This PCBA features piezo/vibration tap trigger, full-color RGB illumination, ultra-low power consumption and Type‑C USB charging, ready for mass SMT production and compatible with 3.7V lithium battery.
Power supply: 3.7V lithium battery + 5V Type‑C USB charging with red LED charging indicator.

I. Operation Instructions

• Long press for 3 seconds: Power ON / OFF
• Tap lamp housing: Cycle lighting modes (Solid Single Color → Mixed Color → RGB Gradient → Breathing → Power Off)
• Short press the button: 3-level brightness adjustment (50% / 70% / 100%)
• Lighting effects: Full RGB spectrum including solid fixed color, running water, breathing, gradual color shift and strobe flash
• Auto standby: Automatic power-off after 2 hours of inactivity with ultra-low standby power
• Protection: Reverse charging protection, overcharge/overdischarge protection and short-circuit protection

II. Main Control MCU

Available models: SC8P1711 / HT66F0185 / XL32F001 in SOP‑8 package; cost-effective domestic MCU with 4-channel PWM output.

Responsibilities: Tap vibration signal acquisition, PWM dimming output, logic control, scheduled sleep and charging management.

1. Three mainstream tap sensing solutions

1. Piezoelectric ceramic disc (preferred): Affixed inside silicone casing; generates induced voltage upon tapping, high sensitivity & low cost for soft rubber housing.
2. SMD vibration switch SW‑520D: Mechanical trigger dedicated for hard-shell tap lights with strong anti-interference capability.
3. Capacitive sensing: Dual-mode of touch + tap for high-end products.

2. Power & Charging Circuit

• Charging IC: TP4056 / YL4056H, 5V input, supports 500~1000mAh lithium cells with three-stage charging algorithm.
• LDO regulator: AMS1117‑3.3V to supply stable voltage for MCU and sensors.
• Battery protection IC: DW01 for overcharge, overdischarge, overcurrent and short-circuit safeguard.

3. LED Driver & Light Source

• LED options: 3~6pcs of SMD 5050 RGB or 2835 warm-white LEDs.
• Driving solution: NPN transistor or direct MCU PWM drive without additional constant-current IC.
• Current-limiting resistor: 150~220Ω per channel to limit working current at 20~30mA for extended LED lifespan.

4. Peripheral Components

• 1 tactile button for power switch and brightness regulation
• Type‑C socket for charging input
• SMD resistors & capacitors in 0603 package for compact PCB layout
• Optional IR receiver for remote power on/off and color adjustment

III. Working Principle

• Standby status: MCU enters sleep mode with total system power consumption below 10μA for long battery life.
• Trigger process: Tap the shell → piezo/vibration sensor outputs trigger signal → MCU wakes up from sleep.
• Dimming control: MCU outputs three-channel R/G/B PWM signals; varying duty cycle realizes adjustment on color, brightness and working modes.
• Charging process: Red indicator lights up when TP4056 starts charging the lithium battery via USB; charging automatically stops once fully charged.
• Auto shutdown: MCU cuts off power and goes into sleep after 2 hours without operation.

IV. Standard PCB Mass Production Specifications

• Material: FR‑4 single-sided or double-sided PCB
• Standard dimension: 45×22mm (regular size for silicone tap night lights, customizable available)
• Production process: SMT + through-hole assembly with 0603 components; mass production yield over 98%
• Electrical specs: 3.7V lithium battery, 5V/1A charging input