Domestic, hobby and competition robots are the best-suited categories of robots you can make at home. These robots are not complex, and they do not take a lot of time to complete compared to space robots or military robots.
An example of a hobby or competition robot is a sumo-bot. Sumo-bots are autonomous, remote-controlled robots that compete in head-to-head matches similar to human sumo matches. With just a few micro-controllers, wheels, gears and software, you can easily build a sumo bot. This is in stark contrast to the materials, expertise and labor needed to build a complex military robot such as a drone.
Another hobby robot you can make at home is a racing robot. This type of robot is much like an autonomous radio-controlled toy car. Hence, a racing robot is capable of navigating a set-out route without human intervention. However, such a robot may feature both autonomous navigation and human assisted navigation.
In the domestic category, a vacuum cleaner robot is good home project. The materials needed to make such a robot, such as an Arduino board, a chassis made out of cardboard and a turbine from a computer cooling unit, are inexpensive and relatively easy to find.