OnStep for Seben EQ3 mount by RomanHujer

Last crawled date: 3 years ago

Adapting SEBEN EQ3 telescope mount or similar types to OnStep goto controller, by Howard Dutton project.
How to this working? See my video: https://youtu.be/mOXqw7EN8YE
My OnStep Controller Box on base STM32 Blue Pill
Alternative OnStep Cotroller Box on base MiniPCB2 and Teensy3.2

Old OnStep Controller Box for on Arduino Mega2560 board

FreeCAD sources on Github
Version 1.0 - 3D printed gears 54:16
1x RA motor is 17HS15-1684S-PG5 with Gear Rate 3.7:1 (1+46/17) :1
1x DEC motor is 17HS15-1684S-PG5 with Gear Rate 3.7:1 (1+46/17) :1
OnStep config.XXX.h for A4988 stepper drivers with 16 micro steps
RA primary worm screw transver raito is 138:1
DEC primary worm screw transver raito is 88:1

// Axis1 is for RA/Az
// calculated as : stepper_steps * micro_steps * gear_reduction1 * worm_reduction / 360
// : 200 * 16 * 54 / 16 * (1+46/17) * 138 / 360 = 15342.35294
#define StepsPerDegreeAxis1 15342.35294

// Axis2 is for Dec/Alt
// calculated as : stepper_steps * micro_steps * gear_reduction1 * worm_reduction/ 360
// : 200 * 16 * 54 / 16 * (1+46/17) * 88 / 360 = 9783.529412
#define StepsPerDegreeAxis2 9783.529412

// PEC, number of steps for a complete worm rotation (in RA)
// calculated as : (StepsPerDegreeAxis1*360)/worm_reduction.
//: (15342.35294 *360)/138 = 40024
#define StepsPerWormRotationAxis1 40024L


Version 2.0 - metal parts and belt GT2 reduction 60:25
2x GT2 Timing Pulley with 60 Teeth and Bore 5mm for 6mm belt
2x GT2 Timing Pulley with 25 Teeth and Bore 8mm for 6mm belt
2x GT2 Timing Belt 6mm wide 2mm pitch 180mm-2GT 90 teeth
1x RA motor is 17HS15-1684S-PG5 with Gear Rate 3.7:1 (1+46/17) :1
1x DEC motor is 17HS4413AG5.18-X with Gear Rate 5.18:1 (1+46/11):1
OnStep config.XXX.h for TMC2130 stepper drivers with 32 micro steps
RA primary worm screw transver raito is 138:1
DEC primary worm screw transver raito is 88:1

// Axis1 is for RA/Az
// calculated as : stepper_steps * micro_steps * gear_reduction1 * worm_reduction / 360
// : 200 * 32 * 60 / 25 * (1+46/17) * 138 / 360 = 21820.23529
#define StepsPerDegreeAxis1 21820.23529

// Axis2 is for Dec/Alt
// calculated as : stepper_steps * micro_steps * gear_reduction1 * worm_reduction/ 360
// : 200 * 32* 60 / 25 * (1+46/11) * 88 / 360 = 19456.00000
#define StepsPerDegreeAxis2 19456.00000

// PEC, number of steps for a complete worm rotation (in RA)
// calculated as : (StepsPerDegreeAxis1*360)/worm_reduction.
// :(21820.23529 *360)/138 = 56922
#define StepsPerWormRotationAxis1 56922L

Auxiliary PCBs for this version:

RA PBC design is on EasyEDA * DEC PBC design is on EasyEDA

OnStep SHC (Smart Hand Controller)

OnStep ST4 Handheld controller


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