Tutorial Six: Simple Client

This tutorial demonstrates how to create a simple INDI client that can control a CCD simulator. It shows how to connect to an INDI server, access device properties, and perform operations like setting the camera temperature and taking exposures.

What You’ll Learn

  • How to create an INDI client by inheriting from INDI::BaseClient
  • How to connect to an INDI server
  • How to access and modify device properties
  • How to handle property updates and BLOB data

Source Code

The source code for this tutorial can be found in the INDI library repository under the examples/tutorial_six directory.

INDI Client Development

INDI clients connect to INDI servers to control devices. The key steps for implementing an INDI client are:

  1. Create a class that inherits from INDI::BaseClient
  2. Connect to an INDI server
  3. Watch for devices and properties of interest
  4. Handle property updates and perform operations

Code Explanation

This tutorial demonstrates:

  1. Client Setup:

    • Creating a client class that inherits from INDI::BaseClient
    • Connecting to an INDI server
    • Watching for the “Simple CCD” device

  2. Device Control:

    • Setting the camera temperature
    • Taking exposures
    • Receiving and saving FITS images

  3. Property Handling:

    • Watching for specific properties (CONNECTION, CCD_TEMPERATURE, CCD1)
    • Handling property updates
    • Processing BLOB data

Running the Tutorial

To run this tutorial:

  1. First, run the CCD simulator (tutorial_three):

    cd /path/to/indi/build
indiserver -v ./tutorial_three

  2. In another terminal, run the client:

    cd /path/to/indi/build
./tutorial_client

  3. You should see the client connect to the server, set the temperature to -20°C, and take an exposure when the temperature is reached.

  4. The client will save the received image as “ccd_simulator.fits” in the current directory.

Next Steps

This tutorial demonstrates how to create a simple INDI client. In Tutorial Seven, we’ll learn how to create a telescope simulator that uses the INDI Alignment Subsystem to improve pointing performance.