Building my humanoid robot

A homemade humanoid robot, built from printed plastic parts and motors ordered off AliExpress, is now picking up bottles and dropping them into a basket, guided entirely by artificial intelligence.

That's the quiet achievement at the heart of one engineer's 90-day project, which began in December 2025. Starting from an open-source design called K-Bot, the builder assembled a robotic arm, wired up six motors over a single communication bus, and taught the arm to move using a PS4 controller.

The real ambition, though, was training a vision-language-action model to take over. By recording hundreds of demonstrations and fine-tuning an AI called SmolVLA, the arm learned to read a text instruction, see through three cameras, and act.

What's emerging is something the builder calls a "physical API," a feedback loop where the robot learns continuously from real-world use. Two arms, aluminum parts, and a miniature puppet controller are all on the horizon.