I am recently working on a Li-Fi based communication where i used a 5v solar panel to receive the binary transmitted by the laser from the other arduino but i want to use a ldr to do the same job.... any guidance regarding this ?
LDR is slow and may not be right for you. You should also compare the wavelength of the laser and the sensitivity of the LDR for which wavelength is the highest. You might be better off using a photo diode instead of an LDR.
sorry i dont have a photo diode available immediately i can only use an ldr and some basic ics
http://lednique.com/opto-isolators-2/light-dependent-resistor-ldr/ - Response time of 2 – 50 ms. (Much slower than photo-transistors.)
Do you have LEDs? It is possible to use ordinary LEDs as light detectors and since you will be using it for data it makes the task a bit easier. The sensitivity to a certain wavelength in LEDs depends on what wavelength it emits when it works as a source. Google it for more detailed info if you want. You can try different color LEDs to see how they will work with your laser and thus tentatively decide which LEDs to use.
Sorry the circuit is irresponsive
Try changing the LED. I've seen them all ways (flat neg, flat pos, die pos, die neg). "Nowadays", the flat on the circumference is (almost always) the cathode.
Also, the output will not be spectacular. It needs more gain (another amplifier, X10, X50 ?? on its output).
what ic are you reffering to ? i am having on 555 amd lm358 only
It may not be needed for digital communication. I have tried LEDs as a photodiode directly connected to a microcontroller pin and a GND. The program sets the pin as a digital output and with high potential for a very short time so that the PN junction of the diode is connected back and charged as a capacitor. After that, the pin becomes a digital input and the program monitors how long it will take to read logic 0. The PN junction of the LED diode discharges at a different rate depending on the illumination.
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