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https://github.com/womoak75/opendew

temperature / humidity / dew point controlled ventilation system running on OpenWrt
https://github.com/womoak75/opendew

dewpoint humidity-sensor openwrt shellscript temperature-sensor ventilation

Last synced: 27 days ago
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temperature / humidity / dew point controlled ventilation system running on OpenWrt

Host: GitHub
URL: https://github.com/womoak75/opendew
Owner: womoak75
Created: 2024-04-12T16:34:41.000Z (9 months ago)
Default Branch: main
Last Pushed: 2024-04-13T06:03:51.000Z (9 months ago)
Last Synced: 2024-04-14T16:14:34.903Z (9 months ago)
Topics: dewpoint, humidity-sensor, openwrt, shellscript, temperature-sensor, ventilation
Language: Shell
Homepage:
Size: 37.1 KB
Stars: 0
Watchers: 1
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md

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README

# OpenDew

![overview](docs/overview.svg)

## what is it

a collection of simple shellscripts to
* collect data from external wireless temperature/humidity sensors
* calculate dewpoint temperature
* turn on/off a fan (through a smartplug)

## why

when last did you ventilate the cellar?

## why openwrt / rtl_433 / shellscript ?

the choise of the components was defined by availability in my stuff box. :)

## todo

add support for wired sensors (i2c/onewire)?

## hardware

- an OpenWRT compatible router (e.g. some from TP-Link) with USB port
- a Realtek RTL2832 based DVB dongle (https://osmocom.org/projects/rtl-sdr/wiki)
- some temperature/humidity sensors (433/868Mhz)

## software

- (os) http://openwrt.org
- (sdr) https://github.com/merbanan/rtl_433 /
- (broker) https://mosquitto.org

![flow](docs/dataflow.svg)

### mqttreader

reads rtl_433 sensor data from 'rtl_433/{hostname}/events' (rtl_433 default topic)

```json
{
"time": "2024-04-07 16:27:27.095538",
"model": "Nexus-TH",
"id": 231,
"channel": 1,
"battery_ok": 1,
"temperature_C": 27.4,
"humidity": 35
}
```

```json
{
"time": "2024-04-07 16:27:27.095538",
"model": "Bresser-3CH",
"id": 116,
"channel": 3,
"battery_ok": 1,
"temperature_C": 15.5,
"humidity": 63,
"mic": "CHECKSUM"
}
```

and publishes to 'app/dewpoint/sensors/in'

```json
{ "name": "id1-231", "temperature_C": 27.4, "humidity": 35 }
```

```json
{ "name": "id3-116", "temperature_C": 15.5, "humidity": 63 }
```

### sensormaster

reads sensor data from 'app/dewpoint/sensor/in'

```json
{ "name": "id1-231", "temperature_C": 27.4, "humidity": 35 }
```

```json
{ "name": "id3-116", "temperature_C": 15.5, "humidity": 63 }
```

uses a configuration to map from external sensor ids to internal names

```json
[
{
"name":"id3-116",
"id":"keller1"
},
{
"name":"id1-231",
"id":"aussen1stock"
}
]
```

calculate dewpoint according to temperature / humidity and publishes to 'app/dewpoint/in'

```json
{
"ts":"2024-04-07_16:27:29+CEST",
"name":"aussen1stock",
"temperature_C":27.4,
"humidity":35,
"dew":10.5808
}
```
```json
{
"ts":"2024-04-07_16:27:30+CEST",
"name":"keller1",
"temperature_C":15.5,
"humidity":63,
"dew":8.48191
}
```

### dewcalculator

read from 'app/dewpoint/in'

has a mapping where multiple indoor/outdoor sensors can be configured.

```json
{
"insensors": [
"keller1"
],
"outsensors": [
"aussen1stock"
]
}
```

when data from every sensor is available
average outdoor/indoor temperature, humidity and dewpoint are calculated.

publishes to 'app/dewpoint/out'

```json
{
"ts": "2024-04-07_16:27:32+CEST",
"dew_avg": {
"delta": -2.09889,
"indoor": 8.48191,
"outdoor": 10.5808
},
"temperature_avg": {
"indoor": 15.5,
"outdoor": 27.4
},
"humidity_avg": {
"indoor": 63,
"outdoor": 35
},
"sensors": {
"indoor": [
{
"ts": "2024-04-07_16:26:10+CEST",
"name": "keller1",
"temperature_C": 15.5,
"humidity": 63,
"dew": 8.48191
}
],
"outdoor": [
{
"ts": "2024-04-07_16:27:29+CEST",
"name": "aussen1stock",
"temperature_C": 27.4,
"humidity": 35,
"dew": 10.5808
}
]
},
"app": {
"dew_diff_min": 1.0,
"dew_diff_max": 2.3,
"room_temperature_min": 10.0
}
}

```

### dewapp

reads from 'app/dewpoint/out'

calculates if fan should be turned on/off according temperature / dewpoint data.

publishes to 'app/dewpoint/control'

```json
{
"ts":"2024-04-07_16:27:37+CEST",
"type":"control",
"fan":0
}
```

### dewcontrol

reads from 'app/dewpoint/control'

```json
{
"ts":"2024-04-07_16:27:37+CEST",
"type":"control",
"fan":0
}
```

read user provided functions from '/etc/opendew/custom.sh'

```sh

# custom user actions can be executed here

custom_fanon() {
logger "custom fan on :)"
curl http://espplug.fritz.box/cm?cmnd=Power%20on
}

custom_fanoff() {
logger "custom fan off :)"
curl http://espplug.fritz.box/cm?cmnd=Power%20off
}

custom_status_on() {
logger "custom status changed to on"
}

custom_status_off() {
logger "custom status changed to off"
}
```

executes custom_fanoff() or custom_fanon() functions (if defined).

## configuration

configfile '/etc/opendew/opendew.cfg'

```

MQTTHOST="localhost"
MQTTPORT="1883"
MQTTUSER=""
MQTTPASS=""

MQTTTOPICBASE="app/dewpoint"

MQTTREADER_INTOPIC="rtl_433/+/events"

DEW_DIFF_MAX=2.3
DEW_DIFF_MIN=1.0
ROOM_TEMP_MIN=10.0

SENSORMASTERCONFIG='[{"name":"id3-116","id":"keller1"},{"name":"id1-231","id":"aussen1stock"}]'

SENSORCONFIG='{"insensors":["keller1"],"outsensors":["aussen1stock"]}'

```
### sensor mapping (rtl_433 to internal)

```
SENSORMASTERCONFIG='[{"name":"id3-116","id":"keller1"},{"name":"id1-231","id":"aussen1stock"}]'
```
In a first step, the sensor data must be converted from the rtl_433 proprietary format into the application's own data format.

```json
// rtl_433 specific
{
"time": "2024-04-07 16:27:27.095538",
"model": "Bresser-3CH",
"id": 116,
"channel": 3,
"battery_ok": 1,
"temperature_C": 15.5,
"humidity": 63,
"mic": "CHECKSUM"
}
```
to
```json
// dew app specific
{
"name": "id3-116",
"temperature_C": 15.5,
"humidity": 63
}
```
During this process, a unique ID is also assigned to each sensor, which is then used internally. In the event of a sensor replacement (e.g., due to a defect), only the mapping to the internal name/ID needs to be changed.

The ID generation follows the following pattern:
```
id{rtl_433.channel}-{rtl_433.id}
```
e.g.
```
id:116, channel=3 -> 'id3-116'
```
### sensor mapping (internal to in/outsensor)

```
SENSORCONFIG='{"insensors":["keller1","keller2","keller3"],"outsensors":["aussen1stock","aussenterrasse"]}'
```

Indoor and outdoor sensors can be defined as 1 to n sensors each. The respective value (temperature, humidity, and dew point) is determined as the average across all configured sensors for indoor/outdoor use.

## faq

### will it also run on a 'real' linux system?

Probably.
The shellscripts should run on any linux system, but startup scripts for initd / systemd are necessary.

### is there a UI available?

No.

### how to display data?

Use your favorite home automation system.
For example: [FHEM](https://fhem.de/)

![flow](docs/temp_humidity_diagram.png)