Device development
/Used Arduino Mega ADK as microcontroller.
Device phase 1: Getting the idea
The sensors were simply put on the breadboard. There were 9 sensors connected; lux, DHT, 2 Accelerometer, Barometric pressure, Oxygen, Air contaminants, Hydrogen, and Propane Ethanol. The focus was more on to see which sensors were sensitive to changes. It was also to see what additional sensors were needed to get useful measurements. The setup was relatively simple, so it didn’t have an enclosure.
Device phase 2: Field testing
Breadboard seemed to be fuller with added sensors. There were 13 sensors connected; lux, DHT, Barometric pressure, Sonar, Accelerometer, Propane Ethanol, SD card reader, Ozone, Alcohol gas, Carbon Monoxide, Hazardous gas, Oxygen, Dust. Air contaminants and Hydrogen sensors were taken out because the other sensors were able to detect air contaminants and Hydrogen as well. There was no need for repetition. In addition to newly added gas sensors, second phase device had hardware that allowed field testing. SD card reader, a switch, and an LED light bulb. SD card reader saved the data on the SD card so there was no need to bring laptops. The switch turned on and off the setup so selective testing on specific location was possible. LED light bulb was used for keeping track of the order of measurements. Setup was put inside a box to be more secure.
Device phase 3: sturdy and less intrusive
Setup became even more complex and to start the actual testing, there was a need for a better enclosure. The enclosure needed to protect the sensors yet allow ventilation for air sensors. Setup also needed to be less conspicuous. With the wires hanging out of the boxes, people might think the setup is a bomb. Another feature of phase 3 of the device was that it integrated an LCD screen. The screen kept track of time, order, and initiation so the setup no longer needed a huge button or the bright red LED light.