Before the explosive growth of smart phones in the late 2000s, there was still a reasonable demand for pocket computers that could complete relatively simple computing tasks. Palm pilots and other PDAs (personal digital assistants) were all the rage in the 1990s and early 2000s, although for the cutting-edge technology of that era, the prices of many such devices reached astronomical figures. This Arduino based PDA dates back to that era, although there is a more accessible parts list.
Based on arudino nano and OLED screens, the product has five functions required by PDA: calculator, stopwatch, game, phonebook and calendar. Since all these components are installed on such a small microcontroller, memory quickly becomes an issue when using the default library. [danko] uses its own custom libraries to take full advantage of all available memory on the GitHub page of the project. This version also includes a custom PCB to maintain the pocket size of the entire handheld computer.
Other features are also included in this small build, such as a breakthrough game that can be played with a potentiometer. This is an impressive build that makes full use of the functions of the microcontroller. If you like a project where the microcontroller is used like a PC, please take a look at this Arduino build with its own command line interface.