Ragnar Danneskjold said,
"I believe the devices have other sensors in them to determine temperature, humidity, etc of the air you put into it to make falsifying it harder."
Then I guess you'd need a warm, wet, solder-sucker, baby snot-sucker, fireplace bellows, or tire-inflator compressor.
Or a warm, wet, 8-year-old daughter.
Terry, 230RN