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HomeBrew Telescope Accessories for Celestron Mounts!

These are a few of the popular HomeBrew telescope projects I have created since 2020. Isn't lockdown fun? Complete wiring diagrams and Arduino source code are provided for each, so that anyone can have a go at making them.


Update Alert: I am in the process of redesigning most of the HomeBrew projects here for vastly improved compatibility across Celestron's product line. The versions until now have relied upon pull-up resistors for driving the bus, and those have proven frustrating and unpredictable from mount to mount.

So a pair of new hardware designs has been developed, one for 3.3V (ESP32, BW16) designs, and another for 5V (Pro-Micro) designs. These new designs use full and proper 5V TTL signaling with tri-stating when idle, the same as most of Celestron's own gear seems to do. Stay tuned for updated versions of the projects below. Anything prior to 17-November-2022 is one of the old designs that use pull-ups. Anything newer will have the much improved electronics instead, and will be clearly labelled as such!


HomeBrew GPS (SkySync clone)

Here are the latest instructions for the SparkFun Pro Micro version of this easy project.
The older Pro Mini based version is archived here.
Also see the CloudyNights Discussion Thread.


HomeBrew Gen3/Gen3a WiFi+Bluetooth Adapter (SkyPortal/SkyQLink clone)

This project has now been redesigned and uses a custom-made printed circuit board (PCB) for the wiring. PCBs can be obtained by emailing me. See this discussion thread on CloudyNights for more details on the new design.

To load the firmware, one can install the Arduino IDE and then the ESP32 support from within there. Then download the HomeBrew esp32_wifi.ino source file, build and download it. Or.. try a pre-built binary image, following these instructions.

Here are the older, no longer recommended instructions for how to assemble this popular project.
The original, more difficult to build version of this project is archived here.
Also see the CloudyNights Discussion Thread.


HomeBrew Ethernet Adapter

The latest and safest design uses the HomeBrew Gen3a PCB for the AUX bus. Here are some construction photos and notes.

There are also notes for an older version of the HomeBrew Ethernet Dongle for Celestron Telescopes.
Also see the CloudyNights Discussion Thread.


HomeBrew Nunchuck Slew/Focus Controller

Here is a solderless breadboard version of the popular HomeBrew Slew/Focus controller, using a Nintendo Nunchuck game controller.
Also see the CloudyNights Discussion Thread.


My Other HomeBrew Projects

More detailed info on these will be added in the future. Here are the CloudyNights discussion threads for them:

HomeBrew AUX Bus Relay/Extension.
HomeBrew Celestron Compatible Smart Dew Heater Controller.
HomeBrew Mount-USB Connection.
HomeBrew Joystick Slew Controller.
HomeBrew All-In-One (AIO) WiFi+BT+GPS+USB+Ethernet+Joystick.
HomeBrew 5GHz/2.4GHz Dual-Band Wifi+BLE Adapter.
HomeBrew Bluetooth Accessory for Nexstar+ USB Hand-Controllers.
HomeBrew Controller prototype for Celestron Focus Motor.
Standalone Controller for Celestron Focus Motor.
How to use the HomeBrew AUX port Bluetooth Feature.
DeWalt 20V Max power supply for 12V Telescope Mounts.
Large Accessory Tray for the Evolution mount.
I also have a StarSense Camera Simulator, but have not released it widely yet. Someday it may grow into a fully functional HomeBrew StarSense Camera.


Telescope Electronics Repairs

I have had success diagnosing and repairing the electronics inside Celestron mounts and hand-controllers:

Fixing Hand-Controller "No Response" Errors.
Evolution Main Board Repairs.
More Evolution Main Board Repairs.


Source code for the All-In-One project

Universal zip archive:
Right-click and "Save-As": allinone.zip (latest version)


Complete pre-configured/patched All-In-One project build environment for Linux

Linux tar archive 331MB:
Right-click and "Save-As": allinone_arduino.tar.bz2


USB Host Shield Library (pre-patched)

Here is the USB Host Shield library with patches already applied to it for the All-In-One project,
and also so that the USB port works for a Nexstar+ hand-controller.
Right-click and "Save-As": USB_Host_Shield_Library_2.0.zip