EQ1 Astro Tracker

thingiverse

A Custom Remix for the EQ1 Astro Tracker System. I Got an Old Stepper Motor with a Short Shaft, So I Had to Mount the Pinion Backwards. This Led Me to Modify the Mounting Plate Design so I Could Attach the Motor in the Opposite Position, Underneath the EQ1 Polar Axis. I Also Included Oval Notches for Adjusting the Backlash of the Gears (My Printer Still Has Calibration Issues, and This Helps Improve Gear Mesh). Both Gear and Pinion Are Designed by 3ddruckqueck. The Gears Require Breaking in. After Some Minutes, Readjust Gear Mesh and They'll Run Quietly. Some Grease Also Helps. I Also Included a Simple DSLR Mount and a Homemade Knob for a 1/4" - 20 Standard Bolt. Hardware Required: NEMA 17 Stepper Motor 10 x M3x12mm Screws 4 x M3 Washer 6 x M3 Nuts. 2 x M6x50mm Countersunk Screws 2 x M6 Locknut 1x 1/4"-20 1" HEX Screw 1 x 626-RSH, Single Row, Deep Groove Ball Bearing (19mm OD, 6mm ID, 6mm Width) Print Settings Printer: Rostock Mini Rafts: Doesn't Matter Supports: Yes Resolution: 0.3mm Infill: 40% Notes: Supports Are Not Required for the Parts Except for the Motor Holder. Some Drilling and Cleaning of the Holes Are Required. Post-Printing Instructions: Use Drills and Countersink Bits to Clean All Holes and Notches. Insert the M3 Nuts into the Gears, and Thread the M3 Bolts. Insert the Ball Bearing into the Gears Holding Plate. Insert the Holding Plate Both Polar Axis Shaft and Elevation Shaft. Put the Stepper Motor in Place with M3 Bolts. Use M3 Washers to Avoid Print Crushing. Keep Them Loose for the Moment. Insert Both Small and Big Gears into the Polar and Motor Shafts (Small Gear into the Stepper, Big Gear into the Polar Shaft as Shown in Photos). Tighten the Gears Bolts. Do Not Overtight. Use a Plastic Bag as a Gauge Between Both Gears. Hold Both Gears Together and Start Tightening the Motor Bolts in a Star Pattern. With a Stepper Driver of Your Preference, and an Arduino, Connect Your Stepper and Let It Run for 20 Minutes at a Moderate Speed to Break In the Gears. Finally Use a Brush to Clean Both Gears. Add a Little Grease to Lubricate the Transmission. It Will Run Quietly. According to My Calculations, the Final Transmission Including the Equatorial Mount Worm Gear: 144:1 (Worm Gear) and 2.05:1 (Printer Gears) = 295.2:1. With an A4988 in a 16 Microstep Mode, a 200 Steps Motor Will Run at 3200 Steps/Revolution. If Polar Axis Should Run Roughly at 23 Hours 56 Minutes and 4,0916 Seconds (Sidereal Day) Per Revolution, This Gives a 82800 S + 3360 S + 4.0916 S = 86164.0916 Seconds/Rev of the Polar Axis. For Each Revolution, the Steps Count for the Motor Will Be (3200 x 295.2= 944640 Steps), Which Gives a (86164.0916 S / 944640 Steps) = 0.091213681 Seconds/Step, or 10.9632676703 Hz. This ~11Hz Signal Can Be Generated Using an Arduino. To Keep Costs Low, a NE555 Can Be Used. For a Fast Feed of the Equatorial Mount, a Higher Trigger Frequency Can Be Used According to Desired Feed Speed. A Switch for Direction Changing of the Stepper Is Also Recommended.