This is what I added
- extra male headers next to all I/O and power pins
- added serial/I2C/IIC adapter board LCD1602 to be able to control the LCD+backlight with only 2 I/O-pins + LCD pin reassignment via jumpers (control + power + backlight)
- DS1307 real time clock + 24C32 EEPROM-pcb
- MCP23017 chip on free soldering pads under LCD display -> 16 extra I/O-ports!
- buzzer on free soldering pads under LCD display
- 6 extra Grove compatible IIC-connections (4 female + 2 male; next to buttons) for easy connection with the popular Grove brick modules
- extra connection for external LCD backlight and buzzer control
This picture shows you the changes on the upper pcb side |