# Sensors **URL:** https://community.purpleair.com/c/sensors/10.md [Latest](https://community.purpleair.com/latest.md) · [Categories](https://community.purpleair.com/categories.md) --- ## [Sensor Owner's Guide](https://community.purpleair.com/t/sensor-owners-guide/8170)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 7\ **Last updated:** [August 18, 2025, 7:43pm UTC](https://community.purpleair.com/t/sensor-owners-guide/8170 "2025-08-18T19:43:08Z")
Introduction Welcome to PurpleAir! By purchasing a sensor, you have joined a worldwide network of people striving to better understand their air. You can now contribute to that network by setting up your device. Doing … --- ## [About PurpleAir Sensors](https://community.purpleair.com/t/about-purpleair-sensors/74)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 2\ **Last updated:** [January 24, 2025, 1:59pm UTC](https://community.purpleair.com/t/about-purpleair-sensors/74 "2025-01-24T13:59:02Z")
This category serves as a knowledge base for information regarding PurpleAir sensors and other hardware. Here you can find information about setting up your sensor, troubleshooting, and other related topics. If you have … --- ## [Sensor WiFi and Registration](https://community.purpleair.com/t/sensor-wifi-and-registration/182)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 13\ **Last updated:** [November 6, 2023, 8:33pm UTC](https://community.purpleair.com/t/sensor-wifi-and-registration/182 "2023-11-06T20:33:08Z")
This guide will walk you through connecting your sensor to WiFi and registering it on the PurpleAir map. Please recognize that these are separate processes, and don’t need to be completed at the same time or in the sam… --- ## [Sensor Maintenance](https://community.purpleair.com/t/sensor-maintenance/1531)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 3\ **Last updated:** [October 8, 2026, 10:09pm UTC](https://community.purpleair.com/t/sensor-maintenance/1531 "2026-10-08T22:09:05Z")
This article contains information on maintaining a PurpleAir sensor’s laser counters, which collect particulate matter data. If your sensor is experiencing issues with temperature, humidity, or VOC readings, try the ste… --- ## [My sensor is not starting](https://community.purpleair.com/t/my-sensor-is-not-starting/22932)
**Author:** [@abdoulaye\_sow](https://community.purpleair.com/u/abdoulaye_sow)\ **Replies:** 2\ **Last updated:** [October 3, 2026, 12:52am UTC](https://community.purpleair.com/t/my-sensor-is-not-starting/22932 "2026-10-03T00:52:17Z")
I just plugged in my sensor; the red light is on, but the sensor isn’t starting up. What is the solution? Note: The sensor was working before the problem occurred. I can no longer see its Wi-Fi signal or the green lig… --- ## [Sensor will not save WiFi password](https://community.purpleair.com/t/sensor-will-not-save-wifi-password/8287)
**Author:** [@Fast](https://community.purpleair.com/u/Fast)\ **Replies:** 3\ **Last updated:** [September 29, 2026, 8:15pm UTC](https://community.purpleair.com/t/sensor-will-not-save-wifi-password/8287 "2026-09-29T20:15:15Z")
Had this sensor for some time, but since I changed the WiFi password, the sensor will accept it but will not save it and will not register on the purpleair network. Thoughts? --- ## [FLEX temperature and VOC units](https://community.purpleair.com/t/flex-temperature-and-voc-units/22916)
**Author:** [@OU\_livinglab](https://community.purpleair.com/u/OU_livinglab)\ **Replies:** 1\ **Last updated:** [September 24, 2026, 10:29pm UTC](https://community.purpleair.com/t/flex-temperature-and-voc-units/22916 "2026-09-24T22:29:13Z")
Hello, Is it possible to change the default temperature units on a FLEX so that the temperature that is displayed on the map, saved to the SD card and for API download to degrees celsius (˚C)? I’m using this for educati… --- ## [Correction equation for newer generation hardware?](https://community.purpleair.com/t/correction-equation-for-newer-generation-hardware/22914)
**Author:** [@heroic](https://community.purpleair.com/u/heroic)\ **Replies:** 0\ **Last updated:** [September 7, 2026, 2:42am UTC](https://community.purpleair.com/t/correction-equation-for-newer-generation-hardware/22914 "2026-09-07T02:42:54Z")
Hi all, In researching a particulate matter sensor to purchase I started heavily considering purpleair sensors. Doing a bit of research, I found the Karoline Barkjohn paper about the correction equation that can be appl… --- ## [Watch Duty claims my sensor is offline IT IS NOT](https://community.purpleair.com/t/watch-duty-claims-my-sensor-is-offline-it-is-not/22886)
**Author:** [@jim](https://community.purpleair.com/u/jim)\ **Replies:** 2\ **Last updated:** [September 2, 2026, 4:17pm UTC](https://community.purpleair.com/t/watch-duty-claims-my-sensor-is-offline-it-is-not/22886 "2026-09-02T16:17:17Z")
Watch Duty app & website shows my sensor as off line at times and complety gone at others and on line every now and them. - but an immediate check on the PA map shows it’s on line - and has been on line for days. WD says… --- ## [Discrepancy with Nearby Sensor](https://community.purpleair.com/t/discrepancy-with-nearby-sensor/22863)
**Author:** [@Shipuser](https://community.purpleair.com/u/Shipuser)\ **Replies:** 5\ **Last updated:** [August 10, 2026, 10:01pm UTC](https://community.purpleair.com/t/discrepancy-with-nearby-sensor/22863 "2026-08-10T22:01:39Z")
I have just installed a new sensor in our backyard, the location is less than 1/2 mile from an existing sensor located near the main road through our town. Our sensor reads much higher than the sensor in town: currently … --- ## [Replacement Parts Sought for 5 yr old PA-II Classic](https://community.purpleair.com/t/replacement-parts-sought-for-5-yr-old-pa-ii-classic/22855)
**Author:** [@Mike\_Cullen](https://community.purpleair.com/u/Mike_Cullen)\ **Replies:** 1\ **Last updated:** [August 3, 2026, 10:06pm UTC](https://community.purpleair.com/t/replacement-parts-sought-for-5-yr-old-pa-ii-classic/22855 "2026-08-03T22:06:32Z")
Our venerable PA-II unit has died in our coastal zone, but I’d like to try to give it a second life, if possible. Symptoms: Red LED on; 3.3 v present on control board; board looks clean no WiFi present one fan spinnin… --- ## [WiFi & Status Indicators](https://community.purpleair.com/t/wifi-status-indicators/22812)
**Author:** [@davidi](https://community.purpleair.com/u/davidi)\ **Replies:** 4\ **Last updated:** [July 30, 2026, 11:38pm UTC](https://community.purpleair.com/t/wifi-status-indicators/22812 "2026-07-30T23:38:52Z")
Hello everyone! I’m hoping someone can help me solve this. I have a PurpleAir Flex Sensor and my WiFi Connected status always stays orange and never changes to green. Sometimes I’ll see it grey colored. In the bottom-le… --- ## [SD Card Overview](https://community.purpleair.com/t/sd-card-overview/22502)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 1\ **Last updated:** [July 30, 2026, 7:26pm UTC](https://community.purpleair.com/t/sd-card-overview/22502 "2026-07-30T19:26:44Z")
PurpleAir sensors with SD logging capability (Classic and Classic Plus with SD capability, which both come with a microSD card, and Flex and Zen sensors) can record air quality data directly to a microSD card, providin… --- ## [Zen - 3 white one red](https://community.purpleair.com/t/zen-3-white-one-red/22842)
**Author:** [@CIT](https://community.purpleair.com/u/CIT)\ **Replies:** 1\ **Last updated:** [July 28, 2026, 7:39pm UTC](https://community.purpleair.com/t/zen-3-white-one-red/22842 "2026-07-28T19:39:18Z")
Any idea what’s going on with this sensor? Is it an error code? --- ## [Sensor B is downgraded, but Sensor A is stuck at zero](https://community.purpleair.com/t/sensor-b-is-downgraded-but-sensor-a-is-stuck-at-zero/22816)
**Author:** [@Gordon](https://community.purpleair.com/u/Gordon)\ **Replies:** 2\ **Last updated:** [July 23, 2026, 11:23pm UTC](https://community.purpleair.com/t/sensor-b-is-downgraded-but-sensor-a-is-stuck-at-zero/22816 "2026-07-23T23:23:35Z")
--- ## [Sensor A is downgraded, but Sensor B is stuck at zero](https://community.purpleair.com/t/sensor-a-is-downgraded-but-sensor-b-is-stuck-at-zero/21943)
**Author:** [@Gordon](https://community.purpleair.com/u/Gordon)\ **Replies:** 5\ **Last updated:** [July 15, 2026, 10:08pm UTC](https://community.purpleair.com/t/sensor-a-is-downgraded-but-sensor-b-is-stuck-at-zero/21943 "2026-07-15T22:08:04Z")
--- ## [5 year old PA-II repairable?](https://community.purpleair.com/t/5-year-old-pa-ii-repairable/2251)
**Author:** [@cjohlandt](https://community.purpleair.com/u/cjohlandt)\ **Replies:** 11\ **Last updated:** [July 1, 2026, 5:55am UTC](https://community.purpleair.com/t/5-year-old-pa-ii-repairable/2251 "2026-07-01T05:55:30Z")
Hello. I’ve been running a PurpleAir PA-II for over 5 years. About a week ago, it stopped reporting and was no longer visible on my WiFi. I unplugged it for a few minutes and reconnected. It’s now active again, but r… --- ## [Temperature sensor oscillations](https://community.purpleair.com/t/temperature-sensor-oscillations/22592)
**Author:** [@ebroder](https://community.purpleair.com/u/ebroder)\ **Replies:** 2\ **Last updated:** [June 26, 2026, 12:10am UTC](https://community.purpleair.com/t/temperature-sensor-oscillations/22592 "2026-06-26T00:10:46Z")
I have a Purple Air Zen installed outdoors, and I’ve been using the local JSON endpoint to pull data into my Home Assistant install. However, I’m seeing some weird behavior where the temperature and humidity sensors seem… --- ## [Blizzard killed many PA rh sensors](https://community.purpleair.com/t/blizzard-killed-many-pa-rh-sensors/22561)
**Author:** [@geo-allen](https://community.purpleair.com/u/geo-allen)\ **Replies:** 1\ **Last updated:** [June 25, 2026, 11:38pm UTC](https://community.purpleair.com/t/blizzard-killed-many-pa-rh-sensors/22561 "2026-06-25T23:38:53Z")
7 of my 14 PA RH sensors died around 8am on 2/23, the peak of the NE blizzard. They now are stuck at 100%. This makes the data from the EPA correction much higher than the rest of my PAs that have working RH. Will t… --- ## [2025 Plantower PMS5003 variation](https://community.purpleair.com/t/2025-plantower-pms5003-variation/22509)
**Author:** [@JayGuerette](https://community.purpleair.com/u/JayGuerette)\ **Replies:** 3\ **Last updated:** [June 25, 2026, 11:25pm UTC](https://community.purpleair.com/t/2025-plantower-pms5003-variation/22509 "2026-06-25T23:25:16Z")
I bought a new 2025 Plantower PMS5003 that is fairly consistent with 2 others purchased about 4 years ago except the \<0.3μm bin is off by a factor of 3. You reported some variations over the past years, with the most re… --- ## [wired/Ethernet connection option still planned?](https://community.purpleair.com/t/wired-ethernet-connection-option-still-planned/7838)
**Author:** [@Robert](https://community.purpleair.com/u/Robert)\ **Replies:** 18\ **Last updated:** [June 25, 2026, 11:14pm UTC](https://community.purpleair.com/t/wired-ethernet-connection-option-still-planned/7838 "2026-06-25T23:14:34Z")
Hello, Is wired connection to units, with ethernet data support, still on the roadmap for Purple Air sensors? And if so, any ETA? Last year, those answers were yes, and unknown. Thanks, Robert --- ## [Running a PurpleAir sensor off a power bank (daily charging setup)](https://community.purpleair.com/t/running-a-purpleair-sensor-off-a-power-bank-daily-charging-setup/22783)
**Author:** [@bridgetclairem](https://community.purpleair.com/u/bridgetclairem)\ **Replies:** 0\ **Last updated:** [June 25, 2026, 8:43pm UTC](https://community.purpleair.com/t/running-a-purpleair-sensor-off-a-power-bank-daily-charging-setup/22783 "2026-06-25T20:43:03Z")
Hi all, I’m based in Australia and looking to set up an outdoor PurpleAir sensor. I’ve got good WiFi where I want to place it, but no access to continuous power. Rather than setting up a solar panel and battery system,… --- ## [SD Card Troubleshooting](https://community.purpleair.com/t/sd-card-troubleshooting/543)
**Author:** [@PurpleAir](https://community.purpleair.com/u/PurpleAir)\ **Replies:** 13\ **Last updated:** [June 25, 2026, 12:13am UTC](https://community.purpleair.com/t/sd-card-troubleshooting/543 "2026-06-25T00:13:20Z")
This article’s purpose is to help you identify and resolve any issues you might be having with collecting data from your PurpleAir sensor with a microSD card. To get an overview and learn about what expected and normal… --- ## [New version of Plantower PMS5003](https://community.purpleair.com/t/new-version-of-plantower-pms5003/288)
**Author:** [@Adrian](https://community.purpleair.com/u/Adrian)\ **Replies:** 34\ **Last updated:** [June 24, 2026, 11:55pm UTC](https://community.purpleair.com/t/new-version-of-plantower-pms5003/288 "2026-06-24T23:55:15Z")
We recently found that there is a new design of the Plantower device that we were not aware of and have been supplied with lately. It has all the same markings on the outside but a new PCB on the inside. We identified a … --- ## [Sensor Issue](https://community.purpleair.com/t/sensor-issue/22772)
**Author:** [@StormChaser45662](https://community.purpleair.com/u/StormChaser45662)\ **Replies:** 1\ **Last updated:** [June 18, 2026, 10:05am UTC](https://community.purpleair.com/t/sensor-issue/22772 "2026-06-18T10:05:27Z")
PurpleAIr sensors will not connect to 5G internet speed, only 2.4G. With the networking upgrading and you are updating your internet speed to 5G, you won’t be able to connect your PurpleAir sensor to it. PurpleAir needs … --- ## [WiFi Band 2.4 vs. 5 G](https://community.purpleair.com/t/wifi-band-2-4-vs-5-g/8316)
**Author:** [@TwoTowns](https://community.purpleair.com/u/TwoTowns)\ **Replies:** 2\ **Last updated:** [June 18, 2026, 10:02am UTC](https://community.purpleair.com/t/wifi-band-2-4-vs-5-g/8316 "2026-06-18T10:02:44Z")
Our 2 sensors (indoor & outside) continue to perform great, as they have for several years using 2.4 G WiFi band. Lately, I need to use 5G band for additional, unrelated devices, but can’t due to PurpleAir’s 2.4 require… --- ## [Connecting a purple air sensor to my server](https://community.purpleair.com/t/connecting-a-purple-air-sensor-to-my-server/12738)
**Author:** [@Metron6](https://community.purpleair.com/u/Metron6)\ **Replies:** 8\ **Last updated:** [June 16, 2026, 4:40pm UTC](https://community.purpleair.com/t/connecting-a-purple-air-sensor-to-my-server/12738 "2026-06-16T16:40:00Z")
in the registration page says “To help community science and improve air quality forecasting, share your device’s location and sensor readings with The Weather Company, LLC (includes Weather Underground and The Weather C… --- ## [Weak/defective Sensor?](https://community.purpleair.com/t/weak-defective-sensor/22690)
**Author:** [@absheral](https://community.purpleair.com/u/absheral)\ **Replies:** 0\ **Last updated:** [May 22, 2026, 2:47pm UTC](https://community.purpleair.com/t/weak-defective-sensor/22690 "2026-05-22T14:47:53Z")
Over several months, I collected data using 4 sensors all next to each other and of the same model. After plotting all of the data, three of them yielded nearly identical results, however one of them measured consistentl… --- ## [Ferrite Power Supply in PA Flex](https://community.purpleair.com/t/ferrite-power-supply-in-pa-flex/22689)
**Author:** [@Marcos\_Andres\_Pineda](https://community.purpleair.com/u/Marcos_Andres_Pineda)\ **Replies:** 0\ **Last updated:** [May 21, 2026, 6:51pm UTC](https://community.purpleair.com/t/ferrite-power-supply-in-pa-flex/22689 "2026-05-21T18:51:32Z")
Good day, everyone We are deploying some PA Flex sensors city-wide, and we have some working power supplies for the PA Classic (with ferrite). Has anyone tried to use those for the Flex sensors? Or if it could damage th… --- ## [Difficulty connecting and staying connected to Wifi](https://community.purpleair.com/t/difficulty-connecting-and-staying-connected-to-wifi/10932)
**Author:** [@mwvanorder](https://community.purpleair.com/u/mwvanorder)\ **Replies:** 4\ **Last updated:** [May 16, 2026, 12:23am UTC](https://community.purpleair.com/t/difficulty-connecting-and-staying-connected-to-wifi/10932 "2026-05-16T00:23:25Z")
My sensor was working but occasionally would disconnect. I needed a new router so I installed a ZenWifi AX3000 mesh network. It gives a very strong signal to the sensor on the 2.4GHZ band. I got the sensor connected b… [Next page](https://community.purpleair.com/c/sensors/10.md?page=1)