The servo is a controllable motor that can swing back and forth or be turned to a specific position. Attach a flag to the arm to make it wave back and forth. There are even a few littleBits accessories made just for the servo (like the mechanical arm). *Bit not compatible with plastic accessories in Droid Inventor Kit
If you're looking to track your collection or decide on your next bit, this list is a good place to start. Fill in the number of each bit you already own to get started. You can also see what bits are included in the most popular kits including Gadgets & Gizmos, Rule Your Room and the Synth Kit. Tip: try the grouping feature to change the view to group items by their inclusion in a kit. Fun fact: it costs $1,289.63 (US Dollars) to buy one of every bit on this list.