Raspberry Pi 3のセンシング値をサーバから取得・ロギング
Jul 15, 2016 03:27 · 1700 words · 4 minute read
前回まででセンサから値を取れるようになったので、今回はそのデータを利用してロギングしたいと思います。
まずはRaspberry Pi上でCGIスクリプトを実行できるようにする準備から。
$ sudo apt-get install apache2 #Apache(Webサーバ)のインストール 自動起動設定も勝手にやってくれます
$ sudo ln -s /etc/apache2/mods-available/cgi.load /etc/apache2/mods-enabled/cgi.load #CGIの有効化1
$ sudo nano /etc/apache2/sites-available/000-default.conf #Apacheの設定変更 (CGIの有効化2)
000-default.conf :
<VirtualHost *:80>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
# redirection URLs. In the context of virtual hosts, the ServerName
# specifies what hostname must appear in the request's Host: header to
# match this virtual host. For the default virtual host (this file) this
# value is not decisive as it is used as a last resort host regardless.
# However, you must set it for any further virtual host explicitly.
ServerName hoge.fuga.piyo #コメントアウトを解除、適当なサーバ名を登録
ServerAdmin webmaster@localhost
DocumentRoot /var/www/html
# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn
LogLevel debug
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
Include conf-available/serve-cgi-bin.conf #コメントアウトを解除
</VirtualHost>
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet
$ sudo nano /etc/apache2/mods-available/mime.conf #CGIの有効化3
mime.conf :
AddHandler cgi-script .cgi .py #219行目あたり コメントアウトを解除、追記
$ sudo gpasswd -a www-data gpio #Webサーバの実行ユーザがGPIO周りを触れる用にする (ユーザ www-data のグループ gpio への追加)
$ sudo apachectl graceful #Apacheを再起動
これで準備は完了です。
Raspberry Pi用のサンプルコードがこちら (前回までに出てきたものと同じです)
get_hdc1000.py 温湿度取得用 :
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import RPi.GPIO as GPIO
import smbus as sb
import wiringpi as wp
import os
import sys
import time
import struct
import json
HDC1000_RDY_PIN = 27
HDC1000_ADDRESS = 0x40
HDC1000_CHANNEL = 1
INTERVAL = 1
CONFIG_POINTER = 0x02
CONFIG_MSB = 0x10
CONFIG_LSB = 0x00
TEMPERATURE_POINTER = 0x00
HUMIDITY_POINTER = 0x01
GPIO.setmode(GPIO.BOARD)
GPIO.setup(13, GPIO.IN)
i2c = wp.I2C()
def overwrite(s):
sys.stdout.write("r\033[K" + s)
sys.stdout.flush()
class HDC1000:
def __init__(self):
self.hdc1000 = sb.SMBus(HDC1000_CHANNEL)
# self.fd = os.open("/dev/i2c-%d" % HDC1000_CHANNEL, os.O_RDWR, 0)
self.fd = i2c.setup(HDC1000_ADDRESS)
self.fromcgi = "REQUEST_METHOD" in os.environ
def config(self):
setting = [CONFIG_POINTER, CONFIG_MSB, CONFIG_LSB]
self.hdc1000.write_i2c_block_data(HDC1000_ADDRESS, setting[0], setting[1:])
def read_value(self):
def parse(mix_val):
mix_val[0] = mix_val[0] * 165.0 / float(0xffff) - 40.0
mix_val[1] = mix_val[1] * 100.0 / float(0xffff)
return mix_val
self.hdc1000.write_i2c_block_data(HDC1000_ADDRESS, TEMPERATURE_POINTER, [])
while GPIO.input(13):
if not self.fromcgi:
overwrite("測定中...")
time.sleep(0.01)
data = [((struct.unpack('4B', os.read(self.fd, 4)))[0] << 8 |
(struct.unpack('4B', os.read(self.fd, 4)))[1]),
((struct.unpack('4B', os.read(self.fd, 4)))[2] << 8 |
(struct.unpack('4B', os.read(self.fd, 4)))[3])]
if data[0] < 0 or data[1] < 0:
if not self.fromcgi:
overwrite("エラー: 値が取得できません")
return None
else:
return parse(data)
def get_value(self):
data = HDC1000.read_value(self)
if data is not None:
return {"temp": data[0], "humi": data[1]}
else:
return None
sensor = HDC1000()
sensor.config()
if sensor.fromcgi:
sys.stdout.write("Content-Type: application/javascript; charset=utf-8nn")
value = sensor.get_value()
if value is not None:
sys.stdout.write(json.dumps(value))
else:
sys.stdout.write(json.dumps({"error": "Can't read value"}))
else:
try:
while True:
value = sensor.read_value()
if value is not None:
overwrite("温度: " + str(value[0]) + "℃, 湿度: " + str(value[1]) + "%")
else:
overwrite("エラー: 有効な値が取得できません")
break
time.sleep(INTERVAL)
except KeyboardInterrupt:
print "n"
os.close(sensor.fd)
GPIO.cleanup()
get_lps25h.py 気圧取得用 :
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import smbus as sb
import os
import sys
import time
import json
INTERVAL = 1
LPS25H_ADDRESS = 0x5c
LPS25H_CHANNEL = 1
WHO_AM_I = 0x0f
CTRL_REG1 = 0x20
PRESS_POUT_XL = 0x28
PRESS_OUT_L = 0x29
PRESS_OUT_H = 0x2a
TEMP_OUT_L = 0x2b
TEMP_OUT_H = 0x2c
def overwrite(s):
sys.stdout.write("r\033[K" + s)
sys.stdout.flush()
class LPS25H:
def __init__(self):
self.lps25h = sb.SMBus(LPS25H_CHANNEL)
self.fromcgi = "REQUEST_METHOD" in os.environ
self.esta = False
def config(self):
whoami = self.lps25h.read_byte_data(LPS25H_ADDRESS, WHO_AM_I)
if whoami != 0xbd:
if not self.fromcgi:
overwrite("エラー: センサと通信できません")
self.esta = False
return
else:
self.esta = True
self.lps25h.write_i2c_block_data(LPS25H_ADDRESS, CTRL_REG1, [0x90])
if not self.fromcgi:
overwrite("測定中...")
time.sleep(0.5)
def read_value(self):
def conv(d):
d[0] = float(d[0]) / float(0xfff)
if d[1] & 0x8000:
d[1] = -((d[1] - 1) ^ 0xffff)
d[1] = float(d[1]) / 480.0 + 42.5
return d
if self.esta:
data = [
(self.lps25h.read_i2c_block_data(LPS25H_ADDRESS, PRESS_POUT_XL, 1)[0] |
self.lps25h.read_i2c_block_data(LPS25H_ADDRESS, PRESS_OUT_L, 1)[0] << 8 |
self.lps25h.read_i2c_block_data(LPS25H_ADDRESS, PRESS_OUT_H, 1)[0] << 16),
(self.lps25h.read_i2c_block_data(LPS25H_ADDRESS, TEMP_OUT_L, 1)[0] |
self.lps25h.read_i2c_block_data(LPS25H_ADDRESS, TEMP_OUT_H, 1)[0] << 8)]
if not (data[0] < 0 or data[1] < 0):
return conv(data)
else:
return None
else:
return None
def get_value(self):
data = LPS25H.read_value(self)
if data is not None:
return {"press": data[0], "temp": data[1]}
else:
return None
sensor = LPS25H()
sensor.config()
if sensor.fromcgi:
sys.stdout.write("Content-Type: application/javascript; charset=utf-8nn")
value = sensor.get_value()
if value is not None:
sys.stdout.write(json.dumps(value))
else:
sys.stdout.write(json.dumps({"error": "Can't read value"}))
else:
try:
while True:
value = sensor.read_value()
if value is not None:
overwrite("気圧: %fhPa, 温度: %f℃" % (value[0], value[1]))
else:
overwrite("エラー: 有効な値が取得できません")
break
time.sleep(INTERVAL)
except KeyboardInterrupt:
print "n"
続いてサーバサイドのサンプルコードがこちら
log_atmos.py ログ保存用 :
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import requests
import json
from time import time
r0 = requests.get("http://address.to.raspi.documentroot/path/to/cgi/get_hdc1000.py").json()
r1 = requests.get("http://address.to.raspi.documentroot/path/to/cgi/get_lps25h.py").json()
f = open("/path/to/log/atmos.log", "a")
f.write("%sn" % json.dumps({"time": time(), "hdc1000": r0, "lps25h": r1}))
f.close()
[/code]
[code lang="py" title="hold_atmos.py 値保持用"]
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import requests
import json
from time import time
r0 = requests.get("http://address.to.raspi.documentroot/path/to/cgi/get_hdc1000.py").json()
r1 = requests.get("http://address.to.raspi.documentroot/path/to/cgi/get_lps25h.py").json()
f = open("/path/to/var/atmos.txt", "w")
json.dump({"time": time(), "hdc1000": r0, "lps25h": r1}, f)
f.close()
これら二つのファイルを cron に登録して定期実行します。
$ sudo nano /etc/crontab
crontab :
# 以下を追記
* * * * * root /path/to/log_hdc1000_lps25h_from_raspi01.py
* * * * * root for i in `seq 0 5 59`;do (sleep ${i} ; /path/to/hold_hdc1000_lps25h_from_raspi01.py) & done;
このサンプルでは、上の行は1分に1回、下の行は5秒に一回コマンドが実行されます。
ついでに、値を保持したファイルを読み込んでJSONを返すサンプルがこちら このコードをJavaScriptから叩きます
get_atmos_from_hold_file.py :
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import sys
f = open("/path/to/var/atmos.txt")
sys.stdout.write("Content-Type: application/javascript; charset=utf-8nn")
sys.stdout.write("callback(%s)" % f.readline())
JavaScriptはこちら
atmos.js :
$(function() {
get();
setInterval(function() {
get();
}, 5000)
})
function getReadableValue(value) {
var l = Math.floor(value).toString();
var s = Math.floor(value * 100).toString().slice(-2);
return l + "." + s
}
function get() {
$.ajax({
url: "/path/to/get_atmos_from_hold_file.py",
dataType: "jsonp",
jsonp: false,
jsonpCallback: "callback",
timeout: 1000
}).done(function(data) {
$("#temp").text(getReadableValue(data.hdc1000.temp) + "[℃]")
$("#humi").text(getReadableValue(data.hdc1000.humi) + "[%]")
$("#press").text(getReadableValue(data.lps25h.press) + "[hPa]")
});
}