Saturday, August 1, 2015

AMQUMO: A Xively AMbient QUality MOnitor built on ATmega328

AMQUMO is an Indoor AMbient QUality MOnitor.

AMQUMO logs 4 environmental parameters:
  • Humidity
  • Temperature
  • Ambient Noise
  • Brightness

The data it is logged to the platform, and displayed to the user through 4 bi-color leds.

It can be used to monitor you Office Ambient Quality over the parameters logged.

This project it is built upon the xively logger ATmega328 library:

So, a web page can be used to setup network parameters, and xively tokens.
Network can be set using a Static IP, Gateway, NET Mask, or DHCP.
Obviously xively feed number and API token can be setup by that web page.
Also the temperature sensor library expose a Celsius/Fahrenheit settings here.

EC28J60 board perform all the communications.

For humidity and temperature a DHT22 sensor it is used.
To measure ambient noise an analogic noise sensor built with a electret microphone and a opamp it is used.
Brightness it is measured by a BH1750 sensor board.

Ambient noise and brightness are sampled 2 times per seconds, in order to give the led feedback almost instantly. Humidity and temperature have slower samplerate.
Ambient levels average it is computed and then posted to every minute.

All that parameters can be changed at compile time by user.
Also it is quite simple to add your own sensor.

The PCB is quite simple, it's just a bridge board for a low cost Arduino Mini board and all the sensors board.
The main board and all sensor can be of course designed as a single board.
Note that the temperature and humidity sensor needs to be exposed outside the main electronics board, because both the EC28J60 chip and the voltage regulator heat up to almost 40 deg. and 
To solve this issue, a step down switching regulator should be used. And eventually another networking solution.

As references for optimal ambient threshold, some international standards and papers are taken in consideration.
  • Helsinki University of Technology: Effect Of Temperature On Task Performance In Office Environment [Olli Seppänen, William J Fisk, QH Lei]
  • ASHRAE Standard 62.1-2010
  • VAISALA - Increased human comfort from optimal indoor air humidity
  • University of Nebraska - Relating Productivity & Annoyance 
  • to Indoor Noise Criteria Systems: A Low Frequency Analysis [Erica E. Bowden & Lily M. Wang, Ph.D.]
  • Noise in The Office Workplace [Lorraine E. Maxwell]
  • Labour Department of HK - Lighting In Offices


  • read risk disclaimer
  • excuse my bad english

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