Multiple Si7021 with the same address?

Hello I was wondering if there was some way of getting multiple si7021 temperature sensors that uses the same address to work in a Arduino? I have seen two i2c screens once with the same address working. The only problem is I do not know how that works but what I would need to make it work. Can someone help me out please?


You have almost 2000 posts, and you still want me to be your Google-link-finding-service :confused: and you forgot to tell which Arduino board you use :o
Can you give a link to the module that you use, because it is a 3.3V sensor.

Manufacturer's page of the Si7021: Si7006/13/20/21/34 I2C Relative Humidity and Temperature Sensors - Silicon Labs with datasheet.

It does not have an address pin.
I did not read in the datasheet that its I2C address can be changed.

There are a few options:

  • With a analog multiplexer, only SDA needs to be multiplexed.
  • With a I2C multiplexer chip. Some chips can do level shifting at the same time.
  • With a software I2C library, the SCL pin can be shared for the multiple soft I2C busses.

I believe I answered this on another form a few days ago. Use a I2C multiplexer / bus expander.

Hello Koepol Thank you so much for shaving me from that very hard google search. It scared me to figure out what I need to figure out. Okay maybe i forgot something. I did do a google search but i wasn't and unsure of is the i2c addressing problem for the si2071 temperature sensor having the same address or no address and if there a way of addressing them or how would this work. I never did a project where they are all the same sensor before having multiple of them. That is why I'm here.

Yes I'm sorry i forgot to tell which board I'm using. I only at the moment a arduino uno and a arduino zero board. Also i never heard of a mutiplexing chip for i2c before. I know of shift registering things. I have done one project like that in the past. I did some research last night on i2c and how to switch from one sensor to another then I came across something called TCA9548A I2C Multiplexer Looks promising. Thank you. I was a little confused on what i would need to make this work. Also thank you gilshultz I never heard of into now a i2c mulplexer / Expander. This is something way new to me.


This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.