Meet the Dimebots: Self-Contained Micro-bots the Size of a Dime

Chris Stemple built these tiny bots with a repurposed pager motor, an ATtiny1614, a LiPo battery, and o-rings.

James Lewis
16 days ago β€’ Robotics

When you think of a robot, you might envision a large, complex contraption. However, Dr. Chris Stemple's ingenious Dimebots are a different construction. These micro-bots, about the size of a dime, are surprisingly simple and easy to build with readily available parts.

Stemple crafted the clever little micro-robots with a tiny motor, LiPo battery, proximity sensor, and a microcontroller. They weigh only five grams and are about the same size as a US dime (about 18 millimeters), hence the name Dimebots.

A Microchip ATtiny1614 microcontroller runs the robot. Stemple initially considered the Microchip ATmega328P, the same eight-bit microcontroller used in the Arduino Uno and Nano boards. However, the ATtiny1614's SOIC package offers easier soldering and a single-pin Unified Program and Debug Interface (UPDI), which saves space on the custom printed circuit board and reduces the build cost by not requiring a specialized programmer. For example, you can create a UPDI programmer with a USB-to-serial cable and a single (10 kilohm) resistor.

An optical sensor positioned on Dimebot's front provides "vision." It is a Vishay VCNL4040 proximity and light sensor. These infrared-based sensors, with their built-in signal conditioning and I2C communication, seamlessly integrate into projects like Dimebot. They can detect ambient light and, more crucially for a robot, determine its proximity to a wall or object, enabling the bot to navigate around obstacles.

A 30 milliamp-hour battery provides energy for Dimebot's electronics and a 4 x 8-millimeter motor. Stemple repurposed this mini motor from a pager's vibration module. According to the motor's datasheet and the battery's capacity, Dimebot's runtime could reach up to an hour. The motor's 70-millimeter shaft attaches to the drive wheels.

The drive wheels have two major components: a hub and a tire. Stemple 3D-printed a hub that attaches to the motor's shaft and a "tire" made from 005-sized o-rings. The freewheels, made from an off-the-shelf ball bearing, also use the o-rings as tires. Stemple lightly sanded the o-rings to increase their traction.

You can download the MIT-licensed Eagle design files, 3D-printable parts, and sample Arduino code from the Dimebots GitHub repository. This project description provides additional detail on why Stemple chose specific parts.

James Lewis
Electronics enthusiast, Bald Engineer, and freelance content creator. AddOhms on YouTube. KN6FGY.
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