Hardware Hacking Projects for Geeks

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Part II: Advanced Hacks, Tools, and Techniques

WARNING

When working with high voltages, I observe what I call the One-Hand Rule. This

means you should keep one hand in your pocket whenever you are handling live,

high-voltage circuits. Do not be tempted to use both hands at once; if one hand

happens to brush against a high-voltage point and the other is touching a ground

point, your body will create a path for electricity to flow across your heart. This

high voltage may cause your heart to stop, which is a very bad thing!

Software Setup Instructions

I decided to keep the software running on the TCU simple. It performs the

basic functions listed here:

• Controls LCD

• Reads button events from the front panel

• Reads and interprets data from the RS-232 serial port

• Controls heating coil selector relay

The TCU may be operated with or without a host PC gateway. When oper-

ated alone, it allows toast pattern selection from the buttons on the front of

the TCU. When operated with a host gateway PC, toast pattern selection

could be based on data gathered from the Internet by sending a command

to the TCU over the gateway serial port.

The software written for the BasicX controller is listed in Exhibit B. The

protocol the TCU uses is simple: when it receives the character A, it selects

the top heating elements; when it receives the character B, it selects the bot-

tom heating elem ...