Trigger MIDI Converter Using eDrum

Overview

The project illustrates the construction of an electronic Trigger to MIDI Converter module based on PIC microcontroller in order to create the eDrum.

Details

A PIC16F877 RISC microcontroller is used to design the eDrum which contains some operational amplifiers, two 16x2 LCD with backlight, and runs at 20MHz. The device also consists of one serial RS232 out, one MIDI out, 4 control buttons, 22 input gain potentiometers, 2 digital inputs, and 22 analog inputs. The use of carefully designed firmware written in assembly language as well as the PIC microcontroller achieves an easy expandable and modular design with cheap electronic components but with results maintained at the professional levels.

For the users of PC without MIDI input, the circuit will include MAX232 and DB9 connector. For analog and digital part of the circuit, there are two separate voltage regulators in the power supply unit. A sufficient wall transformer is used with an output voltage from 12 to 15V and some 500mA. The values of the current limiting resistors can be adjusted for optimal brightness if the LCD has backlight. To avoid ground loops, the analog and digital ground must be in a single point.