Arduino - poznámky

• A4988

A4988

TMC2100

DRV8825

#define StepsPerDegreeAxis1  2624.0  // calculated as    :  stepper_steps * micro_steps * gear_reduction1 * (gear_reduction2/360)                                 
                                     // My NEMA 17          :  200           * 8           * 1               *  144/360              = 640
                                     // My NEMA 17          :  200           * 8           * 2.05            *  144/360              = 1312
                                     // My NEMA 17          :  200           * 16          * 2.05            *  144/360              = 2624
                                     // My NEMA 17          :  200           * 32          * 2.05            *  144/360              = 5248
                                
                                     
                                     // Axis2 is for Dec/Alt
#define StepsPerDegreeAxis2  1312.0   // calculated as    :  stepper_steps * micro_steps * gear_reduction1 * (gear_reduction2/360)
                                     // My NEMA 17          :  200           * 8           * 2.05            *  72/360              = 656
                                     // My NEMA 17          :  200           * 16          * 2.05            *  72/360              = 1312
                                     // My NEMA 17          :  200           * 32          * 2.05            *  72/360              = 2624

                                     
                                     // the EM10b has two spur gears that drive the RA/Dec worms, they give an additional 1.25:1 reduction
                                     // in addition to the 18:1 gear heads on the steppers for a 22.5:1 final ratio before the worm/wheels at 144:1
                                     
                                     // PEC, number of steps for a complete worm rotation (in RA), (StepsPerDegreeAxis1*360)/gear_reduction2.  Ignored on Alt/Azm mounts.

#define StepsPerWormRotationAxis1 6560
                                     // My   8m step          : (640*360)/144 = 1600   
                                     // My   8m step          : (1312*360)/144 = 3280   
                                     // My  16m step          : (2624*360)/144 = 6560
                                     // My  32m step          : (5248*360)/144 = 13120

Frekvence pro Seben RA  motor  12.67Hz


144:1 (worm gear) and 2.05:1 (printer gears) = 295.2:1. with a 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 y 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), wich 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 frecuency can be used according t desired feed speed. 
a switch for direction changing of the stepper. is also recommended