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ESP32Focuser Hardware

This is a repository for storing documentation for my ESP32Focuser project.

Описание на русском

Deutsche Beschreibung

What is that about

Focuser for astronomy telescope based on ESP32 controller. Comportable with Indilib (http:/indilib.org/) and ASCOM (https://ascom-standards.org/). The controller uses the protocol Moonlite (as documented in the indilib project).

What hardware do I need

The firmware runs on a ESP32-DevKitC board. It uses also the BIGTREETECH TMC2209 V1.2 Stepper Motor Driver to drive the motor on a super-silent and vibrationless way. Basically, you only need this two boards to start using the focuser. If you want to build it on a more resilient way, you can follow intructions below.

Schematics

Schematics diagram can be found as a KiCad project folder. You can donwload shematics as pdf here.

The schematics is pretty easy. You just connect the pins of the ESP32 dev board with the TMC2209 board, add power supply and connect motor - from this point you can control the focuser from the computer over ASCOM/INDI driver. If you want to use an optical encoder as a handcontroller (what I would really advise you if you want to get rid of vibrations when you touch the telescope focuser knob), connect it to the pins on the ESP32 board as well.

Wiring table

Please use the wiring table as reference, it might get outdated. For the most latest schematics version, check the KiCad project.

Description ESP32 board TMC2209 board Note
DIR 32 DIR
STEP 33 STEP
CLK 25 CLK
PDN 26 PDN + PDN not used
MS2 14 MS2
MS1 12 MS1
EN 13 EN
ENC1 2 Encoder output 1
ENC2 15 Encoder output 2
5V 5V VDD
12V VM Motor power supply

Stepper motor

I use the 17HS2408 stepper motor, as it fits well for 12v supply: it has 8 Ohm phase resistance what leads to 1.5 Amps phase current, it's a bit over the specification (rated current 0.6 Amps) but as it's not supposed to continuously work on high speed in this project,it works just fine, has enough torque and does smooth movements.

BOM

Aka bill of material

Description AliExpress link Notes
ESP32-DevKitC https://www.aliexpress.com/item/4000103411061.html
17HS2408 stepper motor https://www.aliexpress.com/item/33033986185.html
7 M3 screws for motor and encoder https://www.aliexpress.com/item/32965979997.html M3 50pcs + 5mm
TMC2209 board https://www.aliexpress.com/item/33029587820.html
Optical rotary encoder CALT ES38 https://www.aliexpress.com/item/33028641351.html 5v 600ppr
13x32mm Encoder knob https://www.aliexpress.com/item/33039964137.html
Motor shaft coupler 5mm x ?? mm https://www.aliexpress.com/item/32913158582.html
OR alternatively to the direct coupling your motor with the focuser, you could use a belt like this below
GT2 Pulley 20 tooth ø 5mm https://www.aliexpress.com/item/32724156349.html
GT2 Closed Loop Timing Belt https://www.aliexpress.com/item/32950422029.html
12v female plug 5.5mm x 2.1mm
12v→5v DC-DC step down converter board https://www.aliexpress.com/item/32742116421.html
Hand controller connector M GX12 5 pin for encoder https://www.aliexpress.com/item/32869491577.html
Hand controller connector M GX12 4 pin for motor https://www.aliexpress.com/item/32869491577.html
115 90 55mm plastic enclosure case https://www.aliexpress.com/item/32709832386.html
100x68x50mm plastic enclosure case for encoder https://www.aliexpress.com/item/32792270384.html
Push button for handcontroller https://www.aliexpress.com/item/32965284265.html
Micro USB cable tbd
2.54mm Wire Cable Connector 4 pin https://www.aliexpress.com/item/32954418743.html
Prototyping board 5x7 cm https://www.aliexpress.com/item/32853911495.html
Cable for motor 4 cores 0.3mm 22awg https://www.aliexpress.com/item/4000714461664.html

Pictures

board1.jpg board2.jpg handcontroller.jpg assembled.jpg assembled2.jpg assembled3.jpg assembled4.jpg