Raising awareness about air pollution one city block at a time.

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Air polution is a silent killer. It's invisible, only mildly annoying and yet it contributes to early deaths of millions worldwide. We feel that the first step towards tackling this problem is raising awareness about it. One way of doing that is to make it painfully visible how prevalent the problem is. We will accomplish this by deploying a massive network of inexpensive air pollution sensors capable of displaying air pollution in their immediate area via visual means - bright LEDs.

We have designed a sensor which anyone can build, or manufacture en masse - the first revision is readily available from our github repository. We're currently working on adapting our prototype firmware to propel this first revision, which should be available shortly.

We're using a range of inexpensive and readily available PM sensors - PMS3003/5003/7003 and SDS011. All parts are easily sourceable and the sensor can be build by anyone with basic soldering skills.

We envisage that these inexpensive sensors can be built and maintained by interested hobbyists. Our goal is not to develop the world's most accurate sensor, but rather a device which at a glance tells us if it's a good idea to spend time outside.


Electronic schematics.

Adobe Portable Document Format - 259.35 kB - 04/22/2018 at 16:20


Gerber files suitable for manufacturing.

Zip Archive - 122.62 kB - 04/22/2018 at 16:19


  • 1 × Plantower PMS3003/5003/7003 Laser particular matter sensor with a serial interface
  • 1 × ESP-12F ESP8266-based embedded WiFi module
  • 1 × HTU21D Sensors / Temperature, Thermal
  • 10 × SMD RGB LED
  • 2 × SMD TACT

View all 7 components

  • PCB redesign - rev2

    Jan Szumiec07/16/2018 at 12:51 0 comments

    The PCB has been redesigned - we've decided to use SMD parts which can be placed using a pick-and-place machine and left the LEDs to be assembled by hand. This makes it easy to turn it into a DIY kit which doesn't require a huge amount of soldering - just the LEDs. With this redesign, we've addressed the PWM issue - we can now display the whole color spectrum using generic RGB LEDs.

  • Si7021 now supported as an environmental sensor

    Jan Szumiec05/07/2018 at 20:40 0 comments

    I've added support for another inexpensive environmental sensor - the Si7021. It is pin-compatible with the HTU21, so you can use both interchangeably. The software will automatically detect and report which sensor is attached upon startup.

  • Slight rewiring required to get PWM to work

    Jan Szumiec05/02/2018 at 13:19 0 comments

    We've discovered that there's a problem driving our LEDs via PWM - the library we're using doesn't let us use GPIO16 as a PWM pin. We think the best way to solve this would be to rewire the pins around a bit.


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Rud Merriam wrote 07/05/2018 at 21:42 point

Where's the software?

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Jan Szumiec wrote 07/06/2018 at 13:29 point - still working on the server side component.

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Jan wrote 05/02/2018 at 18:41 point

Nice project! But on the down side it's really embarrassing for us mankind that we feel the need to build a sensor network to tell us when it's a good idea to go outside!
By the way, there are whole air-quality networks in existence already, like

India was in the news today as well for the worst possible air quality

Would be interesting to compare your findings with data from an existing network!

Best wishes, Jan

EDIT: And congratulations to your prize (

Well done!

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