After my maths teacher prohibited us from using phones in class at all, I bought a DFPlayer Mini to build into my calculator so I could still listen to music. I just soldered to the pads and created button combinations to control the player, it turned out that this didn't work very well so I shelved the entire project.
After I discovered the ATtiny series of microcontrollers I wanted to try again. (I bought an ATTiny85 and couldn't find an other use for it.) I connected the ATtiny to the TI-84's link port and by using Send() commands in a simple TI-Basic program you can now control the DFPlayer, the ATtiny acting as a translator between the calculator and the player. It takes integer values sent from the calculator using the ArTICL library and maps those to command for the DFPlayer which are then sent over to the player using SoftwareSerial.
The player does have a separate power switch, I tried to use the USB-OTG power the calculator provides, however, that requires the calculator to be on when listening to music all the time which is not great for battery life.
- DFPlayer Mini
- TI-84 Plus
- 3.5mm Jack
- Toggle Switch