Pen-type drug injection device and optical dose value decoding system with additional sensor to distinguish between dose dialling and dose delivery mode
An optical decoding system comprising: a first optical sensor configured to be directed at a first rotatable component of a drug delivery device； a second optical sensor configured to be directed at a second rotatable component of a drug delivery device； and a processor configured to: receive signals from the first optical sensor, wherein the signals from the first optical sensor represent encoded dosage values present on the first rotatable component； receive signals from the second optical sensor, wherein the signals from the second optical sensor represent whether the second rotatable component is rotating or not； and to determine from the received signals whether the drug delivery device is in a drug dose dialing mode or a drug dose delivery mode.
