Document Type

Closed Project

Publication Date

Winter 2012


Timothy Anderson

Course Title

Research Methods

Course Number

ETM 565/665


New products -- Research -- Methodology, New products -- Planning, Thermistors -- Technological innovations, Stoves -- Technological innovations


Nearly one billion people of the world’s population lack access to safe drinking water.[1] This has caused severe health problems as well as political and economic problems for many countries. Climate change has made it more difficult to access safe drinking water and is a result of black carbon (BC) and CO2 emissions. [2] The source of these emissions come from a variety of sources; among which are cooking with bio fuels and fossil fuels. Because of the negative effects of cooking, appropriate technologies have been implemented to reduce particulate emissions. However, monitoring of their utilization and effectiveness has not been properly accounted for leading to frequent failures.[3]

The Sustainable Water, Energy and Environmental Technologies Laboratory (SWEETLab), at Portland State University (PSU), is developing a method of fixing this problem. The SWEETLab develops and implements technologies for the support of life in remote environments. A key thread of the SWEETLab’s research focuses on improving accountability and methodologies for international development through improved data collection.

The goal of the SWEETLab is to proving the sustainability of efficient cookstoves by implementing an in-situ remote monitoring system,( called SWEETSense) a method of which has not been attempted yet until now.[2]

Remote Monitoring can provide solutions to many of the issues around sustainability of water treatment, energy and infrastructure intervention in developing communities such as unrealizable survey data and relying on spot checks to assess performance. [2]

The SWEETSense is designed to have a low power profile while maintaining high-resolution data logging capabilities. One valuable part of the SWEETSense is temperature sensors, thermistors. The thermistors trigger the SWEETSense to turn on whenever a cookstove is being used. The purpose of having a temperature sensor is to help minimize power consumption and allows high resolution logging of usage event while running off of compact batteries for a targeted minimum of six months.[2] When the SWEETSense is triggered on, CO and CO2 sensors will trigger, recording data as the user is using the efficient cookstove.

The overall goal of the SWEETLab is to find an appropriate method of calibrating the SWEETSense. As the SWEETLab progresses forward in mass production, the SWEETSense will require a faster calibration process. For the focus of this project, the temperature sensors of the SWEETSense will be studied.

The project goal is to figure out the best process of calibrating the temperature sensors using a calibration bath while maintaining a 3-degree error goal, set at four calibrated temperature ranges; 21.3 °C (ambient), 35°C, 60°C and 80 °C. Over the course of five weeks, variations of calibration tests were performed on the sensors using the calibration water bath however the problem found was that there was a large amount of time spent performing the calibration tests while little progress was made in calibrating the sensors.


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