Introducing the Updated XR1 and the New XJ-5: A New Class of Hobby Robots

The XJ-5 robot platform, available at Robots Builder, stands out for its user-friendly design, emphasizing accessibility and ease of assembly. Designed to make robotics more approachable, the XJ-5 is meticulously engineered for easy 3D printing and assembly with standard parts like servos and bearings.

Our goal is to simplify the building process so that enthusiasts and robot hobbyists of all skill levels can engage in constructing their own robots. We've invested time in perfecting the design, ensuring that users can quickly move on to the exciting tasks of programming and teaching their robots using Synthiam ARC. The XJ-5 is highly customizable, featuring a variety of hands and heads to allow personalization of each creation. To encourage a collaborative and open community, we're proud to announce that the XJ-5 is entirely open source, inviting users to contribute, modify, and share their innovations globally. Get ready to embark on a journey of creativity and exploration with the XJ-5!

For more information, check out Robots Builder.

As a creator of the XJ-5 and our other XR series, I will be leveraging the Synthiam ARC platform for robot control, and I hope others here will join me in developing an ARC project to support the XJ-5 robot. As of January 9th, 2024, we have started posting files for 3D printing. Meanwhile, we are developing documentation and the above website, so please check back regularly.

My goal is to have a walking, talking, listening, and seeing robot the size of a small child using ARC and its various skills. As I progress, I will be sharing more about my efforts here.

Now, let's dive into the project focusing on the new and improved XR1, the XJ-5, which I have been designing and building over the past year.

As a young enthusiast, I loved the movie Short Circuit and fell in love with the Johnny 5 robot, inspiring me to create a similar robot. It was not designed to replicate the original Johnny 5. About a year ago, DJ suggested preferring a robot with wheels or tracks over a bipedal robot due to the complexity of making them walk, a challenge I am familiar with from our XR2 project. But hey, that's another story.

Now, in May 2025, I've almost completed the assembly and will start implementing ARC and the AI brain I've been working on to support ARC. More updates will follow.

I have started building the torso from the hips up, as shown in the pictures below. The shoulders are not fully installed because I'm waiting for the correct screws to arrive. Please excuse the messy workbench.

To support the robot, I have designed a set of boards with ARC firmware that will connect to the onboard PC, which will be situated in the middle of the chest.

The above board will be mounted on the backplate between the two shoulder sockets and connected to the USB hub that will be connected to the PC. Two more USB cables, along with servo power, run down to the boards in each hand. The USB camera and headboard will be connected to the PC's other two USB ports. ARC will run headless on the Windows 11 Pro PC using RDP for remote connectivity. Additionally, there is an MPU connected to the main board that I plan to leverage with ARC.

I have added the shoulders and arms down to the wrists, and they appear to be strong and capable.

I decided to create a Johnny 5-style head for my build featuring two cameras. Here is the completed head. I have added six more servos to the build for the eye flaps, bringing the total count to 50 servos. It includes a directional mic array and ultrasonic radar for enhanced audio and visual capabilities. For sound, two speakers are mounted in the head with an audio amplifier.

I have also decided to add an option to the XR-1 to support a 5-inch touch display, as shown below.

The display will provide more options for operator interaction using ARC remote controls.

I have created both two and three-finger claw grippers and human-like hands, providing versatility in interaction for the XR-1.