Faulty Pi CM4 on Dexi - Need replacement ASAP

Hi, we were recently doing some testing related to IR and April tags with our DEXI and noticed that we would lose connection to our DEXI when it got farther than 10 feet from the connected laptop. We’ve done extensive testing and troubleshooting in an attempt to fix this issue, with no effect on our Wi-Fi range.

How we tested the Wi-Fi range

To test the Wi-Fi connection range, we took the same steps every time: We had the DEXI LEDs constantly loop between red and blue using NODE RED. Since the DEXI commands are handled on the client of the connected laptop, connection issues or a connection break would be denoted by the LEDs locking up for several seconds at a time (temporary connection loss) or freezing entirely (connection break). I would slowly back away from the controlling laptop, noting the distance that the LEDs started malfunctioning. After passing the connection break distance, the controlling laptop had to reconnect to the DEXI Wi-Fi in order to send commands again.


Troubleshooting Process

We’ve tried the following troubleshooting methods:

  • I have personally verified that the drone is configured to use the external antenna correctly. This is corroborated by the fact that unscrewing the external antenna from the drone causes an immediate disconnect, even if the drone is right next to the connected laptop.
  • I’ve switched out the antenna (the removable part) for a much larger one. Despite being comically large, the drone still disconnected at the 10 foot mark of the distance test. I’ve attached an image below for your viewing pleasure.

  • We used an entirely different laptop to conduct the test. I did the NODE-RED setup process on my machine, and copied the code that my DEXI programmer had used for testing. Again with the distance test, the results did not change at all. The LEDs would flash back and forth until I got 10 feet away from the controlling laptop, and then they would become laggy and eventually freeze completely.
  • Since our school has two teams that are participating in this year’s competition, I have the privilege of having access to another DEXI. We connected their DEXI to our laptop, conducted the test, and I got fully outside of our robotics lab and about halfway down the hallway before I gave up on trying to determine the range of their DEXI.

As a result of our troubleshooting efforts, I’ve determined that the issue lies in a faulty Pi CM4. @droneblocks if you could help us get a replacement component, we would really appreciate it.

Our team’s first competition is November 9th, and I’d like to receive the replacement as soon as possible so that we can properly test the scoring capability of our DEXI before the competition.

Hi Max,

Please verify that the antenna cable is securely connected to the Pi. Additionally, please inspect the cable for any visible cuts or damage.

If this all checks out please reach out to support@droneblocks.io

Thanks,
Ryan

Just checked - no dice. The connector is undamaged and I’ve verified that the connection to the CM4 is solid. I just sent an email to support@droneblocks.io!

Thanks for checking, we will get it sorted out as fast as possible.

Thanks,
Ryan

Hey Ryan, I just sent out a follow-up email to support@droneblocks.io from a different address. My email has been acting up as of late, and it’s likely that y’all never received the original email. Let me know if you get this one!

Thank you so much for your quick responses on this matter!

FYI we received your support request and I know @Ryan_DroneBlocks is working to get you a replacement.

We received the new CM4, installed it, and it works perfectly! Our DEXI range has easily quadrupled.

I’ll make sure to get the faulty CM4 mailed to y’all ASAP.

Thank you!

Thanks for getting back to us. Please do send it our way so we can notify the manufacturer. Let me also add that you guys did a great job of analyzing the issue. Well done!