Grantee Research Project Results

Final Report: Zero Power Electrochemical Formaldehyde Sensor with Novel Catalyst for Indoor Air Quality

EPA Contract Number: EPD17031
Title: Zero Power Electrochemical Formaldehyde Sensor with Novel Catalyst for Indoor Air Quality
Investigators: Peaslee, David E
Small Business: SPEC Sensors, LLC
EPA Contact: Richards, April
Phase: I
Project Period: September 1, 2017 through February 28, 2018
Project Amount: $99,926
RFA: Small Business Innovation Research (SBIR) - Phase I (2017) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Air and Climate

Description:

SPEC Sensors has developed a low-power amperometric gas sensor fabricated using modern screen-printed electronics strategies. These sensors are small (10x10x2mm), low cost (less than $1.50 to fabricate in high volumes), and very low power, requiring only microwatts for measurements. The sensors are extremely stable, robust and in some implementations, capable of very fast response times, with a wide measurement range for selective measurement of the EPA’s "criteria" air pollutants. In addition, while collaborating with KWJ Engineering Inc., SPEC has worked to design low power and zero power wireless sensor systems capable of collecting and transmitting data. The primary aim of this research focused on developing a low cost and highly sensitive formaldehyde sensor. The secondary aim was to develop a consumer friendly sensor platform capable of working with various types of sensors.

Summary/Accomplishments (Outputs/Outcomes):

Four of the highest performing sensors were mounted to the wireless/powerless NFC sensor platforms. Of those sensors, two performed well with the maximum gain the current circuit is capable of. Further sensor development, including efforts to increase the yield will be outlined and proposed for the phase II project. Both sensors had the same electrode material, but each had a different ionic liquid electrolyte.  For SPEC’s Wireless Integrated Sensor Package (WISP), we have developed an NFC enabled sensor platform that requires no onboard battery. The benefits of this system include the potential to print the sensor directly on a flexible printed circuit board (FPCB) lowering the cost of production. Additionally, this configuration requires no battery or on board power supply, as the NFC chip uses energy harvesting to read the voltage directly from the sensor. The sensor is always on, and requires no power to generate the signal, only power to read the signal. This means there is no warmup time required. The Android application was developed to read the sensors information, and convert the sensor voltage to the concentration specific for the gas (i.e. CO or CH2O). The app also stores the data to be plotted. Further app development will include alarms, location viewing, and will suggest appropriate actions (i.e. “Leave the Area!” for high levels detected).

Conclusions:

The IL sensors that have been previously selected have been assembled into the wireless electronics. Of the four sensors, two had a response to CH2O. The other two sensors may have been damaged during the preparation process, but the devices were inspected with no obvious damage.

The differential amplifier is using the maximum gain possible with this circuit configuration. To get higher gain from the circuit a new PCB will need to be manufactured. The new board design will proposed in the next phase of the project.