This sounds like a known issue with both versions of these breakouts that causes a small number of them to fail after passing our QC tests. Just to confirm there is no problem with your connections, can you please take a couple of photos of your board and the circuit(s) you have it in with the ESP8266 and the Pi? Please do your best to make sure they are clear and well-lit. Once we rule out any connection issues or other minor problems, we’ll be able to identify if this is the known hardware issue and move forward from there.
I recently bought sparkfun MLX90640 board , i am facing the same type of issue where i am getting i2cdetect response from all address from MLX board. I have verified the connection status and all. Looks MLX SDA line is always showing LOW even though pull up resistor is high.
Could you share me why this behaviour is happing with sensor, why it is holding the line always (restarting MLX sensor board doesn’t help).
Just for your information, thread necromancy like this is generally frowned upon. We ask that users post a new topic for any questions or issues NOT directly related to the topic. Since this is the exact issue the other user had, we will tolerate it for now but please, in the future, do not reply to already-created topics unless you either have helpful input to provide or the identical problem as the Original Poster.
Now, for your issue, this is a known hardware defect that causes the short under the sensor. You could attempt to repair it by removing the sensor, cleaning it and replacing it but it is not recommended. If you purchased the MLX90640 Breakout directly from SparkFun, please fill out the form on [this page and in the “Why do you want an RMA?” box, type in a brief description of the issue and link to this forum thread.](Return Policy - SparkFun Electronics)
