AirWick Freshmatic Teardown – Bypass Protection Method

 

You probably have a few of these AirWick Freshmatic room fragrance sprayers in your house. One thing I noticed on the packaging was it could only be used with AirWick refills. I was curious how they could tell the difference between Airwick and generic refill canisters. Turns out there is a Vishay TCNT2000 Reflective Optical Sensor that is at the heart of their protection scheme. It simply looks for the black bars that are printed on the neck of the spray can. As the can is sprayed the sensor is watched to ensure the black bars move past the sensor when expected. If the bars aren’t present the system immediately flashes the red light indicating. You can see in the video below that it continues to monitor the sensor for about a second after the motor is turned off to ensure the plunger eventually moves back to the correct position. The build quality is amazing for a small throw away device. When you consider the device is basically free when you purchase a set of spray cans with the sprayer it reminds me of inkjet printers which were often almost free in the hopes that you will spend hundreds on replacement inkjet cartridges. 

If you end up with a damaged neck label which prevents a can from spraying or if you have some cans that don’t have the the barcode present you can download and print the barcode here, it is basically some 2mm black and white stripes.