Read rc signal from mavlink to raspberry

Ground Control Software MAVLink
1

hi,

Could anyone help with subject as below.

What’s the easiest and most raible way to read rc signal from mavlink to raspberry?

2

You can use pymavlink to get the RC signal from mavlink data sent to the raspberry pi.

Messages (common) · MAVLink Developer Guide - Check this for more details

3

Hi,

Thanks for the replay. i have looked at these documentaction and now i have a nother problem. how to create conection in the program. i hve the connection in terminal but i want to create it in the script.

4

Below is the Python script that will establish a connection with the drone and prints the heartbeat message.

from pymavlink import mavutil

# Connect to the vehicle (modify the connection string as needed)

connection_string = input("Enter protocol, ip and port in this format 'tcp:192.168.2.202:20001': ") # Change this to your specific connection string

mav = mavutil.mavlink_connection(connection_string)

# Wait for the heartbeat from the drone to ensure a successful connection

mav.wait_heartbeat()

print(f"Heartbeat received, System_ID: {mav.target_system} Component_ID: {mav.target_component}")

You can refer to the page for more details.

5

Ok. so i’ve tried to establish the connection.in the script but received message :

File “/usr/lib/python3/dist-packages/serial/serialposix.py”, line 268, in open
raise SerialException(msg.errno, “could not open port {}: {}”.format(self._port, msg))
serial.serialutil.SerialException: [Errno 2] could not open port : [Errno 2] No such file or directory: ‘’

That means that there is no device? MAVlink is connected to raspberry by usb cable.
Connection string :“–master=/dev/ttyACM0, baud=57600”
when i type it in terminal it works and connects.

6 
from pymavlink import mavutil

# Connect to the vehicle (modify the port and baud rate as needed)

serial_port = input("Enter serial port in this format '/dev/ttyUSB0': ") # Change this to your specific connection string
baud_rate = int(input("Enter baud rate: "))

mav = mavutil.mavlink_connection(serial_port, baud=baud_rate)

# Wait for the heartbeat from the drone to ensure a successful connection

mav.wait_heartbeat()

print(f"Heartbeat received, System_ID: {mav.target_system} Component_ID: {mav.target_component}")

Try if this works…

7

Thanks for the help.

The connection is working. Now i want to read the rc channel values. So far i whose able to read all chanels using command

print(olaf.recv_match(type=‘RC_CHANNELS’, blocking=True))

the result:

RC_CHANNELS {time_boot_ms : 3978116, chancount : 8, chan1_raw : 1498, chan2_raw : 1500, chan3_raw : 899, chan4_raw : 1498, chan5_raw : 1553, chan6_raw : 1498, chan7_raw : 1498, chan8_raw : 1498, chan9_raw : 0, chan10_raw : 0, chan11_raw : 0, chan12_raw : 0, chan13_raw : 0, chan14_raw : 0, chan15_raw : 0, chan16_raw : 0, chan17_raw : 0, chan18_raw : 0, rssi : 255}

Is there a way to read individual channels? Eventually how to split show results.

8

Below code will split and show the results for individual channels:

rc_channels = olaf.recv_match(type='RC_CHANNELS', blocking=True)

print(f"Channel 1: {rc_channels.chan1_raw}")
print(f"Channel 2: {rc_channels.chan2_raw}")
print(f"Channel 3: {rc_channels.chan3_raw}")
print(f"Channel 4: {rc_channels.chan4_raw}")
9

Thank You,
i got every thing working now. Some issue with lag on servos but that’s another topic.

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