Star Tracking System Issue – Servo Not Moving Despite Stellarium Data Connection

[Essa Zulfikar Salas]

Hi everyone,

I’ve built a star tracking system using:

• 2x MG996R servo motors

• Arduino Mega 2560

• GY-91 (MPU-9250) IMU sensor

• ESP8266 (for WiFi communication)

The system was tested successfully by the technician who assembled it, but when I tried it at home, the servos didn’t move, even though:

• Stellarium’s remote control plugin is running (http://localhost:8090).

• The website version (localhost:8090/api/objects/info?format=json) receives data when I change planet positions in Stellarium.

• Wireshark shows no connection to port 8090 from the ESP8266.

Setup:

• All devices (PC, ESP8266) are connected via Android hotspot.

• The technician programmed the ESP8266 to work with this setup.

Problem:

• Data reaches the web interface, but the servos don’t respond.

• No communication detected between ESP8266 and Stellarium via port 8090.

Has anyone faced a similar issue? Could it be a network configuration problem (e.g., localhost not accessible from ESP8266)? Any debugging tips?

[Hans]

Hi Essa,

I don't think this is a stellarium problem.
Having said that you can try the following:

Test the network connection to the ESP8266 over WIFI with plain
telnet to the apparent listening port 8090 on the ESP8266. (are
you sure this is the right port for the ESP8266 as well ?).

If that does not work, then don't bother trying to make it work with
stellarium.
Fix the connectivity first.

Good luck.

-- Hans

Essa Zulfikar Salas wrote on 20250601:
> Hi everyone,
>
> I’ve built a star tracking system using:

> -
> 2x MG996R servo motors
> -
> Arduino Mega 2560
> -
> GY-91 (MPU-9250) IMU sensor
> -

> ESP8266 (for WiFi communication)
>
> The system was tested successfully by the technician who assembled it, but
> when I tried it at home, the servos didn’t move, even though:

> -

> Stellarium’s remote control plugin is running (http://localhost:8090).

> -

> The website version (localhost:8090/api/objects/info?format=json)
> receives data when I change planet positions in Stellarium.

> -

> Wireshark shows no connection to port 8090 from the ESP8266.
>
> Setup:

> -

> All devices (PC, ESP8266) are connected via Android hotspot.

> -

> The technician programmed the ESP8266 to work with this setup.
>
> Problem:

> -

> Data reaches the web interface, but the servos don’t respond.

> -