US Patent 8714150 Inhalation device including substance usage controls

An apparatus including a first cartridge, a sensor, and a controller. The first cartridge can include a first release device configured to release a first substance into a housing. The controller can be configured to receive data from the sensor. The controller can determine an amount of first substance released by the first cartridge based on the data and estimate a remaining amount of first substance in the first cartridge based on the determined amount of first substance.