Unreliable readings for Light intensity monitoring project

In my first project, the table is showing the same value again and again(1.02thousand) for the connection with 10k resistor, and with 330 resistor, it shows an integral value less than 100 as soon as it gets power but after some time it again shows 1.02 thousand.

Please go through these steps @dhruvakrishnamaraju

  1. Look at the time of update. It may be that you are looking at old value, and not the new once.
  2. Check the connections of the resistor to a0 pin and GND.
  3. Try covering the LDR with your finger, and clicking on push data while your finger is on the LDR.
  4. Some students have received an LDR with internal resistance which is different from the standard. Try using the following combinations in the given sequence
  • 3.3v - LDR - a0 Pin - 10k - gnd

  • 3.3v - LDR - a0 Pin - 330 - gnd.

Hope this works for you. Do let me know if you need further help.

Yeah I have already checked all the above steps. But still same value is printed. Could it be because of heating up of the chip.

Please try to change the light intensity and then you will notice the difference. Like Setup your device in your balcony at 3 am and record till 8 pm . You will see significant data because as the sun sets , it will also change light intensity . You can also move your device in different rooms with different lightning conditions . 1.02 usually occurs for LED in our rooms .


Please try using the 330 ohm resistor between a0 pin and GND pin, and connecting the LDR between a0 and 5v pin.

The default internal resistance of the LDR tends to be pretty difficult to predict. Since you are getting a value in the range of 100 for 330 resistor with 3.3v supply, with a 5v supply, the values will reach 150 levels, which is consistant with indoor room lighting.

To get higher values try to flash a tourch at the LDR.

Did you check with 330 ohm resistor? @dhruvakrishnamaraju

Thank you guys for all your help, I’ve got it.

take a gap while uploading the code configuration