Initial code

Signed-off-by: Julien Riou <julien@riou.xyz>

.gitignore

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+serial2mqtt.ini

.pre-commit-config.yaml

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+---
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: master
+    hooks:
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+      - id: double-quote-string-fixer
+      - id: end-of-file-fixer
+      - id: fix-encoding-pragma
+        args: ['--remove']
+      - id: requirements-txt-fixer
+      - id: trailing-whitespace
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: master
+    hooks:
+      - id: flake8
+        args: ['--max-line-length=120']
+  - repo: https://github.com/FalconSocial/pre-commit-python-sorter
+    rev: master
+    hooks:
+      - id: python-import-sorter
+        args: ['--silent-overwrite']
+  - repo: https://github.com/chewse/pre-commit-mirrors-pydocstyle
+    rev: master
+    hooks:
+      - id: pydocstyle
+        args: ['--config=.pydocstyle', '--match="(?!test_).*\.py"']
+  - repo: https://github.com/jumanjihouse/pre-commit-hooks
+    rev: master
+    hooks:
+      - id: shfmt

.pydocstyle

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+[pydocstyle]
+ignore = D100,D104,D400,D203,D204,D101,D213,D202

README.md

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+# arduino-sensors-toolkit
+
+This toolkit has been designed to be used with a DHT22 (humidity, temperature) and KY-037 (sound) sensors connected to
+an Arduino microcontroller. It is part of a self hosting project with specific needs. Feel free to fork this repository
+and update code for your needs.
+
+## sensors2serial
+
+Arduino circuit:
+
+![Circuit](static/circuit.svg)
+
+## serial2mqtt
+
+### Requirements
+
+- serial interface using sensors2serial code (ex: /dev/cuaU0 for FreeBSD, /dev/ttyACM0 for Debian)
+- MQTT broker (ex: [Mosquitto](https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-the-mosquitto-mqtt-messaging-broker-on-debian-10))
+
+### Installation
+
+- Installation on [Debian](debian/README.md)
+- Installation on [FreeBSD](freebsd/README.md)
+
+### Configuration
+
+An optional configuration file can be used with `--config <file>`. See [serial2mqtt.ini.example](serial2mqtt.ini.example).
+
+### Usage
+
+```
+python3 serial2mqtt.py --help
+```

debian/README.md

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+# Installation on Debian
+
+Install the following packages:
+- python3-serial
+- python3-paho-mqtt
+
+Then git clone this repository to **/opt/arduino-sensors-toolkit**.
+
+Create the *serial2mqtt* system user and add it to the *dialout* group to read the serial interface:
+```
+# adduser --system --disabled-password --disabled-login --home /var/lib/serial2mqtt \
+    --no-create-home --quiet --force-badname --group serial2mqtt
+# usermod -a -G dialout serial2mqtt
+```
+
+Copy the [serial2mqtt.service](serial2mqtt.service) file to **/etc/systemd/system/serial2mqtt.service**.
+
+Copy the [serial2mqtt.default](serial2mqtt.default) file to **/etc/default/serial2mqtt**.
+
+Reload systemd configuration with `systemctl daemon-reload`.
+
+Enable service with `systemctl enable serial2mqtt.service`.

debian/serial2mqtt.default

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+# Options passed as daemon argument
+#DAEMON_OPTS="-c /etc/serial2mqtt.ini -v"

debian/serial2mqtt.service

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+[Unit]
+Description=Read serial port and send sensors measurements to MQTT broker
+After=syslog.target network.target
+
+[Service]
+Type=simple
+User=serial2mqtt
+Group=serial2mqtt
+EnvironmentFile=-/etc/default/serial2mqtt
+ExecStart=/opt/arduino-sensors-toolkit/serial2mqtt.py $DAEMON_OPTS
+KillMode=process
+TimeoutSec=30
+Restart=no
+
+[Install]
+WantedBy=multi-user.target

freebsd/README.md

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+# Installation on FreeBSD
+
+Install the following packages:
+- py37-pyserial
+- py37-paho-mqtt
+
+Then git clone this repository to **/usr/local/share/arduino-sensors-toolkit**.
+
+Create the system user:
+
+```
+pw user add -n serial2mqtt -s /usr/sbin/nologin -G dialer
+```
+
+Copy [serial2mqtt.rc](serial2mqtt.rc) script to **/usr/local/etc/rc.d/serial2mqtt**.
+
+Enable service:
+```
+echo 'serial2mqtt_enable="YES"' >> /etc/rc.conf
+```

freebsd/serial2mqtt.rc

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+#!/bin/sh
+# PROVIDE: serial2mqtt
+# REQUIRE: DAEMON NETWORKING
+# BEFORE: LOGIN
+# KEYWORD: shutdown
+
+# serial2mqtt_enable (bool):	Set to YES to enable serial2mqtt
+#				Default: NO
+# serial2mqtt_conf (str):		serial2mqtt configuration file
+#				Default: ${PREFIX}/etc/serial2mqtt.ini
+# serial2mqtt_user (str):		serial2mqtt daemon user
+#				Default: serial2mqtt
+# serial2mqtt_group (str):		serial2mqtt daemon group
+#				Default: serial2mqtt
+# serial2mqtt_flags (str):		Extra flags passed to serial2mqtt
+#				Default: none
+
+. /etc/rc.subr
+
+PATH=${PATH}:/usr/local/sbin:/usr/local/bin
+
+name="serial2mqtt"
+rcvar=serial2mqtt_enable
+load_rc_config $name
+
+: ${serial2mqtt_enable:="NO"}
+: ${serial2mqtt_user:="serial2mqtt"}
+: ${serial2mqtt_group:="serial2mqtt"}
+: ${serial2mqtt_flags:=""}
+: ${serial2mqtt_conf:="/usr/local/etc/${name}.ini"}
+: ${serial2mqtt_options:="${serial2mqtt_flags}"}
+
+if [ -f ${serial2mqtt_conf} ]; then
+	serial2mqtt_options="${serial2mqtt_options} --config ${serial2mqtt_conf}"
+fi
+
+logfile="/var/log/serial2mqtt/${name}.log"
+pidfile="/var/run/${name}.pid"
+command=/usr/sbin/daemon
+start_precmd="serial2mqtt_prestart"
+start_cmd="serial2mqtt_start"
+stop_cmd="serial2mqtt_stop"
+
+serial2mqtt_prestart() {
+	install -d -o ${serial2mqtt_user} -g ${serial2mqtt_group} -m750 /var/log/serial2mqtt
+}
+
+serial2mqtt_start() {
+	echo "Starting ${name}"
+	/usr/sbin/daemon -fcr -P ${pidfile} -u ${serial2mqtt_user} -o ${logfile} \
+		/usr/local/bin/python3.7 /usr/local/share/arduino-sensors-toolkit/${name}.py ${serial2mqtt_options}
+}
+
+serial2mqtt_stop() {
+	pid=$(check_pidfile $pidfile $command)
+	if [ -n "${pid}" ]; then
+		echo "Stopping ${name} (pid=${pid})"
+		kill -- -${pid}
+		wait_for_pids ${pid}
+	else
+		echo "${name} isn't running"
+	fi
+}
+
+run_rc_command "$1"

requirements.txt

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+paho-mqtt==1.5.0
+pyserial==3.4

sensors2serial.ino

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+#include <DHT.h>
+
+#define KYPIN A0          // analog pin where KY-037 sensor is connected
+#define DHTPIN 2          // digital pin where DHT22 sensor is connected
+
+DHT dht(DHTPIN, DHT22);   // initialize DHT22 object
+
+float h;  // humidity
+float t;  // temperature
+int s;    // sound
+
+void setup()
+{
+    Serial.begin(9600);
+    dht.begin();
+}
+
+void loop()
+{
+    // sensors need some time to produce valid values
+    delay(2000);
+
+    // read values from sensors
+    h = dht.readHumidity();
+    t = dht.readTemperature();
+    s = analogRead(KYPIN);
+
+    // print "<humidity>,<temperature>,<sound>" (CSV-like)
+    // all values are numbers
+    if (!isnan(h) && !isnan(t) && !isnan(s)) {
+        Serial.print(h);
+        Serial.print(",");
+        Serial.print(t);
+        Serial.print(",");
+        Serial.println(s);
+    }
+}

serial2mqtt.ini.example

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+[mqtt]
+host = localhost
+port = 1883
+#client_id = serial2mqtt
+#topic_prefix = sensors
+#username = ***
+#password = ***
+
+[serial]
+interface = /dev/cuaU0

serial2mqtt.py

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+#!/usr/bin/env python3
+import argparse
+import configparser
+import logging
+import os
+import sys
+import time
+
+import paho.mqtt.client as paho
+import serial
+
+logger = logging.getLogger(__name__)
+
+
+def read_serial(interface):
+    try:
+        logger.debug('reading serial interface {}'.format(interface))
+        s = serial.Serial(interface)
+        s.flushInput()
+        for i in range(2):
+            data = s.readline()
+            if i > 0:
+                return data
+    except Exception as err:
+        logger.warning(str(err))
+        time.sleep(2)
+
+
+def parse_sensor_values(data):
+    """
+    Input line: <humidity>,<temperature>,<sound>
+    Output structure:
+        data = {
+            'humidity': <humidity>,
+            'temperature': <temperature>,
+            'sound': <sound>
+        }
+    """
+    humidity, temperature, sound = data.decode('utf-8').strip().split(',')
+    return {'humidity': humidity, 'temperature': temperature, 'sound': sound}
+
+
+def connect_mqtt(config):
+    """Connect to MQTT broken from MQTT config and return client"""
+    mqtt_host = config.get('host', 'localhost')
+    mqtt_port = int(config.get('port', 1883))
+    mqtt_username = config.get('username')
+    mqtt_password = config.get('password')
+    mqtt_client_id = config.get('client_id', 'serial2mqtt')
+
+    client = paho.Client(client_id=mqtt_client_id)
+    client.on_connect = on_connect
+    if mqtt_username:
+        client.username_pw_set(username=mqtt_username, password=mqtt_password)
+    logging.debug('connecting to MQTT broker at {}:{}'.format(mqtt_host, mqtt_port))
+    client.connect(mqtt_host, mqtt_port)
+    return client
+
+
+def publish(client, topic, value):
+    logger.debug('publishing to topic "{}" with value "{}"'.format(topic, value))
+    client.publish(topic, value)
+
+
+def on_connect(client, userdata, flags, rc):
+    if rc > 0:
+        logger.error(paho.connack_string(rc))
+    else:
+        logger.info('connected to MQTT broker')
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-c', '--config', help='path to configuration file', default='serial2mqtt.ini')
+    parser.add_argument('-v', '--verbose', dest='loglevel', action='store_const', const=logging.INFO,
+                        help='print more output')
+    parser.add_argument('-d', '--debug', dest='loglevel', action='store_const', const=logging.DEBUG,
+                        default=logging.WARNING, help='print even more output')
+    args = parser.parse_args()
+
+    logging.basicConfig(format='%(levelname)s: %(message)s', level=args.loglevel)
+
+    config = configparser.ConfigParser()
+    if os.path.isfile(args.config):
+        config.read(args.config)
+
+    mqtt_config = config['mqtt'] if 'mqtt' in config else {}
+    mqtt_topic_prefix = mqtt_config.get('topic_prefix', 'sensors')
+    serial_config = config['serial'] if 'serial' in config else {}
+
+    try:
+        client = connect_mqtt(mqtt_config)
+    except Exception as err:
+        logger.error('connection to MQTT broker failed: {}'.format(str(err)))
+        sys.exit(1)
+
+    try:
+        client.loop_start()
+
+        while True:
+            data = read_serial(serial_config.get('interface', '/dev/cuaU0'))
+            if data:
+                data = parse_sensor_values(data)
+                for sensor_name, value in data.items():
+                    topic = '/'.join([mqtt_topic_prefix, sensor_name])
+                    publish(client, topic, value)
+    except KeyboardInterrupt:
+        pass
+
+
+if __name__ == '__main__':
+    main()