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236 The Ultimate Palm Robot

Adding Sensors to the Pontech SV203

The SV203 has five input ports used for reading data. In this book, we’ve usu-
ally referred to them as analog ports. In fact, they are analog/digital ports—
that is, they read an analog value from the input device, and that reading is
converted to a 1-byte digital value that is sent to the host computer. Since the
value is limited to 1 byte, the value sent by the A/D port is between 0 and 255.
The A/D ports are located on the SV203 in the block of pins labeled J3. The
pins are numbered from 1 to 5, starting in the upper-left corner, and moving
left to right, top to bottom.

The output line from a sensor device is attached to one of the five A/D
ports. Assuming the sensor needs power, the power and ground lines can be
attached in a couple of different ways.

With the PPRK we built in this book, the power and ground lines for the
rangers were attached to the pins in the output block of ports. Those were the
pins labeled S6, S7, and S8 in the block of pins labeled J4 on the SV203. This
gave each sensor its own power and ground line.

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