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Solderless Assembly of a Nunchuck Slew/Focus Controller

Here is one way to assemble a slew/focus controller for a Celestron mount, without any real soldering involved. Click the first image below to get started.

And/or peruse the CloudyNights discussion thread for this project.

Here is the wiring diagram for this project, with two diodes and a 100K resistor.
wiring 		Here all all of the parts required for this build. A mini solderless breadboard, a 100K resistor, two diodes (1N5817, or 1N4007, or 1N4148), five jumper wires, a genuine SparkFun Pro Micro 5V/16MHz board (part #DEV-12640), an Adafruit Wii Nunchuck Breakout Adapter (part #4836), and a keystone RJ12/RJ25 6P6C connector with five solid-core wires attached. I got the wires from a scrap of ethernet cable.
img20221118115438 		Begin by wiring the red and black wires as shown, plus the 100K resistor, and the two diodes. Pay careful attention to the striped ends of the diodes. The Nunchuck adapter plugs into the final five rows on the top corner of the breadboad, as shown.
img20221118115902 		Now the genuine SparkFun Pro Micro 5V/16MHz board plugs in over top of the resistor and wires. This MUST be a real SparkFun board, as only those can handle 12V from a telescope AUX port without going up in smoke. I cheated here and used a clone, but only after making it safe by replacing the poor on-board power supply chip with the same "KB50" chip that SparkFun boards use. Tricky!
img20221118115950 		Next, add the red wire from VCC to VIN of the Nunchuck board.
img20221118120101 		Here is the 6P6C connector, clearly showing the order of connections. They are numbered left to right, and we have (1) Not-Connected, (2) RX, (3) +12V, (4) TX, (5) Ground, (6) Busy. The colours don't matter, so long as one keeps track of which wire is which when connecting them in the next step.
6p6c
Now wire the 6P6C connector to the bread board. RX(brown) goes to the RXI pin, Ground(white) goes to any GND pin, Busy(blue) goes to Pin-4, TX(green) goes to one end of one diode as shown, and +12V(orange) goes to one end of the other diode, as shown.Triple check this, put it aside, and check it AGAIN tomorrow, before plugging it into a telescope mount. Get it wrong, and it can destroy things. Get it right, and there will be no issues.
img20221118120415 		Now complete the wiring, by connecting the Nunchuck SCL to Pin-3, and the Nunchuck SDA to Pin-2.
img20221118120757 		Plug it into a PC, and both the Pro Micro and the Nunchuck boards should light up as shown. If not, quickly unplug it, and look for wiring errors.If all is good so far, fire up the Arduino IDE, select the correct "Port", open the Serial Monitor window for 115200bps, select AVR->Leonardo as the Board Type, and flash this "sketch" to the Pro Micro: joystick.ino.txt. Without connecting anything to a telescope yet, move the thumbstick around and see if there is output on the Serial Monitor. If not, ask for help at CloudyNights! Otherwise, if you are 100 percent sure about the wiring, connect it to a telescope mount and try it out. If not 100 percent sure, ask for help at CloudyNights!!After testing, with everything working, you could consider blobing hot-melt glue over it all to secure everything permanently in place. Or actually solder up a permanent circuit.
img20221118121013 		Here's a soldered-up version I made earlier, wrapped with heat-shrink tubing.
img20220926224405
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