## Choosing Sensors Often the first step is to look for a sensor for what you're hoping to measure. In the community posts below, we're collecting info on different kinds of air quality sensors, and their: * cost * sensitivity/accuracy * links and documentation Can you afford a sensor? Can it detect what you're looking for? Where can you learn more about it? ### Posts about choosing and evaluating an air sensor [notes:grid:air-sensor-eval] ### Expected ranges and useful detection limits for pollutants of interest This [table](https://www.epa.gov/sites/production/files/2016-06/documents/air_sensors_webinar_slides_06-29-16.pdf) from an EPA [Air Quality Monitoring and Community Science webinar](https://www.epa.gov/sites/production/files/2016-06/documents/air_sensors_webinar_slides_06-29-16.pdf) lists the six criteria air pollutants and a couple additional pollutants, with background levels you might see in the environment in the “Range to Expect” column and useful detection limits for sensors. **** ## Wikis about air sensors [wikis:air-sensors] ## Air sensor projects Public Lab pages and posts tagged `air-sensor-projects` will appear here [nodes:air-sensor-projects] ## Questions [questions:air-sensors] ## Further reading and resources + Environmental consultant Tim Dye’s “[4 questions to ask before buying an air quality sensor](http://tdenviro.com/wp-content/uploads/2017/09/4-questions-when-buying-air-sensors.pdf)” neatly summarizes what to consider when choosing an air sensor. + [Snuffle.org](http://www.snuffle.org/): lots of information on low-cost sensors for various air pollutants. + [Air Quality Sensor Performance Evaluation Center (AQ-SPEC)](http://www.aqmd.gov/aq-spec/evaluations): from the South Coast Air Quality Management District, this program tests and evaluates air sensors “in the field, under ambient conditions, and in the laboratory under controlled environmental conditions.” + [Air Sensor Toolbox](https://www.epa.gov/air-sensor-toolbox): from the US Environmental Protection Agency, this toolbox includes guidance on how to use air sensors and their data, plus information on sensor performance and evaluation results. ...
Author | Comment | Last activity | Moderation | ||
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liz | "Email me liz@publiclab.org, if u can " | Read more » | over 6 years ago | |||
liz | "Hi @kinasmith this is extremely helpful! I have some additional information to report: the HCHO meter has already been sent to the research site in..." | Read more » | over 6 years ago | |||
kinasmith | "sorry, I wasn't very clear in that previous message. I'll try to clarify. You'll need an Arduino in the middle between the sensor and the computer...." | Read more » | over 6 years ago | |||
liz | "Can someone (@kinasmith ?) do a quick screen recording with CoolTerm open while talking about what menus and settings are needed to actually make ..." | Read more » | over 6 years ago | |||
liz | "Here's what the interface looks like: " | Read more » | over 6 years ago | |||
liz | "^^ interesting! A whole new angle on this problem. I think I would actually do this first to see the results coming out of the sensor, whether or n..." | Read more » | over 6 years ago | |||
liz | "ok thanks @cfastie and @kinasmith, i think i get it now! " | Read more » | over 6 years ago | |||
yamanoorsai | "In fact, if the analog output is linear, I would not need the meter " | Read more » | over 6 years ago | |||
yamanoorsai | "Hello, I would be glad to help as long as I get to share my work under an open license with everyone. How does one gain access to the HCHO meter li..." | Read more » | over 6 years ago | |||
kinasmith | "so, how long will the sensor need to collect data for? If there is reliable power, and it's inside of a house, and it isn't running for weeks on en..." | Read more » | over 6 years ago | |||
kinasmith | "I've read through the datasheet/manual for this sensor. Their use of audio connectors for signal and power connections is pretty questionable, but ..." | Read more » | over 6 years ago | |||
cfastie | "Liz, I don't know the specs of the 1/4" phone plug, but it needs only two contacts, the tip and one ring along the shaft. I'm not sure which types ..." | Read more » | over 6 years ago | |||
warren | "Thanks to all the software contributors who helped fix that -- @siaw23 @sagarpreet " | Read more » | over 6 years ago | |||
warren | "OK - links and uploads now working again on the site! " | Read more » | over 6 years ago | |||
liz | "wow awesome! @cfastie sorry to ask more but can you draw a picture on paper of what you expect these cables to look like? "A 1/4" stereo/phone plug..." | Read more » | over 6 years ago | |||
zengirl2 | "@cfastie @warren ah, ok that makes sense now. " | Read more » | over 6 years ago | |||
warren | "https://gist.github.com/jywarren/599b76ef9cdecdce764a7348f728ae31 " | Read more » | over 6 years ago | |||
warren | "We're still struggling with a comment formatting bug -- apologies -- over in https://github.com/publiclab/plots2/pull/2605 -- here it is for the ti..." | Read more » | over 6 years ago | |||
cfastie | "New answer below where I could attach a file. " | Read more » | over 6 years ago | |||
cfastie | "A 1/4" stereo/phone plug connects to the HCHO sensor and two wires from that cable connect to the Arduino (tip of plug to A3, ring to GND). Below (..." | Read more » | over 6 years ago | |||
zengirl2 | "@liz I can meet with @nshapiro with some Arduinos, but I think my question is where do you attach alligator clips or wires for testing this beast? " | Read more » | over 6 years ago | |||
liz | "Perhaps @Zengirl2 can go over the Nick's house and bring an Arduino? (They are both in Philly) and for good measure we can open up a video link wit..." | Read more » | over 6 years ago | |||
cfastie | "The first step might be to arrange for the co-location of the HCHO sensor, an Arduino, and somebody casually familiar with Arduino. Has the proper ..." | Read more » | over 6 years ago | |||
liz | "Hi @cfastie -- thank you so much for asking these questions. Here's what i know -- Nick has to go to Georgia with a working solution in 2 weeks...." | Read more » | over 6 years ago |