Senior Project Blog Post #8: Volume Control

This week I mostly worked on the circuit board for volume control since that is the last main component I need to get this project working. The circuit works by providing 24 volts to the solenoid when a note is turned on initially, and then stepping the voltage down to 12 volts after a certain period of time. This period of time is varied by the volume data supplied from the MIDI Decoder. this works using a latch and a binary counter such that when a note’s state is changed, the latch is set (1 = note on, 0 = note off) and the velocity information is stored in the counter. The counter is then set to count down, and keeps the voltage at 24 volts, setting it to 12 volts when the counter reaches zero. This way higher velocity notes will have the solenoid have more power (24 volts) for longer, in theory producing a louder sound. I wasn’t able to get as much progress done on the circuit board design as I would have liked to this week, but I hope to have a finished board (and possibly notes playing with varied volume!) next week.