Hello. I am using an Arduino Uno and a nrf24l01 to transmit joystick data.
When I try to read the data on the serial monitor, the data appears briefly
and then turns to question marks. Does this sound familiar to anyone?
Cheers.
A slight serial data speed mismatch could cause that, or data overrun.
Use two stop bits on transmit and allow at least one character time pause between data bursts so the receiver always gets a "clean" start bit, it's not seeing a bit in the middle of a byte as a false start.
And be sure you are not overflowing the transmit buffer at the sending end - check for space in the TX register or FIFO before loading each character.