Resonant Cavity Light-Emitting (RCLED) diode, (whose price exceeds several thousand dollars) or diffusely scattered laser LED diodes would be ideal solution if we can ignore price, cost of assemby and health hazards.
With the aim to focused on the development of sustainable solutions using the widely available technology (preferably more accessible prices) that can be of applied in IoT and sensor systems and whose total power consumption does not exceed 2W (maximum 5W). Taking into account the above guidelines after the initial consideration and experiments we decide not to use ≥1W Hi-Power LED, since their nominal supply current while running is ≈350mA, and pulse at the beginning of the emission cycle goes through 500-550mA. As a substitute in the solution was applied Ultra-Bright / Superbright (UB) 5mm LEDs designed to work in outdoor daylight condition in signaling devices and large LED panels. UB-LEDs are on the market in average 3 to 5 times cheaper than 1W Hi-Power LED, provide a focused beam of the semi-angle φ1/2 of 8-30° with the intensity of light emission from 8000 to 37000mcd (mili candela) at Forward current If = 20-35mA (with 75-90mW we can find even > 57cd UB-LEDs ).