Make: Sensors

Chapter 4. Smoke and Gas

BEEP BEEP BEEP! The loud noise of a fire alarm has saved many lives, waking up residents before carbon monoxide lulls them into a permanent sleep. Another gas sensor, an alcometer, has kept many drunk drivers off the road and avoided lethal consequences.

When you start yawning at work or in an otherwise interesting class, the culprit could be carbon dioxide (CO2). It’s the gas all animals (including humans) exhale. Sensors in a building’s ventilation/air conditioning system could notice an elevated CO2 level and send you some needed fresh air.

The fire department can measure if there is hydrocarbon vapor in the air to avoid explosive surprises. There is also a gas sensor inside your car engine, which measures the fuel-air ...