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UNIX BASED SYSTEM, SUCH AS A RASPBERRY PI MICROCOMPUTER.  MY HOME
AUTOMATION SYSTEM RUNS ON A RASPBERRY PI, BUT I THOUGHT IT WOULD BE MORE
CONVENIENT TO RUN A SECOND INSTANCE OF OPENHAB ON MY RADIO STATIONS PC,
AFFORDING DIRECT CONTROL OF THE ARDUINO THROUGH ITS USB PORT.  THE
FEASIBILITY OF THIS IDEA WAS REINFORCED BY THE EXISTENCE OF A SERIAL
BINDING FOR OPEN HAB, WHICH ALLOWS COMMUNICATION TO ANY DEVICE CONNECTED
VIA AN RS232 PORT OR EMULATOR.  THE ACT OF CUSTOMIZING THE INTERFACE COULD
THEN BE DONE SIMPLY THROUGH SOFTWARE BY MODIFYING THE ITEM, RULE, AND
SITEMAP FILES THAT CONFIGURE THE OPENHAB GUI.  HARDWARE THE HARDWARE FOR
THE ACTUAL SWITCH IS QUITE SIMPLE.  I USED AN ARDUINO MEGA 2560
MICROCOMPUTER FOR THE INTERFACE SEE FIGURE 1A.  IT HAS THE REQUIRED NUMBER
OF DIGITAL I/O INTERFACES AND IS AVAILABLE FOR LESS THAN 20 AT SEVERAL
VENDORS.  FOR THE RELAY BOARDS, I USED TWO SAINSMART 16 CHANNEL RELAY
MODULES.  THESE UNITS ARE COMPRISED OF 16 SINGLE POLE DOUBLE THROW SPDT
RELAYS, PLUS ALL OF THE SWITCHING CIRCUITRY TO CONVERT A 5 V DIGITAL HIGH
OR LOW SIGNAL TO THE APPROPRIATE SWITCHING STATE OF THE RELAYS.  FOR ANY
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