Evaluating Gazell Protocol and nRF52840DK Board for Agri UGV Control - Need Suggestions

[Sriharsha]

Hello Nordic Devzone Community,

I am currently designing a remote control system for an Agricultural Unmanned Ground Vehicle (UGV), and have some specific technical inquiries that I hope to get your insights on.

Our system has several high-level requirements:

1. Easy pairing between the transmitter and receiver: The system needs to facilitate easy and secure pairing.

2. Bi-directional, low-latency communication: The transmitter will send joystick values (under 10Hz) and button data to the UGV, while the UGV sends back vehicle parameter data for display. The communication needs to be prompt with minimal latency. My data transfer is not high at few CANbus frames/seconds

3. CAN Bus Interface: The receiver on the UGV will interface with a CAN Bus to send the received data to the various systems within the vehicle.

4. Robustness and Range: The system must be robust and have a reliable communication range of less than 100 meters LOS.

5. Multiple Vehicles: The system should handle 4-5 vehicles simultaneously in the same vicinity without interference.

6. Security: The whole system is closed and should not give access to an external party.

Currently, I am considering using the Gazelle protocol for its low latency capabilities and trying out the nRF52840DK board. In this context, I have a couple of follow-up queries:

1. Are the Gazelle protocol and the nRF52840DK board good fits for these requirements? If not, do you have any alternative suggestions?

2. Can we use NFC to trigger pairing in the Gazelle protocol? If yes, are there any particular considerations for this setup?

I would appreciate any advice, experiences, or caveats you might share to help guide our decision-making process.

Thank you in advance!

Best Regards,

[Kenneth]

Hello,

I think it's a bit difficult to give a definitive answer here, but if you don't want to use Bluetooth LE, then Gazell is a good choice both in terms of robustness and also by using Gazell pairing you get good security. You can read more about Gazell and Gazell pairing here, and also try out the example projects:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/protocols/gazell/gzll.html 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/protocols/gazell/gzp.html 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/gazell.html 

Robustness and Range: The system must be robust and have a reliable communication range of less than 100 meters LOS.

For this kind of range you will need to implement a PA, so a good start would be to get two (or more) of these development boards:
https://www.nordicsemi.com/Products/Development-hardware/nRF21540-DB 

Multiple Vehicles: The system should handle 4-5 vehicles simultaneously in the same vicinity without interference.

What do you mean by "simultaneously" here, I assume the remote will only control one vehicle at the time, so the remote would need to switch to handle a different vehicle?

There is no need to use NFC here, instead the Gazell pairing library already support proximity pairing, ref documentation: "Gazell only allows pairing when the Host and Device are in close proximity to each other. The Received Signal Strength Indication (RSSI) is used on the Host side of the nRF52 Series so that only Devices residing close (<30 cm) to the Host are allowed to pair (on the nRF24L IC Host nodes, the carrier detect functionality is employed). Proximity estimation is essential to avoid confusion when pairing in certain environments, for example in an office."

Kenneth

[Sriharsha]

Hi, 

Thank you for your reply. I have decided to go ahead and get sample boards to test out the features. Thank you for the suggestion on using PA.

Kenneth said:

What do you mean by "simultaneously" here, I assume the remote will only control one vehicle at the time, so the remote would need to switch to handle a different vehicle?

Yes, i meant that in a same location multiple ugv with its own controller can be active and working next to each other. But from my understanding, the Gazelle manages to work under such circumstances.

I have some questions regarding setting up the CANbus for which I will raise a new ticket.

Best,

Sriharsha