Texas Instrument MSP430 will be used with LaunchPad to perform the programming. There should be a few 14 pin DIP modules in the parts bin.

Allegro A3144 from the parts bin for the hall effect sensor. These were sourced from Ebay and appear to be obsolete.

I have some generic beepers in the parts bin and some speakers. Beeper would be easier to implement. PWM output from MCU to speaker might allow for better feedback with differnt frequency chirps.