74*245 Motor Driver

H-Bridge Driver

Simple PWM Gen.

Handy Method Measuring RPM

Measuring RPM via Photo reflector

Introduction to Robotic

DC, Stepper,and Servo Motor

Microcontroller Tutorial

Computer Interface
Tutorial
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Basic LEGO Robot

by Pololu

LEGO is famous for its construction blocks, and it has lately been introducing many robot-themed sets. In this project, we demonstrate how you can use the Pololu micro dual serial motor controller to control a simple LEGO robot with a BASIC Stamp.

The BASIC Stamp from Parallax is a popular introductory miniature computer for learning the basics of electronics and computer programming. By themsleves, however, the BASIC Stamps cannot control motors, which are crucial to robotics and many other projects that require motion. LEGO is famous for its construction blocks, and it has lately been introducing many robot-themed sets. In this project, we demonstrate how you can use the Pololu micro dual serial motor controller to control a simple LEGO robot with a BASIC Stamp.

In its initial configuration, this robot behaves very similarly to the obstacle-avoiding robot from project 1: this robot drives forward until it hits an obstacle; when it does, it backs up, turns, and resumes its forward motion. In future projects, we will use this project as a foundation for more complex and interesting robots.

Because the details of the mechanical design are not particularly interesting, we will not cover the assembly of the LEGO chassis. Instead, we will focus on how to use the micro motor controller with the BASIC Stamp II. This sample project should, therefore, serve as a reference for anyone wanting to use a BASIC Stamp to control a small, differential-drive robot (a type of robot, which, like a bulldozer or tank, has independent drive wheels or treads on its two sides).

2. Materials and Tools
Here are the essential parts you will need if you want to build a similar robot. Except for the LEGO chassis, these items are available either from Pololu or from most electronic component distributors.

• Pololu micro dual serial motor controller
• BASIC Stamp II from Parallax
• Small, differential-drive chassis
• Two long-lever, snap-action switches for use as bumper switches
• Small solderless breadboard
• Two 10k resistors for use as pull-ups for the bumper switches
• 9V battery and battery snap
• Hook-up wire
• Power switch

3. Hardware Construction
Although we do not wish to dwell on the mechanical aspects of this project, the LEGO motor is worth mentioning. Within the compact housing are both a small motor and a very efficient gearbox. The motor is fairly expensive, but you'll immediately appreciate how much more quietly it runs than cheaper gearboxes. Because the motor draws only approximatly 100 mA, it is perfect for use with our micro motor controller.

To use the LEGO motors in you own project, you need to get leads that you can connect to your own electronics. One possibility is to cut a regular LEGO cable in half and solder on male header pins onto the cut wires. This will give you the two necessary connectors at the expense of one LEGO cable.

We built the electronics on a small solderless breadboard. As you can see from the close-up picture to the right, there isn't much to the circuit. The only components other than the BASIC Stamp II and the motor controller are the two pull-up resistors for the bumper switches. The schematic diagram for this circuit is shown below.

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