When i paste this on google - https://cloud.boltiot.com/remote/MY API KEY/analogRead?pin=AO&deviceName=BOLTXXXX
I get the follwing result - {“value”: “180”, “success”: 1}
But that is not the sensor reading from my ldr sensor. I read in this documentation that it is the voltage on theat pin. Instead, I want to see the light intensity. How can i do that?
To obtain the light intensity from your LDR (Light Dependent Resistor) sensor using the Bolt Cloud API, you need to convert the voltage reading to the corresponding light intensity value. The voltage reading alone does not directly provide the light intensity.
Here’s a general approach to converting the voltage reading to light intensity:
Gather some reference data: Measure the voltage output of your LDR sensor under different light intensity conditions using a multimeter or other reliable measurement device. Note down the voltage readings and their corresponding light intensity values. For example:
| Voltage (V) | Light Intensity (%) |
|---|---|
| 0.5 | 10 |
| 1.0 | 20 |
| 1.5 | 30 |
| … | … |
Create a calibration curve: Plot the collected data points on a graph with voltage on the x-axis and light intensity on the y-axis. Fit a curve (e.g., linear, polynomial, or exponential) to the data points to establish a relationship between voltage and light intensity.
Use the calibration curve to convert voltage to light intensity: Once you have the calibration curve, you can use it to convert the voltage reading obtained from the Bolt Cloud API to the corresponding light intensity. To do this, you’ll need to apply the appropriate mathematical equation or algorithm derived from the calibration curve.
By performing these steps, you’ll be able to obtain the light intensity value instead of just the voltage reading from your LDR sensor.
Note: The specific calibration process may vary depending on the characteristics of your LDR sensor and the range of light intensity values you want to measure. The calibration curve and equation will be unique to your specific sensor and setup.
It’s also worth noting that some LDR sensors may have built-in circuitry to directly provide light intensity readings rather than voltage. In such cases, you can follow the manufacturer’s documentation to obtain the light intensity values without the need for calibration.
Hi, @jindaldhruva
If you are receiving a value of “180” when making the analogRead request to your Bolt IoT device, it indicates the voltage reading on the specified pin (A0 in this case). To convert this voltage reading into a light intensity value, you need to calibrate your LDR (Light Dependent Resistor) sensor.
Here’s a general approach to calibrate the LDR sensor and obtain light intensity readings:
Measure the voltage range: Place the LDR sensor in different lighting conditions to cover a range of light intensities. Use a multimeter to measure the corresponding voltage values at each lighting condition. Note down the voltage readings and their corresponding light intensity levels (you can use a lux meter or estimate the light intensity qualitatively).
Create a mapping function: Once you have a set of voltage readings and their corresponding light intensity values, create a mapping function to convert the voltage readings to light intensity readings. You can use techniques like linear interpolation, curve fitting, or lookup tables to map the voltage values to light intensity values.
Update your code: Modify your code to include the mapping function that converts the voltage readings to light intensity readings. Instead of using the raw voltage value, use the mapped light intensity value in your application or further calculations.
By calibrating your LDR sensor and mapping the voltage readings to light intensity values, you can obtain more meaningful and accurate results for your light intensity measurements.
Note: The specific calibration process may vary depending on your LDR sensor and the range of light intensities you want to measure. It’s recommended to consult the datasheet or specifications provided by the sensor manufacturer for calibration guidelines specific to your sensor model.
Reference:
To convert the voltage reading from your LDR (Light Dependent Resistor) sensor into light intensity, you need to understand the characteristics and behavior of your specific LDR sensor. LDR sensors typically have an inverse relationship between resistance and light intensity.
Here are the steps you can follow to calculate light intensity from the analog voltage reading obtained from your LDR sensor:
The formula for linear interpolation is as follows:
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Intensity = Imin + ((Voltage - Vmin) * (Imax - Imin)) / (Vmax - Vmin)
You need to replace the variables in the formula with the specific values from your LDR sensor.
Here’s an example Python code snippet that demonstrates how you can calculate light intensity using the linear interpolation formula:
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Vmin = 0.0 # Minimum voltage value from your LDR sensor
Vmax = 3.3 # Maximum voltage value from your LDR sensor
Imin = 0.0 # Minimum light intensity corresponding to Vmin
Imax = 100.0 # Maximum light intensity corresponding to Vmax
voltage = 2.5 # The voltage reading obtained from your LDR sensor
intensity = Imin + ((voltage - Vmin) * (Imax - Imin)) / (Vmax - Vmin)
print("Light intensity:", intensity)
Make sure to replace the Vmin, Vmax, Imin, and Imax values with the specific values for your LDR sensor. Also, replace the voltage variable with the voltage reading you obtained from your API call.
By using this formula and customizing it based on your LDR sensor’s characteristics, you can convert the voltage reading to an appropriate light intensity value.