LDR with Arduino - Measure Light Intensity using Photoresistor 

Many thanks!

Thank's Ms. Emily for your time to leave a comment. I wish you a good luck to all your upcoming events.

Does you know what's a GAS DISCHARGE LAMP!! And can you make your own LIGHT INTENSITY METER ??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

@@thearchetype9829 *Do you know what a gas discharge lamp is?

You are so welcome!

Does you know what's a GAS DISCHARGE LAMP!! And can you make your own LIGHT INTENSITY METER ??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

@@thearchetype9829 i will do!!

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

Glad you liked it!

Glad it was helpful!

Glad it was helpful!

Hi Maco, welcome! And good job, cheers!

Glad you liked it!

Yes, indeed. You should try connecting LDR with Arduino. It'll be a fun project. Best wishes

You are most welcome Divya

I’m not entirely sure but you could try somehow reading a 0.5 second blink as a . And a 1 second blink as a - or use your own timings, whatever makes most sense to you

Far easier to generate Morse Code. Reading it gets messy. I'd use the millis() function (Arduino milliseconds since boot) sit in a while() loop waiting for the signal to go high. Grab the millis() and sit in another while loop waiting for the signal to go low. Grab the millis() again and subtract the starting millis() to get the pulse duration. This millis() stamp also begins the space. repeating this process lets you build up an array of pulse and space times. the following rules may help you sort out the difference between pulses individual letters and words, but the timings are pretty variable, especially with human generated code, so you're going to have to be a bit clever with your math. once you think you have a bunch of letters, decoding it is just a matter of referencing a table of type byte, with each letter represented as binary digits. The length of a dot is 1 time unit. A dash is 3 time units. The space between symbols (dots and dashes) of the same letter is 1 time unit. The space between letters is 3 time units. The space between words is 7 time units.

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

Does you know what's a GAS DISCHARGE LAMP!! And can you make your own LIGHT INTENSITY METER ??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

guess this is late, but its only a number from 0 to 1023, no unit. It doesnt give you any unit, its just a value which is given based on the resistance the LDR is at the current light level (Not the resistance in ohms either).

Hi Devadatta, I will keep adding more videos around Arduino and Raspberry Pi related topics in days to come. Thanks for your nice words concerning video lessons. It means a lot. Thanks

Hi Gaurav, it is possible

@@BINARYUPDATES Hi thanks for the response. Can you guide me how this can be done I am in need of the same for school project. If you want we can discuss this on email or anywhere else suitable Thanks.

I see you say 1 kOhm in the video (it's labelled as well).

Does you know what's a GAS DISCHARGE LAMP!! And can you make your own LIGHT INTENSITY METER ??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

Hi Katianuriu, Yes it will work with smaller breadboard as well. Just setup LDR circuit with Arduino on available tie points on small breadboard. Good luck and best wishes!

He doesn't know himself :D

Usually light intensity is measured in lux Since LDR is light dependent resistor we read change in resistance through ADC counts on Analog Pin of an Microcontroller. The circuit we use in this project create voltage divider arrangement to let us measure change in voltage when light falling on sensor changes. I hope you get now. Good luck

Welcome Bro😊

The value for LDR may vary as ESP8266 runs on 3.3V and Arduino runs on 5V. The other important thig contribute to accuracy of data based on value of resistor you've used with LDR Sensor. I hope this information may help you. Wish you good luck and best wishes!

@@BINARYUPDATES thanks for the help

Yes, its possible

I think at least one of the three-pin modules with the resistor built-in actually shows a pin out diagram wired this way. As far as I can tell, either way works, just be sure you know what you're expecting.

Hi Chris, thank you very much for your suggestions. Next time when I'll write arduino code wherein LDR data will be checked for lower threshold as well. Have a beautiful day!

Hi, you can use resistor of value 10K with LDR Light dependent resistor. Its standard across all input of 5V DV devices. Just like Arduino Uno which also operate on 5V DC. I hope this may help answer your question. Good luck and best wishes!

Hi Omar, you can add other LDR to A1 Pin which is analog sensor. So we'll declare new variable to store light intensity of second LDR using analogRead(A1) function. I hope this may help. Best wishes and good luck!

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

Hi, you need only one LDR for this project and other would be a normal resistor of value around 10K to form voltage divider circuit to measure the light intensity in lux which is an result of equivalent ADC counts from microcontroller on arduino uno. Usually, the two reason this may not work, One is wrong connections and other one is power make sure your arduino boards GND and 5V pin provide enough power to functions voltage divider circuit. I hope this may help you. Wish you beautiful day. Thanks

Hi Virendra, please make sure LDR and Resistor connected properly to form voltage divider circuit. The value of lux or LDR data depends on what value of resistor you've connected across LDR while connecting to A0 pin on Arduino Uno. Best wishes and good luck!

My Pleasure Emma!

Hi Adys, to achieve more resolution you need ADC with high resolution. In Arduino, ADCs are 10-bit means the output will be between 0-1024.

Hi Reinalto, that 10K resistor connected with LDR circuit form voltage divider circuit which generate variable voltage. This variable voltage we measure using Arduino Microcontroller. And later on this voltage itself will interpret as a light intensity or lux value. I hope this help you. Good luck and best wishes!

@@BINARYUPDATES this definitely help. I was using a 2k and it's not working properly, now with the 10k resistor everything is working just fine. Again, thank you for the video and keeping the good work! You're blessed!

Yes Kate you can use 3.3V as VCC as a reference voltage with LDR Light Dependent Resistor

Hi Vamshil, the values getting on serial monitor is the equivalent of change in resistor because in the end LDR is resistor whose resistance changes as light falling on its surface changes. Usually, we need to convert this value into lux because light intensity is measured in lux. I hope this help you understand LDR's functioning. Good luck and best wishes!

Hi Pulitha, the light intensity from LDR can be measured in Lux: The "lux" which is the SI unit of illuminance, measuring luminous flux per unit area.

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

A0 on Arduino is an Analog Input Pin can be used to read any analog sesnor. As in this case we used LDR light dependent resistor

Hi Sam, please do check your connection between LDR and Arduino. Sometimes its possible because of bad connections you won't get to see data....

You need to use FreeRTOS Library in Arduino Code. And create independent task for turning LED ON/OFF. Not sure your objective because you can achieve simple LDR interface without FreeRTOS. I recommend use millis() function instead

Hi Hasnain, It seems like your Arduino Code has issue. You have to write "S" capital in Serial. I hope this may help. Good luck!

my suggestion would be using a low and high pass filter. if you want to be approximate some colored plastic might do the trick!

@@LUCABALUCA but how to.measure wavelength will it give direct value?

Technical Engineer ah to measure a wavelength scientists use light spectrometers. To my knowledge they use filters to measure at each wavelength and then look at the graph ti figure ou which wl it emits at

CAN YOU MAKE YOUR OWN LIGHT INTENSITY METER with CIRCUIT EXPLANATION??? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JTcircQha3A.html Go find out

Not sure about color code since its very old method to recognise value of resistor. I use multi meter to measure value. Usually with LDR Light Dependent Resistor you can consider using resistor with value between 1k-10k Ohm. I use 10K Ohm for optimal performance to get accurate value of LUX from LDR Sensor

No VIN pin on Arduino Uno is to give input voltage to Arduino. Not to take from arduino to supply 5V to other devices like sensors, displays, motors etc.

@@BINARYUPDATES ok

Hi Omer, thanks! I think you can consider using LDR sensor to measure light intensity of surrounding and then take two or three 6x6 dot matrix display connect them together and show light intensity which means lux value on display. This could be one simple application to show in college. Also, you change the brightness of Dot Matrix display based on value of Light Dependent Resistor. I hope this may find useful. Good luck and best wishes for your project!

@@BINARYUPDATES thank you so much for your help , can I contact you in another your email , what's up or telegram? And thank you again ❤️❤️❤️

Yes, as per video. I've shown the same. The LDR to interface with Arduino to measure light intensity in surrounding.

I believe it maybe because LDR connections will be loose on breadboard. Please confirm once and give it try once more

I've used 1K ohm but you can use any resistor value between 1K to 10K while interfacing LDR with Arduino. Good luck!

Hi Vishaka the easisest way is to use Arduino Serial Plotter in Arduino IDE under Tools menu. I hope this may help you. Wish you good day, thanks!

Hi Beatrice, LED brightness depends on specification of an LED. If in case you've same LED then maybe your Arduino is not providing enough power to LED. And i consider you've not connected any current limiting resistor before LED. Usually resistor before LED used to control the current flowing through LED which in result control brightness of an LED. I hope this may help you. Good luck, best wishes

You can use 10K Ohm resistor with LDR Light dependent resistor to form voltage divider circuit with Arduino Uno Pins. Best Wishes Team BINARYUPDATES

Hi Azri, unfortunately Raspberry Pi don't have any analog pin on board. So you need to connect external ADC converter chip to interface LDR with Raspberry Pi.

@@BINARYUPDATES okay thanks for your response. I will use Arduino. Actually my project same like this, I was planed want to use LCD 1602 to view my result. What step I need to do to to get output on LCD?

Hi, you can interface Character LCD in 4-bit mode or use OLED display with I2C protocol. This will let you show light intensity value LUX from LDR on LCD screen. I have video posted in Arduino playlist on how to interface LCD Display with Arduino. I hope, you may find that tutorial useful. Good luck and best wishes!

the yellow onboard led on the arduino is connected to pin 13 internally

Hi SRG, it forms voltage divider circuit which help you measure change in output voltage because of change in resistance across LDR. I hope this may help. Best wishes!

@@BINARYUPDATES Thank you Sir

Hi Virender, I'll soon make video to show how to interface and program Arduino Uno with WS2812 RGB LED Strip. Thanks and have a goo day

The LDR used in video lesson is very commonly used LDR. One can find in any online store these days even on amazon

The photo resistor is pretty standard, there are usually one or two included in most of the beginner kits for Arduino or elegoo. But I would double check the resistor value. The photo resistor modules I've seen, where the resistor is built on a little 3-pin board, use 10K resistors.

Its a value of ADC counts which will vary based on amount of light falling on the surface of LDR Sensor. So later we can calculate Lux or illuminance

how can we use it to calculate lux please?@@BINARYUPDATES

The LDR and Arduino Code is simple you can pause video for a moment and type. Good luck!

Then what is it?