Nano 33 IoT USB + resets issues

[felipebay]

Hi!
I haven't used Arduino in a while... I used it a lot around 2013 (Arduino and Particle (then called Spark)

I'm doing a small project to measure the level on two water storage tanks that I have but I run into some issues even before attaching sensors. I have two nano 33 IoT that behave somewhat differently, I soldered the headers on one (lets call this one A) and not on the other one (B).

"A" struggles with communication thru USB to load new code and it's very difficult to put it in the programming mode (pulsing led). When I load a program successfully it runs intermittently, looses communication with the cloud and seems to reset itself. I'm not sure if it's a memory leak or something like that. I also had to update it's WiFi Nina firmware because at some point it seems it reverted to 1.2.3

When I run into the issues above I decided to test out the other unit "B", I have no issues with the USB to load the new code even when it's running, I don't even need to put it in the pulsing led mode (same code that I tried with A) and it stays online running continuously (same code, so the memory leak might not be in my code).

I did notice that one small demo code that I made to rule out memory leak on my code with "A" which involves LED_BUILTIN turns on the led on unit "A" (the one with problems) and not on unit "B", which seems weird as it exactly the same code on the same model.

I'm not sure if soldering the heads on "A" might have damaged something but to me it looks like an ok soldering job (picture attached). And it wouldn't explain why "B" with is in out of the box condition would not work correctly with led_builtin as "A" does.

If anyone could share their two cents on the above it would be greatly appreciated!
Thanks in advance!

[Klaus_K]

Welcome to the forum.

Debugging these kind of problems is fairly difficult without the right equipment and knowledge. Here are a few tips that may be helpful.

• Try another USB cable. The shorter the better. Many user found that to be an issue after being skeptical first. Make sure it sits nicely when plugged. Electrical issues with the plug are hard to test without equipment.

• Try another USB port on your PC/laptop or power the device from a USB power bank.

• I you have some measuring equipment you can measure the supply voltages and with an oscilloscope you can have a look at the signals.

• Regarding communication loss, write your code in a way that it can recover. Test the communication on the application layer and restart everything when necessary. Many users with WiFi issues have Fritzboxes. With proper recovery procedure you can have your device run for many month.

• Soldering your device can damage it. Next time do a out-of-the-box test first. Avoid soldering pins next to each other in short sequence to avoid local heat spots. You can also damage pins with ESD. This depends a bit on your environment (dry air and carpets are not good).

• The Arduino Nano 33 IoT has native USB. Your sketch can make the USB misbehave. Test simple sketches when you have USB issues.