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April 29th
Circuit Board

This section gives some basic electronics and robotics information along with helpful links. I also detail a lot of my projects. For most of them I've included schematics. I use ExpressSCH for drawing them and ExpressPCB for designing circuit boards. They are a free package from You can download for free and get your boards professionally manufactured for very reasonable prices. Of course, with the final layout you can also etch your own boards at home if you choose.

March 11, 2009


This project was from David Cook's "Robot Building for Beginners". You should check out his site at He has a ton of great information and has written two books that take you from a complete novice through building advanced robots with microcontrollers and even aspects of machining parts. After some playing around with BEAM robotics, this was my first real robotics project. It's a line following robot that uses CdS photocells and an LM393 comparator chip to sense brightness changes on a surface. The robot can be switched to follow a light line on a dark surface or vice versa. It was a fun project and Dave's book details everything from start to finish from prototyping on a breadboard to troubleshooting the final product. Here are some pictures of mine:

This is the schematic for the project. It uses separate LM393 chips for each motor and a DPDT switch to allow for following a light or dark line.

Circuit Board
The top of the board shows the LED's, switches and battery connector.

Close Up
Here you can better see all the idividual components. It takes surprisingly few parts to make this work.

Underneath you can see the rat's nest of point to point wiring. I'd like to build another one and use an etched circuit board.

Front View
This picture shows how the circuit board fits into the sandwich container.

Back View
From the back you can see the power switch, battery holder, and switch for light or dark line following.

Here's a video that shows the robot in action.

Other Projects
My second microcontroller project - June 18, 2011
An audio controlled servo - June 1, 2011
My first microcontroller project - May 17, 2011
I built a motion controlled cat fountain - March 24, 2011
A 555 timer project - December 17, 2009