The adapter ds18b20 enables the direct integration of 1-wire temperature sensors of the type DS18B20 or similar into ioBroker.
An appropriate hardware with support for the 1-wire bus is required (e.g. Raspberry Pi). Also the 1-wire bus must be properly functional on the system (sensors listed in /sys/bus/w1/devices/).
An example of the connection of DS18B20 sensors to a Raspberry Pi can be found below.
- Read the current temperature value
- Auto detect of the connected sensors
- Detection of errors while reading a sensor (checksum, communication error, device disconnected)
- Query interval customizable per sensor
- Single senors may be disabled
- Rounding and conversion of the measured value customizable per sensor
- Support for sensors at remote systems using the remote client
The adapter is available in the stable and latest repository.
Alternatively, the latest development version can be installed using the GitHub URL https://github.com/crycode-de/ioBroker.ds18b20.git.
This is recommended in only some cases!
In the adapter configuration, a Default query interval can be specified in milliseconds for all sensors. Minimum is 500.
In addition, the Path of the 1-wire devices can be adjusted if necessary.
Default is /sys/bus/w1/devices, where sensors on all bus masters will be detected.
Alternatively you may set the direct path ot one bus master, e.g. /sys/bus/w1/devices/w1_bus_master1. Then you will get only sensors for this single bus master.
The sensors can be added to a table manually or by Search for Sensors.
The Address is the 1-wire address/ID of the sensor and determines the object ID.
As an example, a sensor with the address 28-0000077ba131 gets the object ID ds18b20.0.sensors.28-0000077ba131.
The Name is used to identity the sensor. It's freely selectable by you.
The Remote system ID is empty for directly attached sensors or the ID of the remote system for sensors attached to a remote system.
For each sensor a custom Query interval may be specified in milliseconds.
If this field is left blank, the default query interval will be used. Minimum is 500.
The Unit defines the stored unit in the ioBroker object for the value.
Default is °C.
Via Factor and Offset it is possible to adjust the value read by the sensor according to the formula value = (value * factor) + offset.
The Decimals indicate how many places after the decimal point the value is rounded. The rounding takes place after the calculation with factor and offset.
Null on error defines how sensor read errors are handled.
If this option is set, a null value be written to the sensor state on error.
If unset, the state will not be updated on errors.
The Enabled checkbox allows you disable specific sensors separately.
An integrated server can be activated and configured for the integration of sensors at a remote system.
The Encryption key must be given to all remote systems. Using this key, the communication between the server and the clients is encrypted.
To get the temperatures from the adapter in °F you need to use 1.8 as factor and 32 as offset.
It is possible to trigger the instant reading of one or all sensors by writing to the state ds18b20.0.actions.readNow.
To trigger the reading of all sensors, write all to the state.
To trigger the reading of a single sensor, write the address or ioBroker object ID of the sensor to the state.
It is possible to send commands to the adapter to read from the sensors or search for sensors.
Via the command read or readNow, all sensors or a single sensor can be read.
If all sensors are requested, the result will contain an object with the sensor addresses mapped to the current value.
To read a single sensor, the message part must be set to the address or ioBroker object ID of the sensor. In this case the value is provided directly.
sendTo('ds18b20.0', 'read', null, (ret) => {
log('ret: ' + JSON.stringify(ret));
// ret: {"err":null,"value":{"28-0000077b9fea":21.94}}
if (ret.err) {
log(ret.err, 'warn');
}
});
sendTo('ds18b20.0', 'read', '28-0000077ba131', (ret) => {
log('ret: ' + JSON.stringify(ret));
// ret: {"err":null,"value":21.94}
if (ret.err) {
log(ret.err, 'warn');
}
});The search command will run a search for all currently connected 1-wire sensors.
The found addresses of sensors will be provided to a callback function.
sendTo('ds18b20.0', 'search', {}, (ret) => {
log('ret: ' + JSON.stringify(ret));
if (ret.err) {
log(ret.err, 'warn');
} else {
for (let s of ret.sensors) {
if (s.remoteSystemId) {
log('Sensor: ' + s.address + '@' + s.remoteSystemId);
} else {
log('Sensor: ' + s.address);
}
}
}
});With getRemoteSystems you are able to get the system IDs of all currently connected remote systems.
sendTo('ds18b20.0', 'getRemoteSystems', {}, (ret) => {
log('ret: ' + JSON.stringify(ret));
log('Verbundene Systeme: ' + ret.join(', '));
});Via the ds18b20.*.info.connection State, each adapter instance provides information on whether all configured sensors provide data.
If the last reading of all sensors was successful, this state is true.
As soon as one of the sensors has an error, this state is false.
This state will be false too if remote systems are enabled but there is a problem with the remote server.
If remote systems are enabled the state ds18b20.*.info.remotesConnected will hold a list of the currently connected remote systems.
The connection of DS18B20 temperature sensors to a Raspberry Pi is done as shown in the following figure. Note that the pullup resistor must be connected to +3.3V instead of +5V, as this would damage the GPIO. In this example the GPIO.04 (BCM) is used.
To activate the 1-Wire bus on the Raspberry Pi, add the following line in the file /boot/config.txt and then restart the Raspberry Pi.
dtoverlay=w1-gpio,gpiopin=4
If everything works, the connected sensors will be visible under /sys/bus/w1/devices/.
$ ls -l /sys/bus/w1/devices/
total 0
lrwxrwxrwx 1 root root 0 Nov 2 11:18 28-0000077b4592 -> ../../../devices/w1_bus_master1/28-0000077b4592
lrwxrwxrwx 1 root root 0 Nov 2 11:18 28-0000077b9fea -> ../../../devices/w1_bus_master1/28-0000077b9fea
lrwxrwxrwx 1 root root 0 Nov 2 10:49 w1_bus_master1 -> ../../../devices/w1_bus_master1The number of sensors that can be operated error-free on a Raspberry Pi on one wire is limited and depends on some technical conditions (e.g. the length ot the wire).
Usually the first, sometimes random, failures occur from around 10 sensors.
To use more sensors it is possible to split the sensors on multiple wires (GPIOs). Each wire needs it's own pull-up resistor.
To enable the multiple wires you simply need to add multiple entries in the file /boot/config.txt:
dtoverlay=w1-gpio,gpiopin=4
dtoverlay=w1-gpio,gpiopin=17
Each entry will create it's own w1_bus_masterX in the system.
There was a bug in the 5.10.y kernel of the Raspberry Pi since november 2020 which lead to negative temperatures be read as e.g. 4092 °C. (see GitHub Issue)
This bug was fixed in kernel 5.10.14 at 2021-02-08. (see GitHub Commit)
So a rpi-update should fix the problem.
Adapter versions until v1.2.2 these obviously wrong values are transferred to the ioBroker State.
Since v1.2.3 the adapter checks if the read values are plausible (between -80 and +150 °C) and discards unplausible values.
Starting in version 1.4.0 of ioBroker.ds18b20 it is possible to directly integrate sensors of a remote system using the ioBroker.ds18b20 remote client. You only need Node.js installed on the system for this.
In the adapter configuration you have set the checkbox Enable remote sensors. Then the adapter will create a TCP server on the given port and accept connections from remote clients.
The server-client connection will be encrypted using an aes-256-cbc algorithm.
Therefore the encryption key from the adapter configuration must be set at each client.
Then the ioBroker.ds18b20 remote client connects to the adapter and will be shown under Connected remote systems in the adapter configuration.
A setup for the ioBroker.ds18b20 remote client is provided via GitHub.
Instructions how to set up the client are includes in the adapter configuration.