If you've just stepped into the world of robotics and are looking to make your first robots, SBCs provide the platform. While Raspberry Pi is a great choice for this, in a lot of robotic projects, a microcontroller board will be just sufficient. For example, if you've a Raspberry Pi Pico, you can build a robotic head that displays emotions.

You can make a customizable robotic head with Raspberry Pi Pico

In a robotic project called rEmotion, Andrei Gramakov made a robotic head with a Raspberry Pi Pico and has also put up a guide that helps you build your own. In addition to the essential components, all you need to have is basic electronics and 3D printing knowledge to build one, as the creator designed the project to be "accessible and easy-to-develop."

What's great about this robotic project is that not only can you build one by yourself but also be able to customize it to add more features or add modifications to the behavior. To put this into perspective, on the project's GitHub resource page, there are mentions of as many as eight different emotions, but you can add more. As stated by Gramakov on GitHub:

rEmotion is a hardware module with a robotic application in mind. The module represents a head with a display and a camera alowing a robot to see the environment and express facial emotions.

As described by the creator, the robotic head as it exists isn't super powerful but you can make it like one if you have the skills. And the best part is that, since the project is based on the Raspberry Pi Pico, it's super cheap. The recently released Raspberry Pi Pico 2 costs only $5. The complete details of the project can be found on the Hackaday website.