Brief description of the logger hardware/software used to measure temperature and air pressure.

Webbased GUI:


The online GUI is based on html and php using google charts as graph engine.

The main parts are an Arduino Mega with Ethernet shield and a small pcb.
The air pressure is measured using an Adafruit MPL115A2 which connects to the Arduino via I2C.

Temperatures are measured in all indoor rooms and oudoor using Maxim/Dallas DS18S20 onewire circuits.
All additions to the Arduino are made via the pin headers.
The pcb containins 2 leds (heartbeat and error), a push button and one-wire pullup resistor.


The software running in the Arduino is developed for the sole purpose of logging data and uploading the data to a MySQL database using a webserver php page.
Arduino libraries for DS18S20 and MPL115A2 are used to interface the hardware.

During startup, registration of the temperature sensors are made to connect a certain sensor to its position in the house. The information is stored in the Arduino eeprom.
The pushbutton is used to empty the eeprom of the Arduino if pushed during boot sequence.

Temperature sensor registration procedure:
Remove all sensors except one (for me the fist one is outdoor sensor). Press the pushbutton to clear the eeprom and boot the Arduino. The software will find the address of the sensor and registrate that address as sensor number 1. Insert sensor number 2 (for me master bedroom) and reboot the Arduino. The Arduino will find 2 sensors and verify one of them to already be registered as outdoor and and the other one as a new sensor and registrate this sensor as sensor number 2. Insert sensor number 3 (TV-room) and make a reboot, continiue with one sensor at a time until all sensors are registered. Maximum number of sensors catered for in eeprom are 10, but can easily be expanded with a numberOfSensors define.

Sensors list:
sensor 1 - outdoor
sensor 2 - master bedroom
sensor 3 - TV-room
sensor 4 - living room
sensor 5 - hall
sensor 6 - kitchen
sensor 7 - Victorias room
sensor 8 - Vincents room
sensor 9 - Viggos room
sensor 10 - not used

Installed in server warderobe:


Temp sensor:


Temp sensor installed:


Arduino + ethernet shield:


PCB:



Barometer: