Medical injections and related devices and methods

An autoinjector, comprising:

• a housing;
• a container disposed within the housing and configured to contain medicament;
• a plunger slidably disposed within the container;
• a plunger rod configured to push the plunger through the container to dispense the medicament when the container contains medicament;
• a mechanism configured so that a dispensing movement of the plunger rod causes the mechanism to generate a sound;
• and
• a sensor configured to detect sound generated by the mechanism.

An autoinjector comprising:

• a housing;
• a container disposed within the housing and configured to contain medicament;
• a plunger slidably disposed within the container;
• a plunger rod configured to push the plunger through the container to dispense the medicament when the container contains medicament;
• a deflectable protrusion contacting the plunger rod, wherein a dispensing movement of the plunger rod deflects the deflectable protrusion;
• and
• a sensor configured to detect one or more deflections of the deflectable protrusion as the plunger rod moves.

An autoinjector, comprising:

• a housing;
• a container disposed within the housing and configured to contain medicament;
• a plunger slidably disposed within the container;
• a plunger rod configured to push the plunger through the container to dispense the medicament when the container contains medicament;
• a mechanism configured so that a dispensing movement of the plunger rod causes the mechanism to vibrate;
• and
• a sensor configured to detect vibration generated by the mechanism.

An autoinjector comprising:

• a housing;
• a needle arranged at a distal end of the housing;
• a force sensor configured to detect that an insertion force is greater than a threshold force;
• and
• a processor configured to use the detected insertion force to determine when the insertion force is greater than a threshold insertion force, and thus determine that an insertion distance of the needle into a user is greater than a threshold insertion distance.