Pharmaceutical companies and pharmacies are making a switch from polypropene  (PP) to polyethylene terephthalate (PETE) bottles for prescription fulfilment. The amber coloured PETE bottles are cost effective and easy to recycle, however the plastic’s clear (almost semi-transparent) appearance poses a challenge to standard red LED sensors that are used in pharmaceutical plants.
Sensors with red LED’s that have been used in the past essentially see through the PETE bottles, causing problems such as missed detection, double counting and mislabelling. With hundreds of red LED sensors needing to be replaced, Banner Engineering was approached to come up with a solution.
After many hours of testing it was found that the best solution was to replace the red LED with a blue LED light source. Banner modified the retroreflective version of the standard QS18 sensor to reliably detect the amber PETE bottles with better contrast. The custom QS18’s blue LED is effective up to 300mm away from its reflector, while the potentiometer is convenient for sensitivity adjustment, making the sensor a good solution for both long and short range applications. And because the QS18 is a common form factor, users are able to replace their existing sensors while keeping costs and wiring down to a minimum.
With a simple modification of the LED wavelength, Banner tailor-made a solution that not only solved the application, but provided cost benefits and improved quality of the product.