Researchers at the University of California, Los Angeles (UCLA) have developed PhoneBot, a small humanoid robot that uses an ordinary Android smartphone to process information about its surroundings and help control its movements. The project aims to make robotics more affordable and accessible to students, researchers, and hobbyists. The robot costs approximately $400 to build, excluding the smartphone.

PhoneBot stands about 19 inches tall and weighs roughly four pounds. Despite its compact size, it has demonstrated several capabilities, including walking on flat surfaces, following a person, and recovering after falling forward. Rather than relying on expensive cameras and specialized computing hardware, the robot uses a smartphone mounted on its torso. The phone’s camera helps identify and track people, while its built-in sensors provide information about movement and orientation. It also processes movement instructions and transmits them over Wi-Fi to a small computer responsible for controlling the robot’s 13 motors.

The research team tested the system with four Android smartphones, including the Honor 9, released in 2017, as well as newer budget devices from Motorola and Samsung. All four phones supported the essential functions. However, the Honor 9 could not run the mapping feature because it lacked the necessary Google services. These results suggest that even older smartphones can provide sufficient computing capabilities for certain robotics applications.

PhoneBot still has important limitations. It has no arms, can walk only on flat surfaces, and cannot carry substantial loads because of its relatively inexpensive motors. Researchers plan to improve its ability to navigate uneven terrain, add lightweight arms, and move more voice-processing tasks directly onto the smartphone.

The project builds on earlier smartphone-powered robotics efforts, including Intel’s wheeled OpenBot platform. However, reliable two-legged movement presents additional challenges, particularly maintaining balance. According to the research paper, the team improved walking behavior by training the software with mirrored movement examples, helping the robot distribute work more evenly between its legs.

PhoneBot is an open-source research project rather than a competitor to advanced commercial humanoid robots. Its main contribution is demonstrating how readily available smartphones can reduce the cost and complexity of experimenting with robotics.