PicGoto Step-dir Telescope Controller (V4 2018) for bipolar steppers


DIY Goto telescope controller based on Angel Caparros's PicGoto system.

  • PicGoto firmware for bipolar stepper motors (Step-dir version)
  • USB-TTL (PL2303 modified adapter, see HERE!), Bluetooth (HC-06), WiFi (ESP-01 here) and Hand Remote Controller (with D1-mini, here
  • SkySafari interface in WiFi mode
  • DRV8825/A4988/LV8729 stepper drivers support
  • Overcurrent protection with fuse
  • Switches for TTL/BT/WiFi use with control LEDs
  • Auxiliary and Focus steppers support
  • Internal ventilation fan
  • 9-24V power input

Hardware list

Main components list (schematic available in Image Gallery)

  • R1,R2 (value depends on stepper motor characteristics) 
  • R3 1K (pull-up for HC-06) 
  • R8, R16, R17 LED’s resistors (value depend on LED characteristics, 470Ω-2K) 
  • R10 10K (pull-up for ESP-01) 
  • R11 10K (pull-up for ESP-01) 
  • R12 1K (voltage divider for HC-06) 
  • R13 2K (voltage divider for HC-06) 
  • C5,C6 22pF, ceramic 
  • C7,C8 100µF, 25V, electrolytic 
  • D1 1N4007 
  • D2 Schottky 1A 
  • D3,D4 BAT42 
  • RA, DEC PIC16F628A 
  • IC3 ULN2803 
  • Q1,Q2 20MHz 
Driver boards
  • DRV8825/A4988/LV8729 (2)


The power input is DC 9-24V and regulated internally by two DC-DC step-down buck modules, one converting Vin to 5V for MCUs, HC-06, Fan and LEDs and the other converting 5V to 3.3V for ESP-01.


On one side of the box you can find two switches beside the control LEDs, the Main Power switch and a switch that activate/deactivate the fan.
Below the LEDs, the two 3-positions small switches that set I/O data mode. Set the switches on the left position if you want Bluetooth mode or set them to the right if you decide for WiFi mode. The switch on the left side controls the data signals while the switch on the right side turns on/off the corresponding module board.


I designed the PCB with Fritzing and the exported Gerber files are available for download here below at the bottom of this page.

Please, be careful connecting the Step-down modules as shown below.

Explore my image gallery for more images of the controller and accessories.

PGT-stepdir 2018

Before using the USB-TTL RJ9 connector jack read carefully this page!

Instructions for configuring and using the Controller will follow soon ...

December 2018

Gigi Giorgi,
Feb 28, 2019, 2:08 AM
Gigi Giorgi,
Dec 21, 2018, 5:26 AM