SLAM visualization with MQTT

slamviz-mqtt.py

# At the MQTT Transmission side

    data2Transmit = np.array([x, y, theta])

    # Map which is saved as a bytearray is appended at the end
    if scan_count % 30 == 0:
        client.publish("safetycam/topic/slamviz", \\
                           data2Transmit.tobytes() + mapbytes)
            
# At the MQTT receiving side

    # As 3 float values takes 8*3 = 24 bytes
    robotPos_bytes = msg.payload[:24]
    map_bytes = msg.payload[24:]

    robotPos = np.frombuffer(robotPos_bytes, dtype='float64')
    robotPos = np.array(robotPos)

    x, y, theta = robotPos
    viz.display(x / 1000., y / 1000., theta, map_bytes)