Byamber
Use Raspberry Pi to get light strength data with photoresistor
Objective
In this project, we will use Raspberry Pi to get light strength data with photoresistor . As raspberry pi can not handle analog input, we need an A/D adapter to convert analog voltage into digital signal. You can select either MCP3008 ,MCP3204 or MCP3208 module as A/D adapter. In our experiment, we selected MCP3208.
Parts and Devices
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Devices
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qty
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Raspberry pi2/3
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1
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8GB MicroSD memory card preinstalled Raspbian OS.
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1
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GPIO breakout kit(optional)
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1
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A/D adapter
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1
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photoresistor
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1
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10K ohm resistor
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1
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breadboard
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1
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jumper wires
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some
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Circuit Connection Graph（MCP3208 or MCP3008）：
MCP3208 and MCP3208 are very similar, the datasheet of these two modules are sa following:
MCP3008_datasheet.pdf
Circuit Connection Graph（MCP3204）：
Install software:
1. connect your Pi to internet and then install GIT with following terminal command:
sudo apt-get install git-core
If there is any error during git installation, run following commands first, then do GIT installation again.
sudo apt-get update
sudo apt-get upgrade
2. download wiringPi library installation package with GIT
git clone git://git.drogon.net/wiringPi
If you need updated wiringPi, run following commands:
cd wiringPi
git pull origin
3. Build wiringPi library
cd wiringPi
./build
4. Download sample code by running following command:
wget –no-check-certificate http://osoyoo.com/wp-content/uploads/samplecode/raspi_photoresistor.c
5. compile sample code with following command:
gcc -Wall -o app raspi_photoresistor.c -lwiringPi
6.run the code:
sudo ./app
After running the sample code, your pi terminal will show light value as following:
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