Raspberry Pi -based sensor station

README.md

Raspberry Pi -based sensor station

This is mostly documentation for myself. Feel free to use any of it if it helps, though.

Hardware

• Any Raspberry Pi device (1, 2 or 3; not sure about the 0)
• A Wi-Fi adapter known to work with the Pi (mine is Asus USB-N10 Nano for 20 €)
• 1-Wire USB Adapter (mine is DS9490R, though appears as "Dallas Semiconductor DS1490F 2-in-1 Fob, 1-Wire adapter" on lsusb)
• A bunch of 1-Wire temperature sensors (mine are the waterproof DS18B20 kind)

Software

• Image an SD card with Raspbian (LITE is fine)
• Resize disk with sudo raspi-config (and update locales etc)
• Set up the 1-Wire filesystem:
  • sudo apt-get install owfs
  • sudo mkdir /mnt/1wire && sudo chown pi:pi /mnt/1wire/
  • sudo vim /etc/owfs.conf (see below)
  • sudo vim /etc/init.d/owfs && sudo chmod a+x /etc/init.d/owfs && sudo update-rc.d owfs defaults (see below)
  • sudo vim /etc/fuse.conf (see below)
• Check to see the sensors are visible on owfs (use head instead of cat): head /mnt/1wire/28.5F7CE1040000/temperature should print out something like 23.4375 (depending on the sensor address and the current temperature, of course)
• Set up a cronjob for collecting stats: * * * * * ~/bin/collect-stats > /dev/null
• Set up Graphite scripts:
  • ~/bin/send-stat (see below)
  • ~/bin/collect-stats (see below)
  • ~/bin/ping-rt-avg (see below)
• Set up a cronjob for collecting counter stats: @reboot ~/bin/collect-counter.py > /dev/null

collect-counter.py

#!/usr/bin/env python

import RPi.GPIO as GPIO
import time
import datetime
from subprocess import call

REED_SWITCH_PIN = 15 # RasPi GPIO pin to use (see https://www.raspberrypi.org/documentation/usage/gpio/)
FLUSH_INTERVAL = 60 # seconds
FLUSH_SCRIPT = "/home/pi/bin/send-stat"
FLUSH_LABEL = "home.counter"

GPIO.setmode(GPIO.BCM) # Broadcom pin-numbering scheme
GPIO.setup(REED_SWITCH_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) # Set pin as input with pull-up

flushedAt = time.time()
counter = 0
prevState = 1

# Enter main loop
try:
  while 1:

    # Read current value of the switch
    currentState = GPIO.input(REED_SWITCH_PIN)

    # Increment counters on change
    if (currentState != prevState):
      prevState = currentState
      if currentState == 0:
        counter += 1
        print datetime.datetime.now().isoformat() + " counter = " + str(counter)

    # Every N seconds, flush the counter
    if time.time() - flushedAt > FLUSH_INTERVAL:
      print datetime.datetime.now().isoformat() + " FLUSH"
      call([ FLUSH_SCRIPT, FLUSH_LABEL, str(counter) ])
      counter = 0
      flushedAt = time.time()

    # Sample every 100 ms (reading the switch without ANY delay causes false positives)
    time.sleep(0.01)

# Do GPIO cleanup on Ctrl + C
except KeyboardInterrupt:
  GPIO.cleanup()

collect-stats

#!/bin/bash

PATH=$PATH:~/bin

send-stat hosts.$(hostname).load $(cat /proc/loadavg) # since loadavg gives space-separated values, only the first such value is sent
send-stat hosts.$(hostname).uptime $(expr $(cat /proc/uptime | sed "s/\..*//") / 86400) # convert from seconds to days
send-stat hosts.$(hostname).cputemp $(expr $(cat /sys/class/thermal/thermal_zone0/temp) / 1000)

send-stat home.temps.28_5F $(head /mnt/1wire/28.5F7CE1040000/temperature)
send-stat home.temps.28_89 $(head /mnt/1wire/28.89BBE1040000/temperature)
send-stat home.temps.28_FF $(head /mnt/1wire/28.FF9768601404/temperature)

send-stat hosts.$(hostname).pings.router $(ping-rt-avg 192.168.1.1)
send-stat hosts.$(hostname).pings.graphite $(ping-rt-avg $GRAPHITE_HOST)
send-stat hosts.$(hostname).pings.google $(ping-rt-avg google.com)

fuse.conf

# /etc/fuse.conf - Configuration file for Filesystem in Userspace (FUSE)

# Set the maximum number of FUSE mounts allowed to non-root users.
# The default is 1000.
#mount_max = 1000

# Allow non-root users to specify the allow_other or allow_root mount options.
user_allow_other

owfs

#!/bin/sh
### BEGIN INIT INFO
# Provides: owfs
# Required-Start: $remote_fs $syslog $network $named
# Required-Stop: $remote_fs $syslog $network $named
# Should-Start: owfs
# Should-Stop: owfs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: 1-wire file system mount & update daemon
# Description: Start and stop 1-wire file system mount & update daemon.
### END INIT INFO
CONFFILE=/etc/owfs.conf
DESC="1-Wire file system mount"
NAME="owfs"
DAEMON=/usr/bin/$NAME
case "$1" in
start)
echo "Starting $NAME"
$DAEMON -c $CONFFILE
;;
stop)
echo "Stopping $NAME"
killall $NAME
;;
*)
echo "Usage: $N {start|stop}" >&2
exit 1
;;
esac
exit 0

owfs.conf

# Sample configuration file for the OWFS suite for Debian GNU/Linux.
#
#
# This is the main OWFS configuration file. You should read the
# owfs.conf(5) manual page in order to understand the options listed
# here.

######################## SOURCES ########################
#
# With this setup, any client (but owserver) uses owserver on the
# local machine...
! server: server = localhost:4304
#
# ...and owserver uses the real hardware, by default fake devices
# This part must be changed on real installation
#server: FAKE = DS18S20,DS2405
#
# USB device: DS9490
server: usb = all
#
# Serial port: DS9097
#server: device = /dev/ttyS1
#
# owserver tcp address
#server: server = 192.168.10.1:3131
#
# random simulated device
#server: FAKE = DS18S20,DS2405
#
######################### OWFS ##########################
#
mountpoint = /mnt/1wire
allow_other
#
####################### OWHTTPD #########################

http: port = 2121

####################### OWFTPD ##########################

ftp: port = 2120

####################### OWSERVER ########################

server: port = localhost:4304

ping-rt-avg

#!/bin/bash

# Note: you may have to $ sudo apt-get install iputils-ping

ping -c 3 $1 | grep min/avg/max/mdev | cut -d / -f 5 # 5th field == avg

send-stat

#!/bin/bash

GRAPHITE_HOST=192.168.1.2
GRAPHITE_PORT=2003

echo "$1 $2 $(date +%s)" | nc $GRAPHITE_HOST $GRAPHITE_PORT
echo "send-stat: $1=$2"

I followed your detailed instructions and I don't see the sensors as you point out in this step:
Check to see the sensors are visible on owfs (use head instead of cat): head /mnt/1wire/28.5F7CE1040000

I am using an RP3 running Stretch. I also have the same 1-Wire USB Adapter, DS9490R, and it also shows up as "Dallas Semiconductor DS1490F 2-in-1 Fob, 1-Wire adapter" on lsusb.

I am not aware of any kernal modifications I may (or may not have made). Do you have any ideas on what I am missing.

I appreciate your posting of the detailed instructions and code.