Making Friends – A BEAM Robot Pet

A little spinning top that looks like a satellite in orbit. Click here to build this bot.
A little spinning top that looks like a satellite in orbit.
Click here to build this bot.

BEAM is field of robotics pioneered by Mark Tilden. BEAM robots often use deceptively simple designs with a minimalist aesthetic can often result in complex analog behavior. Keep an eye open for a post about Huey, one of Mark’s latest robots, later today.

You can try your own hand at building a very simple BEAM robot pet with this Solar Trimet Project.

A Trimet is a simple BEAM spinner with three symmetrically-balanced components. It incorporates a common BEAM solar power management circuit called a voltage-triggered solar engine. It is basically comprised of the solar engine, a DC motor scavenged from a cassette player, a solar cell, and three capacitors that store the energy from the cell (and also act as the main structure of the “bot”).

Scavenge your own parts or pick up a Make Robot Bundle.


This week marks the official launch of Make: Volume 39 — Robotics, which drops on newsstands the 27th. Be sure to grab a copy at a retailer near you, or subscribe online right now and never miss another issue.

We are celebrating with five days of robot-related articles, pictures, videos, reviews and projects. Tune into this space for Robot Week!

Our next theme week will be wearable electronics. Send us your tips or contributions before it gets here by dropping a line to


1 thought on “Making Friends – A BEAM Robot Pet

  1. Blue Coaster33 says:

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Andrew Terranova is an electrical engineer, writer and author of How Things Are Made: From Automobiles to Zippers. Andrew is also an electronics and robotics enthusiast and has created and curated robotics exhibits for the Children's Museum of Somerset County, NJ and taught robotics classes for the Kaleidoscope Enrichment in Blairstown, NJ and for a public primary school. Andrew is always looking for ways to engage makers and educators.

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