A drug delivery device is provided comprising a drug-filled cartridge or means for receiving a drug-filled cartridge, and drug expelling means comprising expelling means for expelling an amount of drug from the cartridge, and an indicator member arranged to move corresponding to an action performed on or by the drug delivery device. The device further comprises an energy source, wireless communication means, sensor means adapted to detect movement of the indicator member, and a processor adapted to (i) receive input from the drug delivery device indicative of indicator member movement and (ii) control the communication means to transmit a data signal comprising coded information derived from received input from the sensor means, wherein the wireless communication means is in the form of a sound transducer.
