Introducing PACMAN

What is PACMAN?

Particles, Activity and Context Monitoring Autonomous Node.

What is it for?

PACMAN was designed for indoor air quality studies. It uses low-cost components so that large numbers can be made and deployed. This gives the flexibility to instrument multiple rooms, or monitor multiple sources. Alternatively multiple homes can be studied simultaneously.

What does it do?

It continuously measures levels of certain airborne pollutants (as of version 5 the PACMAN measures dust and carbon monoxide). But it also carries other sensors chosen to provide additional information which give clues about the source of the pollution. The current version (5) includes motion and CO2 sensors to detect the presence of people in a room and respiration/ventilation rates, temperature sensors to detect heating/cooking sources and monitor human exposure to heat/cold, and a rangefinder to identify specific movements or activities within the unit’s field of view.

Where and when can it be used?

PACMAN was designed for use in the home. It is small, silent and unobtrusive. We have found that it can be easily fixed to a wall or ceiling without permanent fixings. The current version (5) requires mains power, but conversion to battery power should be simple.

How do you use it?

The unit has a single on/off switch. That’s it! Data is recorded as text files to a Micro SD card. The current version (5) allows more than 160 days of 1-second data to be stored on a 1 GB card. More information here.

Who designed and built it?

PACMAN is the offspring of proud dad Gustavo Olivares of NIWA - the National Institute of Water & Atmospheric Research, Auckland, New Zealand. (email)

Is it any good?

The NIWA Air Quality team are undertaking a range of tests. The figure below left shows the dust sensor response to frying olive oil, alongside data from a TSI AM510 “SidePak” monitor. Below left is an example trace of dust (red), CO2 (green) and movement (blue) from the kitchen of a test home.

For further details, see our paper presented at the Healthy Buildings 2012 Conference in Brisbane [draft manuscript here].

Has it been used ‘in the field’?

Some small-scale controlled tests have been conducted in the developers’ own homes. We plan to gradually expand the use of PACMAN into volunteers homes through late 2012 and early 2013, leading to a full-scale experiment in mid 2013.

What developments are in the pipeline?

We have plans to adapt the unit for outdoor use including adding battery power and solar charging. Additionally, we would like to add nitrogen dioxide and humidity sensors. The dust sensor is a crucial unit and we will be keeping an eye on developments in improved sensors.

Can we have one to play with?

That’s very possible. The system was designed and developed within an open source paradigm and as such the firmware is released under the LGPL and the design files under the Creative Commons Share-Alike license. The idea is that the more people get to play, the more brains can be applied at improving it. Please get in touch with Gustavo (email), Ian (email) or Guy (email) at NIWA to discuss.

Can you give me more technical details?

You can check out the User Guide, or more technical data including the firmware and design files here.

Specifications

Weight

270 g

Dimensions

100(L)x100(D)x80(H)mm

Power consumption

~300mA@9Vdc

Working temperature

Uncertain. At the time of writing it had been tested between 10°C and 50°C

This document was last updated on 31st July 2012 by Gustavo Olivares.