UCLA turns an old smartphone into the brain of a walking robot - Big Tech and the digital economy

Researchers at UCLA’s RoMeLa laboratory have developed PhoneBot, a 48.3-centimeter bipedal robot that uses a smartphone’s sensors, processor and camera to maintain balance, process movement commands and interpret its surroundings.

Researchers at the University of California, Los Angeles (UCLA) have given an unused smartphone a new role: controlling a small walking robot. Called PhoneBot, the prototype stands 48.3 centimeters tall and weighs 1.8 kilograms, including the phone mounted in its torso.

The project was developed by RoMeLa, UCLA’s robotics laboratory, and described in a study published on arXiv on October 6, 2026. PhoneBot has 13 motorized joints, with the smartphone acting as an important part of its control system rather than serving merely as a display or communications device.

The phone’s motion sensors measure the robot’s inclination, while its processor calculates movement commands. Its camera can interpret what is in front of the robot, and instructions are sent over Wi-Fi to an electronic board connected to the motors. Users can also send movement commands, separating the robot’s balance control from decisions about where it should move.

Walking on two legs required more than simply attaching motors to a frame. PhoneBot must coordinate its joints, distribute its weight and prevent one step from destabilizing the next. The researchers trained its control system in simulation using reinforcement learning, which improves behavior through rewards and penalties. They also introduced a mechanism to encourage symmetrical movement after observing that the robot tended to favor one leg.

Tests with the physical prototype showed that PhoneBot could walk and stand up after falling onto its front. The team also demonstrated that the robot could use the phone’s camera to detect a person and turn its torso toward them. That demonstration does not mean it can autonomously follow someone through any environment. The robot includes conversational functions, although voice recognition and language-model processing run on an external computer.

The team tested several Android phones, including the Honor 9, a model released in 2017, along with three newer budget devices. According to the study, the Honor 9 was able to perform the main evaluated functions. However, it could not provide environment mapping through ARCore because the necessary Google services were unavailable on that device in the United States. The researchers do not attribute every physical demonstration to that specific phone.

The robot’s body costs about $400 in components, excluding the smartphone. Much of that cost comes from its 13 joint motors. The researchers have shared design files and documentation to support replication, but the license restricts commercial use. As a result, the project is presented as an open platform without meeting the usual criteria for open-source hardware, and it has not been verified that all required software is publicly available.

Using a smartphone as a robot’s control center is not entirely new. Intel Labs presented OpenBot in 2021, a project that turned a phone into the controller for a small wheeled vehicle whose body could be built for about $50. PhoneBot applies a similar idea to a bipedal machine, where balance creates additional technical challenges.

For now, PhoneBot is designed for flat surfaces and lacks arms, so it cannot handle objects or navigate every type of terrain. Its developers want to add lightweight arms and test the robot on more demanding surfaces. The prototype nevertheless demonstrates that an older smartphone can provide the sensing and processing needed to make a small two-legged robot walk.

Sources: Xataka.