4-Digit Code Lock – DIY Solder Kit with Relay Output

**-- THIS PRODUCT CONTAINS 1 KIT PER PACK --**

This 4-digit code lock soldering kit is an excellent hands-on electronics project that provides a secure, programmable relay control system. With more than 3,000 possible combinations using nine push-button inputs, users can program a 4-digit security code to control a relay-based output device. A built-in LED provides state indication, and incorrect inputs reset the timer, enhancing the system’s security features.

Designed with protection against reverse polarity and a simple relay switch, this project is ideal for students, hobbyists, and tinkerers interested in digital logic, access control, or custom automation. The kit operates on 9–15V DC or 8–12V AC, and includes a powerful 5A/220V relay suitable for switching various low-voltage devices.

**Specifications**
- **Power Supply:** 9–15V DC or 8–12V AC
- **Code Combinations:** 3,000+ possible 4-digit entries
- **Input Options:** 9 pushbuttons (user-selectable)
- **Time Limit for Entry:** Approx. 5 seconds
- **Relay Output:** 5A / 220V
- **Current Draw (Idle):** ~0.0003 mA
- **Current Draw (Active):** ~40 mA
- **Protection:** Polarity-reversal secured
- **Indicator:** LED for state/status display

**Key Features**
- • More than 3,000 possible code combinations
- • Relay output for controlling low-voltage devices
- • LED indicator for clear visual feedback
- • Polarity-protected circuitry for safe assembly
- • Excellent educational soldering and logic kit

**-- THIS PRODUCT CONTAINS 1 KIT PER PACK --**