I'm not good at electronic engineering. But i have to make led transmitter(for visible light communication). Now, i use arduino and mosfet like this picture. I should choose proper power supply(external power) and COB(chip on board) led. I will buy 24v power supply(output 23v, 52.8w, 2.2A | input 86~264VAC). Then, what should i check when choosing cob led? And, Can you give me some proper led list for me?
For successful visible-light communication, the data-link needs to handle/ignore the sunlight and the 120Hz of lightbulbs and the 80KHz of desk lighting. To ignore the sunlight (a DC source of overload), you need negative feedback used in a phototransistor (3 leads, including the base); wire 2 resistors in series, connected from collector to base. Use 100K ohms to start. Place 1uF cap from midpoint to Ground. This 2R/1C network allows DC nulling of the sunlight, but shuts down the feedback at higher frequencies, so your modulated energy gets preserved. Use a 1Kohm from collector to +5volts. Again, use a 3-lead phototransistor.
This makes a very sensitive "receiver" and you may not need much power from the LEDs.