I built the novadreamer clone all by myself, so it’s quite different from the kvasar. It’s easy to replace the sensor with a photodiode on the kvasar but the program would have to be remade and since I don’t know the language he’s using I don’t know how easy/hard it’s to change 
You
I used a language called picbasic and there it’s simple to read the photodiode. There’s even a command for doing it 
But since the resistance of the diode was way too high I also had to put a resistor paralell with it to be able to read it.
Here’s a topic about building the kvasar [REM Detecting LED Goggle Device Nova Dreamer Wanna Be Thing)