= Smorgasbord =

* Stepper motors
* IR proximity sensors
* [https://www.arduino.cc/en/Reference/Serial Serial communications] note: requires a [http://www.gearbest.com/development-boards/pp_139898.htm TTL-to-RS-232 adapter] - ask a mentor.
    * [https://www.arduino.cc/en/Tutorial/SoftwareSerialExample Software Serial] (aka bit-banging) [[Image(https://hackadaycom.files.wordpress.com/2009/09/officespace.jpg?w=270, align=right, title=wrong way to bit-bang)]]
* LEDs and speakers for input
   * Speaker as microphone [http://www.circuitstoday.com/speaker-to-microphone-converter-circuit transistor preamp]
* !OpAmps 101
* Capacitors, Inductors, and Resonance
* LCD displays
* LIDAR
* 6 or 9DOF sensors