This module enables you to easily control up to 7 loads over an I2C or SPI interface, while needing minimal resources from your CPU. It can also drive a unipolar stepper motor.
We are using this module to switch some small lightbulbs, and to control a stepper motor. Driving a stepper motor uses 4 outputs, so it is still possible to switch 3 other loads.
Possible uses:
- DIY CNC machine
- Driving high-power LEDs or incandescant bulbs
- Driving solenoids
- Driving standard motors

The software takes care of driving the stepper motor, you only have to specify how many steps to take, and the delay between steps.

The board is equipped with a 3-pin jumper/header, to select a power source for the FET outputs. one option is to draw power from the I2C connectors, and an other option is to connect a high-power source.

The PCB is equipped with two I2C connectors, so daisychaining multiple I2C modules is an option.
This allows you to control the FETs with only 2 data lines (SDA and SCL). This makes it possible to chain multiple modules without the need for more IO pins!
The board can be used with all microcontrollers, such as the Atmel AVR, Arduino/Freeduino boards, Microchip PIC, etcetera. Other computers/boards with an SPI interface (such as the Raspberry Pi) should also be able to control this module.
The module comes with all connectors pre-soldered:
One male 1x4 I2C connector, and 1 female I2C connector, (one for input, and one for daisy-chaining).
7 2-pin load-connectors
1 3-pin power supply jumper/connector

Datasheets:
Documentation for the complete PCB