Wifi temperature probe DS18B20


The new version of PiTherm (v60910w1 and higher) supports retrieving temperatures from other raspberry pis over a home network. You can simply build a ‘wifi temperature probe’ by using Raspberry Pi Zero W (or any other version). It will extend the distance and eliminate a need of long wirings for temperature probe DS18B20.

 

wifi temperature probe

 

Option 1. – Use our scripts

  1. Connect a temperature probe DS18b20 to Raspberry Pi according to connection diagram.
  2. Prepare an SD card – download and install the newest version of the OS Raspbian
  3. Insert the SD card into the raspberry pi and boot it up.
  4. Open the terminal and install ‘temperature sender’ :
cd /etc
sudo mkdir send
cd /etc/send
sudo wget www.raspberry-solutions.com/pitherm/upd/sender.zip
sudo mkdir sender
sudo chmod 777 *
unzip -u sender.zip
sudo rm -f sender.zip
cd /etc/send/sender

 

5. Type sudo nano settings.py ,  change the IP address and required parameters if needed (default settings = the best performance)

 

threshold_v – (Δt)  the difference between two transmitted temperatures
t_threshold_v – DO NOT CHANGE
ip_v – IP address of the PiTherm
interval_v – time interval between two readings
dif_v – sensors calibration

 

The Raspberry Pi checks temperatures every ‘interval_v‘ seconds. If absolute difference between last transmitted temperature and current temperature is higher than ‘threshold_v‘, the raspberry pi amends the value by ‘dif_v‘ and sends it to the ip address ‘ip_v‘.
wifi ds18b20 raspberry pi
Hit Ctrl+X to exit and then ‘Y’ to Save the settings.

 

6. Type sudo nano /boot/config.txt
Then scroll down to the bottom of the file, and add the line: dtoverlay=w1-gpio
Ctrl-X to save the amended file.

 

7. Create a new cron task to autorun sender by typing crontab -e
Scroll to the bottom and add line: @reboot sudo python /etc/send/sender/sender.pyc &
Hit Ctrl+X to exit and then ‘Y’ to Save the settings.

 

8. Reboot the Raspberry PI
After rebooting, all new temperature probes with the prefix “rp-” should be displayed in the PiTherm.
wifi temp probe

 

Option 2. – Create own hardware & own scripts

 

If you wish to build your own wireless temperature probe based on a different technology – 443MHz, 315MHz, 900Mhz, ESP8266 or to send data from a different system, you can do so by using HTTP method GET:

 

PITHERM_IP_ADDRESS/wifimodule.php?event=21&value=temperature_in_degrees_celsius&id=id_probe

 

for example

 

192.168.1.33/wifimodule.php?event=21&value=56.625&id=28-00042e3f23ff

 

Note: Pi Therm requires each wireless probe to send data at least once per 12 minutes, otherwise, the temperature probe will be deleted from the PiTherm.