SBK RP1

SBK_RP1

Front                             Back

Open-source reverse polarity protection module for learning and embedded electronics projects.

SBK_RP1 is a compact, reusable hardware module that protects low-voltage DC electronic circuits against accidental reverse battery connections. Using a P-channel MOSFET ideal-diode topology, it provides reverse polarity protection with a much lower voltage drop than a conventional series diode. An integrated LED indicates when protected output power is available.

Designed for breadboards, prototypes, and educational projects, SBK_RP1 offers a simple way to improve the robustness and reliability of battery-powered embedded systems.

Features

• Input voltage: 2–12 VDC
• Maximum Load current: 2 A
• Maximum practical current depends on operating voltage, ambient temperature, PCB cooling, and allowable temperature rise.
• Reverse polarity protection using a P-channel MOSFET
• Very low forward voltage drop
• Protected output power status LED
• Breadboard-friendly 2.54 mm pin header
• Optimized for low-cost assembly using JLCPCB Basic components

Pinout

Typical Application

Battery
   │
SBK_RP1
   │
SBK_SP1 (optional)
   │
Embedded System

SBK_RP1 is installed between the power source and the electronic circuit. During normal operation it introduces only a very small voltage drop. If the supply is accidentally connected in reverse, the module automatically blocks current, protecting the downstream electronics.

Operation

1. Connect the power source to VIN and GND.
2. With correct polarity, the MOSFET turns on and powers VOUT.
3. The voltage drop across the module remains very low.
4. If the supply polarity is reversed, the MOSFET blocks sustained current flow to the protected output.
5. Current flow is blocked, protecting the connected circuit.
6. The output status LED indicates when protected power is present at VOUT.

Applications

Microcontroller platforms

• Arduino
• ESP32
• RP2040
• ATtiny
• STM32

Example applications

• Battery-powered embedded systems
• Portable instruments
• Sensors
• Educational electronics projects
• Custom electronic devices

Notes

• Designed for low-voltage DC electronic circuits.
• Protects against accidental reverse polarity connections.
• Does not provide over-current or over-voltage protection.
• The output status LED indicates the presence of protected output voltage; it is not a reverse polarity indicator.

Getting Started

This project is fully open-source hardware. You can:

• Build your own module using the provided KiCad design files.
• Modify the design to suit your application.
• Manufacture your own boards.

Assembled Modules

If you prefer a ready-to-use module, fully assembled SBK_SP1 boards may be available in small batches on demand.

For availability, pricing, or quantity inquiries, contact:

📧 SmartBuildsKits@gmail.com

These modules are intended for hobbyists, educators, prototypes, and small-scale projects. Availability depends on component stock and production capacity.

Related Projects

• SBK_FET1 – N-Channel/P-Channel FET modules
• SBK_SP1 – Soft Power Switch Module
• MémoBot – Educational memory game built using SBK_SP1 and SBK_RP1

Contributing

Suggestions, bug reports, and improvements are welcome.

To report a problem or suggest an improvement, open an Issue. Pull Requests are also welcome for corrections, documentation improvements, and design changes that make the project easier to understand or build.

Support the Project

If this project is useful for learning, teaching, or prototyping, you can support its continued development.

Donations help fund prototype hardware, documentation, educational resources, and future open-source projects.

❤️ Support the project through PayPal

Thank you for supporting open-source educational hardware.

License

This project is released as open-source hardware under the CERN Open Hardware Licence Version 2 - Permissive (CERN-OHL-P v2).

You are free to study, modify, manufacture, and distribute this design, provided the terms of the license are respected.

See the LICENSE file for the full license text.

Design Files

This project was designed using KiCad 10.

• KiCad hardware files
• Bill of materials
• SBK_RP1 datasheet