A DIY serial-to-WiFi adapter for Sky-Watcher telescope mounts for controlling the mount using the SynScan app for smartphone or tablet. It has been designed for and tested with the EQ6R-Pro mount.
This software and electronic circuit are provided “as is”, without any warranty. Use them at your own risk. Incorrect wiring of the circuit or component failures may result in damage of your mount's motor controller board or your microcontroller. The author is not responsible for any damage, data loss, injury, or other consequences resulting from their use.
This repository provides the description of the electronic circuit, the Arduino sketch as well as design files for a 3D-printable housing to build a cheap serial-to-Wifi adapter compatible with Sky-Watcher telescope mounts. It has been tested with an EQ6R-Pro mount.
The sketch uses a NodeMCU ESP8266 development board to connect to a WiFi network. A tablet or smartphone in the same network with the SynScan app installed can then be connected to the mount to control it as a replacement of the hand controller.
The following hardware components are needed to build the adapter:
- RJ45 connector break-out board
- NodeMCU ESP8266 development board
- Voltage converter
- OLED display
- 3 resistors (100 Ohm)
The electronic circuit is shown below
The sketch SkyWatcherWifi.ino can be compiled and uploaded to the NodeMCU
using the Arduino IDE.
Prior to compilation, rename or copy the file WifiCredentials.example.h to
WifiCredentials.h and enter your Wifi SSID and password.
By default, the adapter will use the fixed IP address 192.168.178.101 and
the gateway address 192.168.178.1. This can be changed in the sketch to
match your preferences:
IPAddress local_IP(192,168,178,101);
IPAddress gateway(192,168,178,1);
IPAddress subnet(255, 255, 255, 0);
Make sure to choose an IP address which is not assigned to any other device in your network.
Important: Never connect the adapter simultaneously with the RJ45 port to the mount and the USB connection to the computer! The NodeMCU would be powered both from the mount and your computer, which will most likely damage one of the components!
Make sure to adapt the Wifi credentials and IP address according to your needs prior to compilation and upload the sketch to the NodeMCU (see previous section).
Then, disconnect the adapter from the USB port and connect it via RJ45 to the mount. After powering the mount, the NodeMCU should connect to your Wifi.
Install the SynScan Pro app on your smart phone or tablet. I recommend using the Pro version as it offers more features. I have tested this with the SynScan Pro app version 2.6.10.
Make sure the app will find the mount by setting the correct IP. On the main menue,
go to Settings and then Connect Settings as shown below. Go to the tab
Network. Here, you can either have the app search for the mount by probing
all devices in the network (not used here) or enter the fixed IP address of the
NodeMCU directly.
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Now, go back to the main menu and connect to the mount by clicking on the gray
bar Connect on the top of the screen. The bar will change its text to
Equatorial Mode in case of the EQ6R-Pro mount. Your are now ready to go!
To disconnect from the mount, click the gray bar on the top of the screen again
and select Disconnect.
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The Stellarium Mobile app offers telescope control as part of its charges Plus version. Stellarium requires the SynScan App as a bridge to send the commands to the mount (see here for more information). The most convenient option is to run both apps on the same device.
It is recommended to put the electronics into a proper housing to avoid
shortening of contacts. Design files made with FreeCAD
for a 3d-printable enclosure can be found in the folder housing. These files
can be exported to stl format and then converted into gcode in the slicer
of your choice. The print is shown below.
Thanks to Vladimir Atehortua for providing the original sketch, which served as inspiration for this project. His version can be found here.
A modification by Volker van Aken to use the NodeMCU in station mode instead of access point mode can be found here.