I am trying to make a visible light communication (something like LiFi) on my RPi4. I already have TX part completed, but I have a few problems with RX part. Firstly I was trying to use phototransistor to read the light bits from the TX LED. Unfortunately, this phototransistor has fall and rise time around 4,5 ms which is too slow for speed data transmit. I want to be able to send and receive data around 30 to 50 kHz frequency. That means I need something which has photodiode with fall and rise time around 20 to 33 us.
- I have a two options right now. First is that I will use BPW21 photodiode combined with AD converter MCP3008.
- Second option is to use an Adafruit TSL2591, which can be easier to use and wire.
I am not sure, if Adafruit can be as fast as photodiode with ADC. So my question is: Which option can you recommend to me please? I am new in this field and I will be thankful for any type of recommendation.