A combination of arduino and web to log/view sensor data (i.e. temperature).

Several Sensors (DS18B20 temp sensors) are coupled via One-Wire to your arduino. It will read the sensor values frequently and upload them to your Webserver. Via http:... you can access this sensor values as (hopefully) neat graphs or simple as values.

• Arduino DUE (former versions used an Arudino UNO)
• ESP8266 Wifi-module (former Versions used a Wifly-shield)
• Sensor-shield (not necessary but it makes some connections easier)
• DS18B20 temperature sensors

To see if it fits your needs, have a look at this demo installation:

Desktop view

Simpe View, for mobile

1. Solder/connect your sensors to arduino
2. Install the necessary arduino libraries
3. Make your changes in arduino-project (preferences.h)
4. Copy php-css-js files to your webspace and make corresponding changes

There are few things to be changed before you can start.

• All points to be changed are in preferences.h
• Network config (I used no DHCP because the WiFly-shield had issues in combination with my router)
• SEKRET You need to set a simple string to obfuscate the URL so that not everybody can add faulty sensor values. Sometimes this is called this API-Key. This is not secure, so don`t use this SW to control critical Systems!

• VIEWSEKRET is needed to see the website incl. the sensor values
• ADDSEKRET is needed to add new sensor values --> this is the same like in arduino project
• Raw and readable names of your sensors are entered as an array at the beginning of index.php (Every unknown sensor will be displayed as such beside the graph.)
• There are many things to be changed for your use case. They are marked with "TBC" in arduino and php source code.

This Project uses materialize design and Chart.js for graphs.

For materialize documentation, see the materialize website.

For complete Chart.js documentation, see the Chart.js home page.

• OneWire for basic communication with DS18B20-Sensors
• Dallas Temperature library to init sensors with resolution etc. and read values
• Metro For pseudo scheduling of tasks
• ITEADLIB_Arduino_WeeESP8266 to use the Wifi-module

• Some Arduio DUE don`t start after power-up until reset is pressed. You can use a capacitor to make a simple workaround, thanks to martinyim from arduino-forum
• The Wifi-module will need high currents during data-transfer. So it`s a good idea to not power it through arduino but with a secondary power source. I used the lazy solution and added some big capacitors to overcome the short times of intense power consumption.
• I use the watchdog to reset the whole system if any transmission problems occur. But in the last Arduino-IDE the watchdog for arduino DUE is disabled. You need to enable it. That´s easy once you found the relevant files on your system. See here

• Authentication is not supported now because Arduino Wifly lib or Wifly-Shield does not support https and I'm not aware of another solution with similar security.
• HTTPS is not available, looks like the used hardware does not suport this.
• Gaps of sensor-values. When there is not sensor value/signal for some time, you will not notice this in the graph, because all available values are taken into account without checking the available frequency of sensor values
• Instead of the built in watchdog you could use a hardware watchdog to completely reset arduino and WiFly in case of any error. My last version used this and it was a pretty good idea for a system you cannot touch for a long time.