SI 7021 support - temperature and humitidy I2C


Please consider adding I2C SI 7021 support for temperature and humidity to use for monitoring, green houses, and humidors. For a work around I may be able to use a DAC fed back into a supported ADC with cayenne but native support would be awesome.


If you have a Arduino with ethernet or a ESP8266 you can put your hygrometers on Cayenne now utilizing the Cayenne virtual pins. Here is a capture of the overview screen from one of my 8266’s with both a DHT21 and a BME280 installed showing the comparisons of the output of each sensor side by side.

Here is a photo of the setup showing the 8266 and both sensors on the same breadbaord.

The addition of Arduino micro-controllers and virtual pins has really expanded the list of available sensors exponentially.


Here is a pretty good comparison of available hygrometers-


I have a Pi 3 B. Maybe I should have got the one you mentioned. I was hoping for a module for the PI to make things simpler. I will check and see how much the arduino you are talking about runs.


The Arduino schematic is open source so you can get a “knockoff” Arduino for ~$10 on ebay or amazon. Some things may not work as expected based on the actual components used but you can’t beat the price.


Yep, so as @Ian mentioned, there are many possibilities with Cayenne’s new Arduino integration. we will be working on ability for you to bring a sensor (for the Pi) that is not currently supported into the Cayenne dashboard. Unfortunately, we do not have resources to do ‘one-off’ integrations for every sensor requested. Unless of course there is MANY community members who request it (like DHT11 post). Of course, when one community member is able to integrate a specific sensor to Cayenne, then we will create process to make that available to community as a whole. This is what we have begun working on :slight_smile: I hope this explanation helps! (Adding @ats1080s for context)



Ian had a pretty good comparison of sensors if there will be only one that works. Im up and running in Java so I will create a logger from there and maybe kater integrate onto a web site. I ordered some of the DS18B20 for now, I need 3 for this project and can use cayenne for that at least until I branch out and understand this virtual pin business. Thanks for the responses, check the link Ian kindly provided and consider the SI7021 over the DHT.