BakeBit - Light Sensor

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Light Sensor
  • The BakeBit - Light Sensor is a photoresistor module. The resistance of a photoresistor decreases with increasing incident light intensity.
  • If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance.

Hardware Spec

  • Standard 2.0mm pitch 4-Pin BakeBit Interface
  • PCB dimension(mm): 20 x 24
  • Analog Outpu

BakeBit - Light Sensor

  • Pin Description:
Pin Description
GND Ground
5V 5V Supply Voltage
NC Ground
SIG Signal

Code Sample: Smart Lighting

By running this code sample your system adjusts the LEDs on the LED module(LED Bar) according to surrounding lightness. When the surrounding environment becomes darker the LEDs will be brighter. When the surrounding becomes bright enough the LEDs will be completely off. A BakeBit - LED Bar module is needed in this test case.

Hardware Setup

Connect the BakeBit - LED Bar module to the NanoHat Hub's D3 and the BakeBit - Light Sensor module to the NanoHat Hub's A0:

Smart Lighting-1.jpg Smart Lighting-2.jpg

Source Code

import time
import bakebit
# Connect the BakeBit Light Sensor to analog port A0
light_sensor = 0
# Connect the BakeBit LED Bar to digital port D3
ledbar = 3
lowThreshold = 500
highTreshold = 600
bakebit.bakeBitLedBar_Init(ledbar, 0, 5)
old_color = 0
while True:
        light_count = 0
        # Get sensor value
        sensor_value = bakebit.analogRead(light_sensor)
        if sensor_value > highTreshold:
            light_count =  (sensor_value-highTreshold)/f+1
            # turn on ledbar
            color16bit = bakebit.Green
            if light_count > 1:
                color16bit = color16bit | (bakebit.Green << 3)
            if light_count > 2:
                color16bit = color16bit | (bakebit.Green << 6)
            if light_count > 3:
                color16bit = color16bit | (bakebit.Green << 9)
            if light_count > 4:
                color16bit = 0
                color16bit = color16bit | bakebit.Blue
                color16bit = color16bit | (bakebit.Blue << 3)
                color16bit = color16bit | (bakebit.Blue << 6)
                color16bit = color16bit | (bakebit.Blue << 9)
                color16bit = color16bit | (bakebit.Blue << 12)
            if color16bit != old_color:
                old_color = color16bit
                lowBits = color16bit & 255
                highBits = (color16bit & (255 << 8)) >> 8
                bakebit.bakeBitLedBar_Show(ledbar, highBits, lowBits)
        elif sensor_value < lowThreshold:
            # turn off ledbar
            bakebit.bakeBitLedBar_Show(ledbar, 0, 0)
        print("sensor_value = %d light_count =%d" %(sensor_value,  light_count))
    except KeyboardInterrupt:
    except IOError:
        print ("Error")


Run Code Sample

Before you run the code sample you need to follow the steps in bakebit tutorial to install the BakeBit package.
Enter the "BakeBit/Software/Python" directory and run the "" program:

cd ~/BakeBit/Software/Python
sudo python


When you cover the smart lighting’s photo sensor or make the surrounding environment brighter the LEDs will be on or off.
The LEDs on the LED Bar module will be turned on or off according to surrounding environment’s lightness. When the the surrounding environment becomes darker more LEDs will be turned on otherwise the LEDs will be off.


Update Log


  • Released English version


  • Renamed "NEO-Hub" to "NanoHat-Hub"


  • Renamed "NanoHat-Hub" to "NanoHat Hub"