A Quick Guide to Building Bots: Rapid Prototyping Techniques for the Novice Robot Hobbyist

Don Wilcher

Don Wilcher is an electrical engineer, robotics expert, author and adjunct professor whose main goal is to technically enrich lives. His web site focuses on sci-tech robot projects for families. Editor.

Building robots is as much an art as a science. Various techniques are used in constructing autonomous mobile robots and intelligent walkers. The selection of a technique is usually based on the availability of construction materials.

I like to think of prototyping as the technique of validating an idea using a physical proof of concept (POC) model. Another term used to describe the process of building models is Rapid Prototyping. Stereolithography (SLA) machines, and 3D printers help accomplish the task of building a model within a short amount of time. To build a rapid prototyping robot requires materials that will allow the amateur roboticist to implement a design quickly without the need to machine many individual parts.

Toys have become a popular source of prototyping materials that assist the amateur roboticist in building robots within a short amount of time. The LEGO Mindstorms Robotics Invention System (RIS) has become an important amateur roboticist choice of rapid prototyping material. This product provides an important source of various plastic mechanical parts that can be used to quickly implement an autonomous robot design. The pre-fit studs that are molded on all of the plastic bricks and plates make building robots as easy as a snap.

Figure 1 shows a Beetle-Bot built for a robotics book I wrote for McGraw-Hill. The Erector set has also been used to rapidly build robots because of its screw and nut attachment method that uses a variety of pre-machined parts.

Figure 1. Beetle Bot Robot using the LEGO Mindstorms RIS kit. From "LEGO Mindstorms Mechatronics" by Don Wilcher, McGraw-Hill (2004).

The Robo-Rig shown in Fig. 2 illustrates the versatility of using an Erector set for rapid prototyping robot construction projects.

Figure 2. Robo-Rig built with Erector set parts. From "LEGO Mindstorms Mechatronics" by Don Wilcher, McGraw-Hill (2004).

The ROBOTIX kit is a unique motorized construction set consisting of plastic parts that use an octagon interlocking system for mechanical assembly. The finished product looks quite futuristic and is also very sturdy. Figure 3 shows a ROBOTIX mobile platform.

Figure 3. A ROBOTIX-based Mobile Robot.

Working with electronics hardware

The electronics hardware is critical to the overall success of an intelligent, autonomous robot. If you are new to robotics, Erik Zoltan suggests in "Wireless robotics: Fast robot prototyping" that you have two options:

1. Purchase several of the toy-oriented robotic sets that are available for children and adults. This is strongly recommended for anyone trying to learn the field. Some serious robotic projects have been prototyped using toy robotic systems.

2. Learn some basic electronics and how to use a soldering iron.

In addition to Erik's suggestions for working with electronics hardware, I recommend the following:

1. It's best to use a solderless breadboard learning system like Radio Shack's Electronics Learning Lab developed by Forrest Mims. The Learning Lab comes complete with electronic parts, pre-cut jumper wires, a sturdy solderless breadboard system and two workbooks.

2. Learn how to program a microcontroller using a Basic Stamp, LEGO RCX (programmable brick), Handy Cricket Embedded Controller or a PICAXE system. These embedded controllers provide a quick and easy alternative way of programming the brains for your planned robot.

3. Keep a well stocked junk box of electronic parts and old consumer electronic printed circuit boards. Consumer circuit boards can be recycled for electronic parts, connectors, switches, motors, and other devices that can be used to prototype robots.

4. Finally, get a good software circuit simulation program like MicroCap 8 to validate circuit designs prior to building them on a solderless breadboard.

Virtual Software Development and Test Tools

The result of these electronics hardware suggestions is rapid robot construction. An ample supply of electronic parts and materials will expedite and simplify building the robot's electronic brain and support circuits. Also, a virtual robot simulation program will allow mechanical design concepts to be tested on a notebook or desktop computer prior to the actual physical build of the machine. A freeware program called Modulobe (Fig. 4) can assist in the virtual build and testing of a mechanical machine.

Figure 4.The author's virtual robo creature “OctoBot” built from the Modulobe software.

The ability to check out the logic and controls before committing the software code to an autonomous robot using a flowchart (Fig. 5) can easily be realized with a freeware program call Program Edit . This freeware package automatically generates a BASIC programming language that can be downloaded and executed on a target PICAXE based microcontroller.

Figure 5. Program Edit software generated flowchart for testing a piezoelectric buzzer.

Finally, The Handy Cricket embedded controller (Fig. 6) has an online virtual simulator for pre-validation of its Cricket Logo programming language. The virtual cricket java applet for the Cricket Logo simulator can be viewed online.

Figure 6. The Handy Cricket embedded controller.

In these few paragraphs I've described the personal fabrication concept of building robots using rapid prototyping tools available via the web or off the shelf. In subsequent articles, I'll describe some robot projects that can be explored and investigated via hands-on experimentation. The rapid prototyping tools discussed in this article will be investigated through personal fabrication experiments and projects.