Introduction

My name is Ryosuke Kamei and I am an IT consultant based on the idea of "gentle IT"! Currently, in my work, I am doing upstream processes focusing on requirements analysis and requirements definition, but I also write programs! As part of our friendly IT activities, we will introduce "Raspberry Pi 3" (commonly known as Raspberry Pi), which has the philosophy of "providing inexpensive PCs that can be programmed for education"! This time, we will detect the temperature! !! !! [Razpai Magazine-June 2016 Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 ⑥ Digital Temperature Sensor](https://www.amazon.co.jp/ Razpai Magazine-June 2016 Issue-Nikkei BP PC Best Mook - the Nikkei Linux-ebook / dp / B01EH2RX42 / ref = as_li_ss_tl ie = UTF8 & dpID = 61P3o6Agz + L & dpSrc = sims & preST = OU09__BG0,0,0,0_FMpng_AC_UL160_SR120,160 & psc = 1 & refRID = 31SKG5E0DGKBSF9BWNGV & linkCode = ll1 & tag = sr2smail-22 & linkId = 18fd04738627edef8d6fffd6c9b8f9c2)? I am referring to it. Finally, it's a story that seems to be a work story for my daughter (11 and 9) during the summer vacation! (I'm sorry for my personal cry)

procedure

Wiring
Preparation
Program digital_temperature_sensor.py
Run the program

1. Wiring

The wiring diagram is [Razpai Magazine-June 2016 Issue Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 ⑥ Digital Temperature Sensor](https://www.amazon.co.jp/ Razpai Magazine-June 2016 No.-Nikkei BP PC Best Mook-Nikkei Linux-ebook / dp / B01EH2RX42 / ref = as_li_ss_tl? = 18fd04738627edef8d6fffd6c9b8f9c2) As it is.

If you get an image like this, referring to the picture of the circuit Raspberry Pi 3でpythonを使い温度を検出する！回路.jpg

I also made a video

Text version

--Raspberry Pi Pin 1 (3.3V) --Digital Temperature Sensor VDD 4 --Raspberry Pi 6th pin (GND) --Digital temperature sensor GND 1 --Raspberry Pi Pin 3 (SCA) --Digital Temperature Sensor SCA 2 --Raspberry Pi Pin 5 (SCL) --Digital Temperature Sensor SCL 5

2. Preparation

Install the required library (libi2c-dev).

`libi2c-dev install`


$ sudo apt-get install libi2c-dev

Write to the configuration file.

`bash:/etc/modprobe.d/i2c.Write settings to conf`


$ sudo sh -c 'echo "options i2c_bcm2708 combined=1" >> /etc/modprobe.d/i2c.conf'

Enables I2C.

Check if I2C can be used

`Confirmed with i2cdetect (it seems to be 0 depending on the partial version of 1)`


$ sudo /usr/sbin/i2cdetect -y 1

3. Program digital_temperature_sensor.py

Program is also [Razpai Magazine-June 2016 Issue Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 ⑥ Digital Temperature Sensor](https://www.amazon.co.jp/ Razpai Magazine-June 2016 Issue- Nikkei BP PC Best Mook -? Nikkei Linux-ebook / dp / B01EH2RX42 / ref = as_li_ss_tl ie = UTF8 & dpID = 61P3o6Agz + L & dpSrc = sims & preST = OU09__BG0,0,0,0_FMpng_AC_UL160_SR120,160 & psc = 1 & refRID = 31SKG5E0DGKBSF9BWNGV & linkCode = ll1 & tag = sr2smail-22 & linkId = 18fd04738627edef8d6fffd6c9b8f9c2 ) Was used as a reference. Almost as it is.

The source is uploaded to GitHub, so please use it as you like.

`Clone with git`


$ git clone https://github.com/RyosukeKamei/raspberrypi3.git

`digital_temperature_sensor.py`


#Library to control GPIO
import wiringpi
#Timer library
import time
#Call the library required to read from the I2C device
import os
import struct

#Create an instance of I2C
wiringpi.wiringPiSetup()
i2c = wiringpi.I2C()

#I2C settings
#Specify the I2C address of the device to communicate
temperture_dev = i2c.setup(0x48)

#Get 16-bit temperature data
#Others Set to register 0x03
i2c.writeReg8(temperture_dev, 0x03, 0x80)

while True:
    #Read 2 bytes of temperature sensor
    temperture_data = struct.unpack('2B', os.read(temperture_dev, 2))

    #The value is divided into 2 bytes, so combine them into one.
    temperture = ( ( temperture_data[0] << 8 ) + temperture_data[1] )

    #Convert numbers for negative values
    if ( temperture_data[0] >= 0x80 ):
        temperture = temperture - 65536

    #Calculate the temperature by dividing the acquired value by 128
    temperture = temperture / 128

    #Temperature display
    print ( "temperature" , temperture , "C" )

    #Every second
    time.sleep(1)

3. Run the program

I recorded the video of how it is moving.

`Detect temperature`


$ sudo python3 digital_temperature_sensor.py

The temperature is displayed in real time! I was surprised that the temperature was almost the same as the set temperature of the air conditioner (laughs). If you touch the sensor with your finger, the temperature will rise a little!

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