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 brightness! It is a temperature sensor that uses an analog temperature sensor and an A / D converter! [Razpai Magazine-June 2016 Issue Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 13 Can Use Inexpensive Temperature Sensors](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_SR120,0_FMpng_AC_UL160_SR120 It is based on 18fd04738627edef8d6fffd6c9b8f9c2).

procedure

Wiring
Program temperature_sensor.py
Run the program

1. Wiring

The wiring diagram is [Razpai Magazine-June 2016 Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 13 You can use an inexpensive temperature sensor](https://www.amazon.co.jp/ Razpai Magazine-2016 June 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 sr2smail-22 & linkId = 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（ADコンバーターを利用）」を検出する！回路.jpg

I also made a video

Text version From the Raspberry Pi side

--Raspberry Pi Pin 1 (3.3V) --AD Converter 8 Vdd --Raspberry Pi 2nd pin (5V) --Analog temperature sensor left side --Raspberry Pi 19th pin (MOSI) --AD converter 5 MOSI --Raspberry Pi 21st pin (MISO) --AD converter 6 MISO --Raspberry Pi 23rd pin (SCLK) --AD converter 7 CLK --Raspberry Pi 24th pin (CE0) --AD converter 1 CS --Raspberry Pi 6th pin (GND) --AD converter 4 Vss --Raspberry Pi 6th pin (GND) --Analog temperature sensor right side

From AD converter (difference only)

--AD converter pin 2 (CH0) --Analog temperature sensor center

2. Program temperature_sensor.py

Program is also [Razpai Magazine-June 2016 Issue Special Feature 1 Akiba's Popular Parts Wiring Diagram Best 17 13 Can Use Inexpensive Temperature Sensor](https://www.amazon.co.jp/ Razpai Magazine-2016 6 Monthly 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 22 & linkId = 18fd04738627edef8d6fffd6c9b8f9c2) is referred to.

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

`Clone with git`


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

`temperature_sensor.py`


#Library to control GPIO
import wiringpi
#Timer library
import time

# MCP3002（A/Specify the channel to which the D converter) is connected
SPI_CH = 0

#MCP3002 to be read (A/Specify the analog input channel of the D converter)
READ_CH = 0

#SPI initialization
wiringpi.wiringPiSPISetup( SPI_CH, 1000000 )

while True:
    # MCP3002（A/Create data to send to D converter)
    buffer = 0x6800 | ( 0x1800 * READ_CH )
    buffer = buffer.to_bytes( 2, byteorder='big' )
    
    #Get the value of CH0 using SPI
    wiringpi.wiringPiSPIDataRW( SPI_CH, buffer )
    
    #The values are sent in 2 bytes, so combine them into one value.
    input_value = ( buffer[0] * 256 + buffer[1] ) & 0x3ff
    
    #Convert input value to voltage
    volt = input_value * 3.3 / 1023
    
    #Multiply the acquired voltage by 100 to get the temperature
    temperature = volt * 100
    
    #display
    print ("temperature: ", temperature, "Voltage: ", volt)
    
    #Detected by 1 second
    time.sleep(1)