Darlinton Array

Darlington Arrays are an incredibly cheap, safe and easy way to boost output from digital pins.

Darlinton Arrays are a great way to amplify the signal of a GPIO and Arduino IO pins, which are generally only enough to run a logic circuit and generally max out when lighting an LED.

They are fairly simple in design and consist of an array of transistors, in this case 8, with diode protection (incredibly important when using with things like relays and solenoids).

Related Services
The RPi Gpio service provides nodes that allow you to set and read the state of the pins of a Raspberry Pi. Note: This service must be run with root privileges.