Researchers Transform Old Android Phones into Humanoid Robot Brains

Researchers at the University of California, Los Angeles (UCLA) have discovered a new use for older Android smartphones by repurposing them as the central brain for a small humanoid robot named PhoneBot. This prototype, detailed in a preprint on arXiv, challenges the assumption that robotics research needs costly computer equipment. The robot, which stands about 48 centimeters tall, can walk, follow a person, and stand up on its own. The cost of the robot's hardware—excluding the smartphone—is around $400, a relatively low price in the robotics field, where sensors and processors can quickly drive up expenses. The smartphone is mounted at the robot's torso and provides essential functions such as a camera, motion sensors, and computing power. An Android app runs the algorithm that controls the robot's movements, which were first trained in a simulated environment. These commands are then sent over Wi-Fi to a small electronic board that controls the robot's 13 motors. The researchers tested PhoneBot using four different Android phones, including older and less expensive models. While the phone is sufficient to manage the robot’s movement, it cannot handle all functions. For example, PhoneBot still needs an external computer to support conversation features. The concept of using a smartphone as a robot’s brain is not entirely new. A similar project called OpenBot used a phone mounted on a small rolling robot that cost about $50. PhoneBot builds on this idea by applying it to humanoid robots. The primary goal of the project is educational, as many students, teachers, and hobbyists already have smartphones that can provide a camera, accelerometers, and computing power without needing to buy these components separately. The PhoneBot project is open source, meaning its design and software are freely available to the public. This approach aims to make it easier for others to reproduce and experiment with the robot. By using common technology, the researchers hope to lower the barriers to entry for robotics education and innovation.