Over-Engineered Breadboard Power Supply

This project is a compact, high-current breadboard power supply designed to deliver stable, monitored, and flexible power for advanced electronics prototyping.

The board accepts a wide input voltage range of 4.5–20 V and generates three regulated output rails, each capable of supplying up to 2.5 A:

Adjustable 4–20 V output

Fixed 5 V output

Fixed 3.3 V output

To achieve high efficiency and thermal stability, the design uses dual buck converters for the main rails and a low-noise LDO for logic power.

A key feature of this design is real-time current and voltage monitoring using an INA219 high-side current sensor with a 10 mΩ precision shunt resistor. The sensing network is routed using Kelvin connections to maintain measurement accuracy under high load conditions.

System control and data handling are managed by an ATtiny85 microcontroller, which drives an I²C OLED display to show live voltage and current information directly on the board.

Special attention is given to power integrity and PCB layout discipline:

• Clear separation between power and signal paths
• Wide copper pours for high-current handling
• Optimized thermal reliefs
• Hand-solderable SMD footprints
• The board is mechanically designed to integrate cleanly with standard solderless breadboards, while also providing terminal block outputs for higher-current connections.

Overall, this project demonstrates a robust, measurement-aware power supply architecture packaged into a breadboard-friendly form factor, bridging the gap between simple hobby power modules and professional lab equipment.