Requirements
ds18s20 Temperature Sensor
Download http://www.pjrc.com/teensy/arduino_libraries/OneWire.zip and copy it to your libs directory. On OSX its the following:
wget http://www.pjrc.com/teensy/arduino_libraries/OneWire.zip
unzip OneWire.zip
mv OneWire ~/Documents/arduino/libraries/
You can test if this is installed correctly by restarting the Arduino IDE and you should see the following from the Sketch -> Include Library from the top menu.
Next grab the drivers for the light sensor, I am using a TSL2561.
wget https://github.com/adafruit/Adafruit_Sensor/archive/1.0.2.zip
unzip Adafruit_Sensor-1.0.2.zip
mv Adafruit_Sensor-1.0.2 ~/Documents/arduino/libraries/Adafruit_Sensor
wget https://github.com/adafruit/Adafruit_TSL2561/archive/1.0.0.zip
unzip Adafruit_TSL2561-1.0.0.zip
mv Adafruit_TSL2561-1.0.0 ~/Documents/arduino/libraries/Adafruit_TSL2561
You can test these are installed correctly as they will appear in the “Recommended libraries” section in the screenshot above once you restart the Arduino IDE.
The following code is mostly from http://playground.arduino.cc/Learning/OneWire I have a few really minor changes.
The code below is all will read from the two sensors and output JSON over the serial port.