Astro Tracker for EQ1 mount

thingiverse

A tracking device for the old basic EQ1 mount of my 114/900 newtonian telescope. Parts List: Amount Name 1x Bipolar stepper motor 1x Arduino Uno or similar 1x Stepper Driver Pololu A4988 compatible 1x Potentiometer 10k or similar 1x Capacitor 100µF, (at least 16V) 1x 605ZZ ball bearing 1x M5x8 Allen Key screw 1x M5 washer 2x M3 Grub screw 2x M3 Nut 4x M3x10 Allen Key screw 1x 9 - 12 V battery 1x EQ1_MountPlate_q3d_RC1.stl 1x BigGear_41_q3d_RC1.stl 1x SmallGear_20_q3d_RC1.stl Print Settings Rafts: Doesn't Matter Supports: Doesn't Matter Infill: 40% Notes: Gears without Support, the mounting plate could need support depending on your printer. I recommend 30% or more infill. Post-Printing After Printing make sure the cogwheels catch smoothly. Remove the support structure of the plate if you used support for printing. Tap a M5 thread into the back of the bigger cogwheel. Mount the stepper motor onto the flat side of the mounting plate and secure it with 4 M3x10 screws. Push M3 nuts into the top of each of the cogwheels. Align each M3 Nut with the bore and and add the grubscrews loosely. Gently push the small gear onto the stepper motor, sprocket facing the stepper. Push the ball bearing into the opening on the other side of the mounting plate. Align the bigger gear and join the 605 ball bearing with the bigger gear via the M5x8 bolt, be sure to place a washer between the bearing and the gear part. Attach the assembly onto the side of your EQ1 mount as seen in the video. There should be a M4 threaded bore for fastening. The shaft of the worm gear should fit into the other side of the bigger cogwheel of the assembly. If everything sits well fasten the mounting screws and the grub screws. The first version just used some spare RepRap hardware I had consisting of a RAMPs board, an Arduino Mega 2560 and a Pololu a4988. The circuit is fairly simple to build on a breadboard or similar (see schematics). In the video you can see me using a Protoneer cnc shield on a simple Arduino Uno and a 12V fan for cooling. If you're using the cnc shield the stepper driver has to be placed in the X-slot and the 3 jumpers beneath it have to be closed ( -> microstepping x 16 ). The potentiometer can be attached to the "SCL" pin for the signal. ( conveniently 5V and Gnd are just one row down the line) Adjust the Arduino sketch if necessary if you use a different pin assignment. How I Designed This Designed during winter 2014/15 with Openscad, FreeCAD, Fritzing, Arduino IDE