Approx construction cost for Parts 1 (Oct 2004) and 2 (Nov 2004): US$10.80 (power switching board), US$16.20 (Processor board), US$7.20 (Sensors - two required), and US$14.40 (Effects board)

Approx construction cost for Part 3 (Dec 2004): US$10 (bumper sensor), US$6 (light sensor), US$20 (ultrasonic sensor), US$15 (distribution board)

Approx construction cost for Part 5 (Feb 2005): US$6 (light sensor and probe), US$22 (distribution board)

Approx construction cost for Part 7 (Apr 2005): US$18 (Sound and light board)

A PIC-based mobile buggy with various sensors and actuators. Suitable for tailoring to your needs!

In this short series of articles we describe the construction of a mobile hobby robot, Smart Kart, and then proceed to variously equip it with a collection of sensors and actuators, each capable of a variety of tasks, some serious and some amusing. There are also discussions about the controlling software and how you can modify it to suit your own needs.

The basic Smart Kart has a pair of infrared sensors and a range of “bells and whistles” (actually, l.e.d.s and a bleeper) to give it character. They also indicate what it is going to do next.

Smart Kart comprises three decks (see photographs) joined vertically by spacer tubes. Construction is very simple, requiring few tools and does not involve highprecision engineering.

The system of propulsion is a favourite one for small robots. The two drive wheels are separately driven by low-voltage d.c. electric motors. They each have a 1:288 gearbox to reduce the motor speed to a reasonable rate. The prototype has forward and reverse speeds of about 10cm/s, which is ideal for indoor operations. Balance is maintained by a castor at the rear of the vehicle.

In the basic Smart Kart, the motors are either switched off or run at full speed. Later in the series we introduce motor speed control when it suits the application. The simple on-off control used in the first application gives nine possible actions, that are combinations of off, forward and reverse for each motor.