PlatformIO - Next-generation IDE for IoT
codebender - The Largest Arduino Playground In The World. Create, share and run your code anywhere.
ArduBlock - ArduBlock is a graphical programming language plugin specifically made for Arduino circuits and controllers.
Raspberry Pi - The Raspberry Pi is a tiny and affordable computer that you can use to learn programming through fun, practical projects. Join the global Raspberry Pi community.
Modkit - Modkit is an open-source programming platform that allows programmers with a variety of backgrounds to share their creations and learn from each other and is allowing programmers to make beautiful software.
Arduino - Build your own electronics