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--- 2008:rondine_june_2008 [2008/06/13 22:11] – tomgee
+++ 2008:rondine_june_2008 [2008/06/29 19:59] (current) – tomgee
@@ Line 5: / Line 5: @@
 The device chosen to do this is AVR based because I had the hardware and tools. The sensor is the ubiquitious One Wire DS1820 from Maxim which I have lots of experience with. A major plus to the DS1820 is the fact the probes are pre-calibrated at the factory. I will be enclosing the chip inside a copper probe using a technique developed for the Kahlo project.\\
-Unique for me is the addition of more than a single probe to a wire. The former QYX terminal I hacked for this purpose only had one convenient port pin. I rewired an old network/ethernet switch to serve as a passive one wire hub. All the probes plug into the hub and one probe comes out of it to the AVR subassembly. This AVR assembly has a Digi Xbee module for wireless connectivity.\\
+Unique for me is the addition of more than a single probe to a wire. The former QYX terminal I hacked for this purpose only had one convenient port pin.
+I tried to rewire an old network/ethernet switch to serve as a passive one wire hub. This didn't work because two of the pins are connected together internally. When I took the multiple RJ45 connector off with a blow torch I saw the traces for the internal connections.
+I ended up gluing brand new individual RJ45 conns to a baseboard and hand wiring the pins as my hub prototype.
+I will have  to make a circuit board and have all the probes plug into the hub with one probe coming from it to the AVR subassembly. This AVR assembly has a Digi Xbee module for wireless connectivity.\\