[AB01] I2C failure after long time (?)

#1

Hi all,

I have a sensor which has been working fine for 8months … suddenly I couldn’t read data over I2C anymore (sensor was inside an IP68 box, no leaks, box inside is clean and had conformal coating on the board for humidity).

so I loaded the I2C scan test program and using I scope I can see that SCL is always HIGH, I do not see the clock coming out.

SDA is always “low” of course.

I do have pullups (4.7k) on both lines.

===
I’m a little scared by such a failure because I have no way to debug. This is a sensor with a BMP280 and SHT20 attached on I2C, nothing more.
Sensors are turned on/off each (using Vext) each time there is a read.

So the question is about “reliability” … anyone on this forum that had a similar failure over time??

system is working just fine, nothing else is broken, LoRaWAN works perfeclty … just I2C does not work.

any hint/help to debug is much appreciated.

thanks

#2

BTW: since the pullup on SCL is keeping the line “high” with the “i2c scanner” app I’m confident that the issue is NOT on the sensors itself …

if it was an issues on the sensors I should at least see the SCL line pulled down from time to time, isn;t it?

#3

hi,

Could you try the IIC scanner(Connect the sensor):
https://github.com/HelTecAutomation/CubeCell-Arduino/blob/master/libraries/Basics/examples/I2C/i2c_scan/i2c_scan.ino

#4

yes, this is the “I2C scanner” I used to test if the port was working or not.

when I run the example there is no clock on SCL, the level is HIGH all the time … no clock is coming out of the AB01.

thanks

#5

In my experience the hardware is flaky. I have two boards and each failed in its own way after a few weeks. One would stop charging the battery, whether via USB or via solar. The other one stopped communicating correctly via I2C and can’t get proper reading in the simplest of setups (forget about putting two sensors on the I2C bus).

If you can’t get I2C going on a brand new board at all, there were some bleeding edge updates to the protocol implementation (HTCC-AB02S Problem 2 I2C) that you could try but if things stopped working after a while, my guess is the HW went bad.

#6

Yes! I have 4 AB-01 right now no one alive. I2C fails charge fails etc…
No one!!! I give up to find another.

06
截圖 2021-04-27 下午6.40.06.png528×1272 45 KB

#7

This thread is scaring me. I have a lot of AB01 on the field using I2C and also RS485. They are working fine till know, but the first one was activated only 2 months ago.

Is this problem something really common? Should we take in consideration something to avoid this in long time?