Speaker Testing

A project log for Shower Metronome

Minimize shower day dreaming, conserve a bit of water.

mulcmumulcmu 08/24/2015 at 02:081 Comment

Tested operation of the cannibalized enclosure speaker. MCU Pin 4 configured for PWM output. Resistor divider used for one leg of the speaker for 1.65V constant reference. The other leg hooked up to the PWM signal. Worked okay connected to the MCU pin with 100 ohm resistor. Need to decide how to drive speaker via transistor and test before starting PCB layout.


mulcmu wrote 08/25/2015 at 01:30 point

Driving speaker with npn transistor wasn't much louder, connected to the 3.3v reference or the 9V battery input.

Going to see how loud the stock circuit drives the board.  Maybe try to see what the mystery 4 pin device that drove the speaker in the stock design actually does.  Maybe it will get reused too.

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