I’m a student of the Maritime University. As members of the university science club, we are doing our first major project. We would like to use Herelink in this project to control an unmanned hovercraft. As we are still learning how to program and use such electronics, I have a few questions before buying to be 100% sure.
We have an idea to use Herelink to send control signal to Raspberry Pi. All we need is to receive an image and send a signal about which joystick or button was pressed, the rest of the control of hovercraft is to be done by the Raspberry.
We think about this method of use:
Pressing the button on the Herelink Controller> signal sent to the Air Unit> from the Air Unit via the UART connector (Is that a good way?) send information to the RPi about which button was pressed> from Raspberry further control
And send video from RPi through Air Unit to Controller
Could it work like that?
Can we use Herelink without The Cube Orange and without Pixhawk? Currently, we don’t need an autopilot and GPS (we’ll have an automatic identification system (AIS) as a GPS transmitter required for ships).
Do you have any advice for beginners about connection Herelink with RPi?
Thank you for your help and sorry for linguistic mistakes
Think Herelink only as a transmitter / receiver radio control device …
If you are looking for a 4g connection between Hoover and GCS , there is a tutorial link where you need to connect RasPi to a flight controller like a Pixhawk variant and then by creating a Zerotier account to take care of the VPN network for you. In this case you need to install Zerotier on Raspi and a Zerotier client on the GCS( PC and maybe Herelink as Zerotier supports Android) . . What this does is to keep the drone( having the Raspi companion computer ) and the GCS in the same network as with Zerotier. Ofcourse u have to use a USB modem on the RasPi as well for internet connection !
I am also curious to understand how you plan to waterproof the components if the drone is Hoover
Alternatively maybe the following link can assist you too
GUIDED mode How to see the MP's raw Mavlink RC commands IN and OUT? - #3 by Michael_Oborne - Mission Planner - ArduPilot Discourse
My reply here may be out of your query …
Thank you for your reply. We would prefer to avoid the 4G connection as the hovercraft can be used in places where there is no internet coverage. Therefore, we would prefer to use HereLink as a remote communication tool for video and control signal to Raspberry Pi. I just need to confirm if there will be no problem with connecting the Air Unit with RPi and if UART is the right way.
In terms of water resistance, the whole thing will be sealed inside the hovercraft, only the antennas will be outside. It will be a large hovercraft, over 3m long.
My immediate thought is if you cannot get a 4G signal in such remote places, what is the guarantee a radio FSK signal can reach to those places. This is just a thought . You may be right
Also i haven’t read anywhere in this forum that the Air unit can be programmed by the user for such UART connections. So this is the case where we use the flight controller to do the UART thing…
Also incase you do a test by your direction of having airlink connected to a RasPi, you need to check the voltage levels either 3.3V or 5V.( link to level shifter if required RPi Serial Connection - eLinux.org ) .
And also since Mavlink messgaes can be send by Herelink through " Mavlink console" , there may be a possibility as per your query.
There are various way to do this.
The Sbus way
Connect the second sbus to your raspberry pi so it directly receives signal from Herelink
The mavlink message way
Connect you raspberry pi to mavlink network. When Herelink sends signal through mavlink button, it propagates through the network.
The lua script way
Program a lua script on Cube to react after receiving sbus signal or mavlink signal from Herelink.
Herelink can work alone without the autopilot, as long as you have way to proceed the signals.
Great feedback!! just an additional query…can we use simultaneously both the sbus ports during flight…
That should be fine. You can check it from Herelink App > Joystick outputs or actually connect something.
I was looking for an option to send python scripts to a Rasberry pi mounted on a drone with cube orange from my pc via herelink telemetry or any other radio telemetry. From your reply it looks like it can be done. Am I right ? Can we send python scripts on the pi with herelink telemetry. If so, is there any detailed tutorial or documentation for the same. I’ve been looking for this solution for a long time. Your help is deeply appreciated.
I have not seen a detailed tutorial on how to go about it. Probably the forum admin Alvin can guide you on this topic.
If i reach somewhere on this topic in future, i will post it here.