Adafruit Inductive Charging Set - 5V @ 500mA max

The squarish board with two chips is the transmitter, powered with 9V. The longer board serves as the output, connecting to the part of your project that needs power. This basic charger set provides a 5V DC output when the input side is powered with 9V to 12V DC.

Inductive charging allows for wireless power transfer. It functions by splitting a power transformer into two parts. An AC waveform generated in one part couples with the second, similar to how electric toothbrushes recharge. This setup delivers enough power for low-demand projects, drawing up to 500mA when the coils are 2 to 3 mm apart. For lower current needs like 100mA, they can be spaced up to 7 mm apart. With only a 10mA draw, the coils can span a half-inch gap.

Non-ferrous and non-conductive materials such as air, wood, leather, plastic, paper, or glass can separate the coils without affecting efficiency, provided they remain co-axial. Although the system is relatively inefficient with about 40% energy transfer, it suffices for low-powered or charging applications. A power draw of 5V 100mA requires approximately 150mA from the input end, while the system maintains around 70mA when inactive.

Though simple, these modules can be customized. Advanced users may alter the output voltage by adjusting the feedback resistor divider on the output side, using 0603 SMT resistors to yield a 3.3V output.