7 months ago

GeRo, the German robot

A real humanoid robot powered by a Raspberry Pi, the German Robot (GeRo) is like a more advanced Rapiro

“I’ve been fascinated by humanoid robots for a long time,” Johannes Jaegers, the creator of GeRo, tells us. “I finally decided to make one myself when I saw the Rapiro project on Kickstarter.”

From this fascination comes GeRo, the German Robot. It’s a walking, talking robo‑project running on a Raspberry Pi. GeRo is fully programmable by the user and can even be controlled remotely over the network from any web browser. The camera and microphone also stream to the webpage connected to it.

For this type of complex robot, a Raspberry Pi is not always used, with some makers using Arduino controllers to do the job. “I preferred a computer over an Arduino,” Johannes explains. “Using a computer like the Pi allows for many more features like the camera and microphone connection, ROS integration, sensor data evaluation, reactions, and so on. I chose the Raspberry Pi because it was cheap and it had a great online community which supports a lot of functions like software PWM which is needed to connect the 17 servos.”

ROS is the Robot Operating System, an open-source OS specifically for creating and programming robots. It’s used in the GeRo, making it fairly unusual among Raspberry Pi robots, which usually just work with Raspbian.

Robot prototypes

It took Johannes about two years on and off to build the robot. It consists of a metal skeleton and 3D-printed parts, along with a custom PCB to power the Raspberry Pi and connect to the 17 individual servos and the battery. There is a full list of parts online you can read, which gets a little extensive when you get down to the nitty-gritty.

“In general it works quite well,” states Johannes. “However to do anything with the robot, the movements and the text for speech have to be defined. I wrote software to make the positioning of each servo as easy as moving a slider; however, it still takes some work and time to perform, especially for the walking sequence. The robot has no servos to turn the legs around, so it’s limited to walking in a straight line for now, and cannot easily turn. However, it can stand up from any position and speak any sentence in different languages.”

You can 3D print different chassis for the Gero

Johannes has recently made the process of building the robot, along with some of the materials, accessible online from german-robot.com, and he reckons you can build the robot for less than 500 euros (about £430/$530). It’s not overly complex, but Johannes reckons it’s best to have some level of understanding of robot hardware and software and how they can interact, along with some soldering experience to boot. “I really enjoyed working with the Raspberry Pi, especially because it supports ROS and made it so cheap and easy to get direct hardware access from Python and C and thus build complex systems.”