The Pi Supply Octopus 5mm LED light brick (ambient light sensor) extension can be connected to Arduino boards. The digital pin (LOW on, HIGH off) is used to control it. The brightness of LED can be controlled via PWM output.
There are five colors for you to choose from
What are Octopus Electronic Bricks?
Pi Supply Octopus Electronic Bricks can be used to build electronics projects just as easy as piling bricks. You can also connect Arduino compatible boards easily with various digital, analog and I2C/Uart interfaces. The breadboardless connections let you connect expansion modules like potentiometers, sensors, relays, servos, buttons in a plug and play way.