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Building an AUX-port Ethernet Dongle for use with Celestron telescopes

Now to wire up the AUX port interface. Begin with the diode, stripe DOWN, into the TXO hole on the Arduino board. Then a 51K-ohm (give or take) resistor into the Vcc hole on the opposite edge of the Arduino board. Twist the resistor around the stiffer diode lead, and solder all three connections.
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Another view, before soldering.
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Side view of the diode, showing the stripe DOWN.
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All soldered and snipped. Looking good!
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Now..thread a cable tie carefully under the wiring and around the back side of the Arduino board. Insert the 6P6C cable through it, and tighten the cable tie to secure it in place during the wiring procedure. Note that this will eventually be wrapped in heat-shrink tubing which will hold it even better.
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Begin routing and soldering the five wires in place. Best to start with the RXI line, then the GND wire, followed by the wire to Pin-4 (the BUSY line). These all attach directly into the holes on the Arduino board, as shown.
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Now route the +12V wire to the Buck converter and solder it there. And finally the TX wire gets soldered at the top of the 51K-ohm resistor that was attached earlier.
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That's it for the wiring, other than fixing any mistakes!
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Now, before applying the heat-shrink tubing, a little extra protection is needed in two places. Use tweezers to pull a small square of (ORANGE here) electrical tape underneath the solder connects at the buck converter. And similarly a second square between the buck and the exposed diode wire, to prevent short circuits in either location as things get squeezed together. The solder joints under the buck converter should be smooth with no point protrusions.
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My tubing of choice: adhesive backed (on the inside) 32mm clear heat shrinkable tubing.
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Apply a hot air gun to it, warming it evenly all around until it shrinks tight. Then, while it is still hot, squeeze the tubing flat around the cable, and also all around the RJ45 jack. The internal adhesive should stick in place as it cools. The "mode switch" may require cutting-out afterward. Oh, and be careful when heating around the switch -- it can melt!!
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Front view of the finished product, after a little bit of trimming with a sharp knife.
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There we have it.. five new ethernet dongles!
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