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What Else Can the HBG3 Do?

The HBG3 has a number of other useful capabilities, including GPS ("SkySync"), a Nunchuck (thumbstick) interface, OLED display, Smart 2X DewHeater controller, Focus-Motor emulation and/or control, wireless Nexstar+ hand-controller, workarounds for Celestron bugs, etc. Read on!

  • There is provision for an optional $20 GPS receiver module (eg. Beitian BE-182), which adds fully compatible multi-system GPS functionality at a fraction of the cost of the Celestron "SkySync" unit, with a much more modern chipset and better reception. Use of a GPS eliminates tedious and error-prone data entry for Time, Date, and Location prior to aligning the mount each session when used with a Celestron hand-controller or CPWI software.
  • A feature unique to the HBG3 is "Fake GPS" capability, which can be used either with or without a real GPS recevier attached. Fake GPS instructions are here.
  • A connector on the HBG3 enables plugging in a "Nunchuck" thumbstick controller (see here), which can be used to slew the mount (automatic variable speed) in both axis, as well as to control a HomeBrew or Celestron Focus Motor if present. Nunchuck controllers are commonly available (eg. Amazon) for under $10. The no-name "clones" tend to behave better than the original Nintendo branded ones.
  • The HBG3 with Nunchuck can also be directly connected to a Celestron Focus Motor in standalone mode, when used with a non-Celestron mount. In this scenerio one could power the HBG3 with 5V into its USB port. Or one might instead feed 12V into the HBG3 using its GND and RAW pads, and the HBG3 will then pass that 12V through the AUX cable to also power the Focus Motor, simplifying the overall wiring at the mount.
  • A stepper motor can be wired to the HBG3 through a motor driver module, and then act the same as a Celestron-branded Focus Motor, with full control from the hand-controller, CPWI, and SkyPortal/SkySafari apps. This is described more in this post at CloudyNights.
  • When not in Mount-USB mode, the USB port on the HBG3 is available for updating the internal firmware, and also for monitoring and debugging the behaviour of the mount and accessories with a serial terminal program (115200bps). Commands include 'G' (toggle display of GPS NMEA sentences), 'n' (show detailed Nunchuck information), 'v' (verbose tracing of AUX bus and other activity), and other commands that come and go as needed. Begin with the 'help' command!
  • One can also telnet over WiFi to TCP port 3000 on the HBG3, where the same commands and settings can be viewed and modified to suit individual requirements. This includes permanently changing the WiFi SSID for Direct Connect, and even assigning a security passphrase onto the WiFi. Use the "get all" command to view settings, and use "set" to change them individually. The "save" command makes any changes permanent, and "load defaults" (followed by "save") reverts everything to "factory defaults".
  • A standard Arduino style WizNet Ethernet module (eg. W5100, W5500) can be directly wired to the HBG3, providing the option of a long-distance wired network connection to the mount instead of using wireless. This is fully compatible with anything that can normally connect over WiFi, such as CPWI and SkySafari+/pro.
  • Multiple HBG3 units can be connected simultaneously to the same mount, if desired. While this is not at all necessary, sometimes people find it convenient to build separate devices for various functions, rather than combining them onto a single HBG3. No problem.
  • The HBG3 normally turns off WiFi and/or Bluetooth when not in use (eg. Bluetooth off when using WiFi, etc.). But the MUSB switch also acts as an RF-Kill switch, turning off both Bluetooth and WiFi when in the "on" position.
  • When a HBG3 connection (WiFi, Bluetooth, USB, or ethernet) is in use, the unit also sends a command to temporarily turn off the built-in WiFi of a Celestron Evolution mount, reducing interference/power when it is not needed.
  • CPWI up to at least version 2.5.2 sends invalid commands to the mount when querying the CORDWRAP setting. As of version v7.9 of the HBG3 firmware, the HBG3 will now "correct" those commands to avoid confusing the mount or accidently enabling CORDWRAP.
  • The Open Source firmware of the HBG3 includes other special protocol adjustments, to enable use of the device with older Celestron mounts which otherwise would not work with WiFi or other modern Celestron accessories.
  • A variant of the HBG3 can be wired as a protocol Relay (or "bridge"), with one AUX port connection to the mount, and secondary AUX ports provided by it for accessories (not a simple splitter). This "HBG3-Relay" is used to modernize the old Nexstar GPS mount, enabling it to work with the StarSense AutoAlign accessory, and to work around issues with other troublesome or "unsupported" devices on any mount. Particularly the 6SE/8SE.
  • The HBG3 provides two channels of Smart Dew Heater Control functionality, using an optional SHT30 ambient sensor for temperature and humidity, and thermistor inputs from (eg.) the Celestron Dew Ring accessories (see here). The current dew point and thermistors are continuously monitored, and the dew heater outputs are adjusted to maintain just the right amount of heat to prevent fogging up. A small bit of extra hardware and separate 12V supply is necessary for actually driving the high current 12V output to the Dew Heaters. The Dew Heater functionality provides a faithful emulation of the Celestron 2X DewHeater Controller, enabling monitoring and control from Celestron Hand-Controllers and also from CPWI software on a computer.
  • There are dedicated mounting holes for direct attachment of a small I2C OLED display, and most HBG3 devices include it. This shows various screens of status information, an an associated momentary contact button switch enables toggling through the sequence of screens, changing some settings, updating firmware, and even turning off the display. This same button is also used to adjust the Dew Heater control settings. A 0.96" white OLED is recommended, with red filter material fastened over the display.
  • There is an optional "WiFi Relay" mode of operation, which requires that the Tx/Rx signals be jumpered together. This mode enables one HBG3 in client mode to connect to another HBG3 (or 3rd generation Celestron WiFi) in server mode, and bridges all AUX bus communications between the two. One way this can be used is in combination with a battery to create a wireless connection for the Nexstar+ or StarSense hand-controller.
  • Ever want to attach the Optical Tube Assembly (OTA) backwards on an ALT/AZM mount? So that the fork arm can be more conveniently located to the operators right-hand side? Normally this would result in the ALT motor movements being the exact opposite of what one needs, and things would end rather Badly. As of v7.0 of the HBG3 firmware, one can now set a variable to enable use of "mount.reversed.alt" mode for anything that is controlling the mount via a connection that passes through the HBG3: WiFi, Bluetooth, or USB. For this mode to also work with a Celestron hand-controller, a HBG3-Relay device is needed, with the hand-controller connected on the Relay side of things.

    On Serial or Telnet port 3000, use these commands to enable this mode:

    set mount.reversed.alt 1

  • Use of Celestron Firmware Manager (CFM) is not tested and not supported via the HBG3 (too risky!). The unit actively tries to prevent such use. MCUpdate and HCUpdate are also NOT supported.
  • There are two LEDs on the HBG3. The red one lights up when the unit has power. The blue LED flashes once briefly at power-on, and then later blinks three times in succession to indicate a working connection to a Celestron mount. It also turns on longer when confirming saving of a Focus preset in standalone mode.
  • There is preliminary support for use of the HBG3 functions in conjunction with the Celestron StarSense for SkyWatcher product. It provides GPS and Nunchuck functionality, and also WiFi/Bluetooth support for SkySafari+/Pro -- work ongoing.
  • The standard firmware includes a full StarSense AutoAlign (SSAA) Camera Simulator, useful for testing firmware updates and other software without having an actual SSAA Camera attached to the mount. The SSAA system is more demanding of communications connections than regular operation, so being able to simulate one here enables easier testing of setups and software under the most stressful of conditions.
  • A similar feature implements a partial (but working) StarSense AutoGuider (SSAG) Simulator.
  • The USB-Serial interface of the HBG3 includes extensive bus monitoring capabilities, and can be used to trace protocol communications between all devices on the AUX bus.
  • The firmware of the HBG3 is Open Source, and actively worked on and supported. There are frequent updates to improve and extend functionality.
  • That's most of it, but not all. This page will be updated with additional information and detail in the future.

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