After adding Bluetooth to my iPod I thought I would try and find away to add Bluetooth to a DS Lite. It was quite tricky because I had to find away to spoof the headphones being in and out with the turning on and off of the Bluetooth dongle. Full info and wiring diagram can be found at the blog post below.
Blog post - https://facelesstech.wordpress.com/2024/02/25/ds-lite-built-in-bluetooth/