Messages

Messages are sent between linked Nodes. The only way nodes communicate with each other is by sending messages from one to another. On the table of contents (left side of the page) all DepthAI message types are listed under the Messages entry. You can click on them to find out more.

Creating a message in Script node

A DepthAI message can be created either on the device, by a node automatically or manually inside the Script node. In below example, the code is taken from the Script Camera Control example, where the Camera Control message is created inside the Script node every second and sent to the Camera's input (cam.inputControl).

Python

1script = pipeline.create(dai.node.Script)
2script.setScript("""
3  # Create a message
4  ctrl = CameraControl(1)
5  # Configure the message
6  ctrl.setCaptureStill(True)
7  # Send the message from the Script node
8  node.io['out'].send(ctrl)
9""")

Creating a message on the Host

It can also be created on a host computer and sent to the device via input queue. In the example below, we have removed all the code that isn't relevant to showcase how a message can be created on the host and sent to the device.

Python

1imgFrame = dai.ImgFrame()
2frame = np.ones((300, 300, 3), np.uint8) * 255
3imgFrame.setData(frame)
4imgFrame.setWidth(frame.shape[1])
5imgFrame.setHeight(frame.shape[0])
6imgFrame.setType(dai.ImgFrame.Type.BGR888i)
7
8with dai.Pipeline() as pipeline:
9    # Define source and output
10    script = pipeline.create(dai.node.Script)
11    cam_input_q = script.inputs["frame"].createInputQueue()
12    script.setScript("""
13    import time
14    while True:
15        frame = node.io["frame"].get()
16        if frame:
17          node.warn("Received frame")
18        time.sleep(0.1)
19    """)
20
21    pipeline.start()
22    while pipeline.isRunning():
23
24        cam_input_q.send(imgFrame)
25        time.sleep(1)

ON THIS PAGE

Messages

Creating a message in Script node

Creating a message on the Host