Learning Arduino might be a good starting point, since they are easy and popular. You'll probably need to learn C, since Arduinos (or the controllers on the Arduino boards) are programmed in C or assembly.

There is a cost for equipment and parts when working with hardware.

Creating effects in the physical world with your code feels awesome. Learning and building physical tech is just awesome all around.

See this thread for pointers: https://news.ycombinator.com/item?id=21871026