Firstly, apologies for a rather rookie question, I haven't been doing electronics for a decade or two. Now I got a Wemos D1 mini board, DFPlayer mini mp3 player and a SSD1306 OLED display (128x32) with I2C. I have managed to get either the DFPlayer or the OLED display to work with the Wemos board, but not both at the same time.
The problem is that I can't figure out how to connect them at the same time as they both seem to be working only when I connect them to pins D5 and D6 of the Wemos board (with DFPlayer: D5 -> RX, D6 -> TX, and with SSD1306: D5 -> SDA, D6 -> SCL). As far as I know, the DFPlayer doesn't support I2C so I can't just go and hook them together, can I? I tried the other pins as well but couldn't get anything out from either of the devices.
Pinout of the Wemos is: LOLIN D1 mini — WEMOS documentation
Just I have hard time understanding why can't I use the other pins than D5 and D6.
Can anyone give me any directions here?