According to an aspect, there is provided a training device for use in an inhaler, the training device comprising a body that is configured to be received at a first position in a housing of an inhaler, wherein the body comprises an interface arranged to connect to a canister interface in the housing of the inhaler; an electrical circuit configured to perform one or more functions; and a circuit triggering mechanism that comprises a switch for enabling the electrical circuit to perform the one or more functions when the switch is closed, wherein the circuit triggering mechanism is configured such that the switch is closed when the body is pressed from the first position towards the canister interface and into a second position in the housing of the inhaler.