupt that wakes the MCU from sleep, toggles the lamp ON at the saved brightness.

3. Tap (< 300 ms) - Toggles the lamp on or off.

4. Hold (>= 300 ms) - While the lamp is on, brightness ramps up or down. On release, the direction reverses for the next hold. The new brightness is saved to EEPROM after a 2-second debounce delay.

5. Sleep - When the lamp is off and the touch pin is idle, the MCU enters SLEEP_MODE_PWR_DOWN, drawing minimal current until the next touch.

Software Configuration

Key constants in the sketch:

Constant	Default	Description
HOLD_THRESHOLD	300 ms	Tap vs hold detection threshold
DIM_STEP_INTERVAL	20 ms	Speed of brightness ramping
DIM_STEP	3	Brightness change per step (0-255 range)
MIN_BRIGHTNESS	10	Lowest dimming level
MAX_BRIGHTNESS	255	Full brightness
DEFAULT_BRIGHTNESS	128	Initial brightness on first boot
SAVE_DELAY	2000 ms	Delay before writing brightness to EEPROM

Building & Uploading

1. Open LedLamp-withTouchButton.ino in the Arduino IDE
2. Select your board (e.g. Arduino Nano, ATmega328P)
3. Select the correct COM port
4. Click Upload

License

This project is open source. Feel free to use and modify.