===== Подключение датчика DHT22 к banana Pi =====


VCC (+) -> контакт 3,3 вольта (1-я ножка) на CON3\\
GND (-) -> контакт GND (6-я ножка) на CON3\\
Data (S) -> контакт GPIO4 (7-я ножка) на CON3\\

{{:bananapi:dht22:dht22-pinout.png?200|}}{{:bananapi:dht22:dht22_circuitry_wiring.jpg?200|}}

Устанавливаю WiringBP

  git clone https://github.com/LeMaker/WiringBP.git -b bananapi
  cd WiringBP
  chmod +x ./build
  ./build

  git clone https://github.com/BPI-SINOVOIP/BPI-WiringPi.git -b BPI_M1_M1Plus
  cd BPI-WiringPi
  chmod +x ./build
  ./build  

С первого раза не собралось. Т.к. я собирал из под roota в файле build удалил все sudo.
В конце установки вижу
  All Done.
  
  NOTE: This is wiringBPi v1, and if you need to use the lcd, Piface,
    Gertboard, MaxDetext, etc. routines then you must change your
    compile scripts to add -lwiringPiDev
  
  ./build  6,60s user 1,00s system 41% cpu 18,390 total

Проверяю.

  gpio readall
  +----------+-Rev3-+------+--------+------+-------+
  | wiringPi | GPIO | Phys | Name   | Mode | Value |
  +----------+------+------+--------+------+-------+
  |      0   |  17  |  11  | GPIO 0 | ALT4 | Low   |
  |      1   |  18  |  12  | GPIO 1 | IN   | Low   |
  |      2   |  27  |  13  | GPIO 2 | ALT4 | Low   |
  |      3   |  22  |  15  | GPIO 3 | ALT4 | Low   |
  |      4   |  23  |  16  | GPIO 4 | IN   | Low   |
  |      5   |  24  |  18  | GPIO 5 | IN   | Low   |
  |      6   |  25  |  22  | GPIO 6 | ALT4 | Low   |
  |      7   |   4  |   7  | GPIO 7 | IN   | Low   |
  |      8   |   2  |   3  | SDA    | ALT5 | Low   |
  |      9   |   3  |   5  | SCL    | ALT5 | Low   |
  |     10   |   8  |  24  | CE0    | IN   | Low   |
  |     11   |   7  |  26  | CE1    | IN   | Low   |
  |     12   |  10  |  19  | MOSI   | IN   | Low   |
  |     13   |   9  |  21  | MISO   | IN   | Low   |
  |     14   |  11  |  23  | SCLK   | IN   | Low   |
  |     15   |  14  |   8  | TxD    | ALT0 | Low   |
  |     16   |  15  |  10  | RxD    | ALT0 | Low   |
  |     17   |  28  |   3  | GPIO 8 | IN   | Low   |
  |     18   |  29  |   4  | GPIO 9 | ALT4 | Low   |
  |     19   |  30  |   5  | GPIO10 | IN   | Low   |
  |     20   |  31  |   6  | GPIO11 | ALT4 | Low   |
  +----------+------+------+--------+------+-------+

Устанавливаю программу для работы с датчиком DHT22
  git clone https://github.com/seblucas/lol_dht22.git
  cd lol_dht22
  ./configure
  make

Проверяю:

  ./loldht
  usage: ./loldht <pin>
  description: pin is the wiringPi pin number
  using 7 (GPIO 4)
  Raspberry Pi wiringPi DHT22 reader
  www.lolware.net
  Humidity = 39.80 % Temperature = 32.00 *C

Создаю ссылку на исполняемый файл.
  root@bananapi /usr/local/bin # ln -s /usr/local/src/lol_dht22/loldht loldht
  loldht
  usage: loldht <pin>
  description: pin is the wiringPi pin number
  using 7 (GPIO 4)
  Raspberry Pi wiringPi DHT22 reader
  www.lolware.net
  Humidity = 42.40 % Temperature = 26.20 *C

Для удобства мониторинга и хранения данных использую rrdtool.
Создаю базу данных с двумя источниками данных therm и hum.

  root@bananapi /var/db/rrdtool # rrdtool create dht22_01.rrd --start N --step 300 \
  DS:therm:GAUGE:600:U:U \
  DS:hum:GAUGE:600:U:U \
  RRA:AVERAGE:0.5:1:288 \
  RRA:AVERAGE:0.5:6:336 \
  RRA:AVERAGE:0.5:12:744 \
  RRA:AVERAGE:0.5:144:730

Написал скрипт для добавления данных в базу данных.
  cat ht22_rrd.sh
  #!/bin/sh
  
  TEMP=`loldht | grep Humidity`
  therm=`echo $TEMP | awk '{print $7}'`
  hum=`echo $TEMP | awk ' {print $3} '`
  
  /usr/bin/rrdtool update /var/db/rrdtool/dht22_01.rrd N:$therm:$hum
  
  echo -n ${TEMP} >/run/dht-temp
  echo -n ${therm} >/var/www/therm/current_temp.csv
  echo -n ${hum} >/var/www/therm/current_hyg.csv
  
  exit 0

Добавил в cron строку для выполнения скрипта каждые 5 минут

  */5 * * * * root /scripts/dht22_rrd.sh > /dev/null 2>&1

Ссылки:\\
http://blog.slucas.fr/blog/banana-pi-7-DHT22-temperature-hygrometrie\\
https://github.com/BPI-SINOVOIP/BPI-WiringPi\\
http://wiki.lemaker.org/WiringPi\\
https://github.com/LeMaker/WiringBP\\
https://alexbloggt.com/dht11-banana-pi-teil2/