# Issue with Using PMS7003 and ENVEA NO2 Sensor Together on ESP8266

**URL:** https://forum.sensor.community/t/issue-with-using-pms7003-and-envea-no2-sensor-together-on-esp8266/4287
**Category:** Uncategorized
**Created:** [January 22, 2025, 2:34pm UTC](https://forum.sensor.community/t/issue-with-using-pms7003-and-envea-no2-sensor-together-on-esp8266/4287 "2025-01-22T14:34:15Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![Bazinga](https://forum.sensor.community/letter_avatar_proxy/v4/letter/b/34f0e0/32.png) [@Bazinga](https://forum.sensor.community/u/Bazinga)
#### Post date: [January 23, 2025, 9:31am UTC](https://forum.sensor.community/t/issue-with-using-pms7003-and-envea-no2-sensor-together-on-esp8266/4287/5 "2025-01-23T09:31:12Z")

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Thanks for your answers  
I know that the cairsens is not supported in the project, and thanks to @pjg in this [topic](https://forum.sensor.community/t/supported-no2-sensors/2648/12) I was able to modify the sensor firmware that works with my No2 sensor. Now when I add the PMS7003, I use the original pins (D1 and D2) and for my cairsens I use pins D5 and D6, impossible to have the PMS data but it does not crash my eps8266 and I recover that of my No2.  
I have the impression that the PMS communication is too frequent, I can not manage its timing. I would like a little more explanation about the management of semaphores @pjg ?  
Or some track to recover one measure then the other and so on?

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