In order to support controlling various Arduino-compatible devices using the simplest manner possible, Scott Lawrence has concocted a simple system that daisy-chains the serial port of each Arduino do the next. Then a master Arduino can send data down the line to each subsequent Arduino, and they can take action if they recognise the command, or pass the data on to the next. My memory is a little vague but this reminds me of the Microbee Beenet system. Nevertheless Scott's system is simple and works - and sometimes that's what we want.
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