I am using an I2C bus to communicate with Grove modules, connecting a PM2.5 sensor and an LCD to the I2C and running a simple I2C scanner sketch to detect it.
Seem there is some sort of conflict and the LCD (I2C 0x3e) only responds from time to time or not at all, while the PM2.5 is listed all the time correctly (I2C 0x40). when connecting the LCD without the PM2.5, all works well and the scanner detects it at address 0x3e as expected.
These are the modules I use:
Grove - Laser PM2.5 Sensor (HM3301) - PN 101020613 (air quality sensor)
Grove - 16x2 LCD (White on Blue) - PN 104020111
Any idea what could cause this?
Hi There
maybe you can power by DC Jack. 
. I think that is about the power supply.
Thank you, I did try and powered with an external 12V power supply before, but it did recall any difference;
I will surely try again now to make sure
Double checked, connecting all my I2C devices, some are detected (e.g. PM2.5) and some are not detected (LCD).
What other leads should I check? :roll:
Hi there
maybe you can use Software I2C to enable different devices to control through different IICs. .and this is link <LINK_TEXT text=“http://wiki.seeedstudio.com/Arduino_Sof … ser_guide/”>http://wiki.seeedstudio.com/Arduino_Software_I2C_user_guide/</LINK_TEXT>.