Light Intensity Monitoring System

The A0 point is the analog point and it takes in the value of voltage between 0 to 1.The taken value say 0.576V is converted to a binary number of 10 bits,by the in built ADC converter.So each value read by A0 pin is given by 10 bit binary number whose decimal equivalent ranges from 0 to 2 power 10-1(this decimal equiv. is shown in the output table).
Now in our case at bright light LDR,resistance lowers down and it gives less drop so A0 pin gets high value.For dark case resistance increases,and gets good drop so A0 pin gets low value.
Thank You!!

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Instead of using Chart,
Can we use Graph so that it would be easy to understand?

yes in future classes you will learn that too.

No, the data does not get lost . The previous data are stored and you can continue to enter data even you do the same next day. Just recheck and ensure internet connection and wait for a while to see your previous data values.

Actually when we have connected all the components correctly we will have the 2 led lights glowing on our bolt module but instead there is only one glowing and that is too the wifi that means you have connected to wifi but there is some problem regarding your connection with bolt cloud or simply your bolt device is having some problem to connect with your the cloud.So my opinion is that please try it once again by changing the usb cable that you have previously used since there is a problem with the connection with the bolt cloud. Thankyou.

Can we get the graphical data instead of the chart ??

Instead of connecting one lead of your resistor to 3.3 V pin connect it to 10 K pin and try. It might work for you. Also make sure you turn of the power supply while making any connections to ensure that the hardware is undamaged.

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Right now, only chart representation is available on Bolt Cloud. However, you can surely export the data and visualize it through graphs using Excel Sheet


You can visualise the data using graph. Please visit the documentations here

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i have created my first project with bolt which is light intensity monitoring system but the value is constantly zero. I have done all the troubleshooting given in the tutorial but still the value is not changing. now i have transferred the circuit to the breadboard but still the value is zero and not changing up. plzzz help me.

@lakshyarao22 Can you share the connections that you have made? Most probably,

  1. You have made an incorrect hardware connection.
  2. The hardware config on the cloud is incorrect.
  3. The code to visualize the data is incorrect.

What is the date shown on the data point in your graph?

@robot.bkp I had the same problem, my problem was I saved the product very quickly and exited the editing page. I suggest you to the following:

  1. un-link the product from the device.
  2. delete your whole product completely.
  3. create a new product and follow the video tutorials thoroughly.
  4. link the project again to the controller.

This procedure worked for me and I believe it will also work for you. Peace :v:

I have again deployed the code the date it is showing is 17 Aug 2019, The date is correct.
i have checked all the mentioned problems and double checked it from the video. I can surely say that these are not the problems. the problem is something else.

my code is

where ldr is variable configured to a0

and also my picture is not uploading to the fourm, it is showing access denied

@lakshyarao22 Can you share your browser details and the product details to

Hi @tantreshwarjha14 !
I am unable to understand the values obtained by the light monitoring system and what this values signify?
You have explained it but can you please elaborate it. Is there any upper and lower limits of these values?

Hi @gauravchhabra.pec.Consider a circuit in which ldr and a resistor in series

Ldr is connected to vcc and then a resistor…
Now when light falls ldr resistance lowers down…hence you can say ldr behaves as short circuit…so vcc appears as output…now this goes to A0 pin which converts it to 10 bit binary number…as it is maximum value…the binary number is 1111111111…so instead of displaying 10 ones it displays decimal equivalent 2^10=1024
Now when it is dark ldr behaves as open circuit…in other words current is 0.So no drop is in resistor and we get 0V at output…this goes to A0 pin where it is converted to 0000000000…ie it will display 0V
But since ideal ldr do not exist you will not get exactly Vcc at output in light case or 0V in dark case…approximate values come…
Note:A0 pin converts the analog value say 0.573V to 10 bit binary number…in display it gives decimal equivalent of same…

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