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Home Automation - Sensors

Star Useful sensors and switches to find out what's happening in your house.

Often these connect to a Phidgets interface board to allow the PC to see the readings.  Some sensors types (eg motion sensor) switch 115V so you need to use a USB wart to derive a 5V logic signal.


Air Temperature sensor

Phidgets Air Temperature Sensor 

http://www.phidgets.com/products.php?category=35&product_id=1124_0     $15

Temperature sensor with a range of -30°C to +80°C with a typical error of ±0.75°C in the 0°C to 80°C range.

Make sure that Ratiometric mode is used.

Need to decide what temperature change amount causes the UI to be updated.


Waterproof Temperature sensor

Waterproof Temperature Sensors 

http://www.amazon.com/Vktech-DS18b20-Waterproof-Temperature-Transmitter/dp/B00CHEZ250/ref=pd_sim_86_8?&ie=UTF8&refRID=0N3A7KVJ60GAAJNTDJAA        $6.99 for 5

5V power.  5V use a 4.7k resistor between signal and VCC.
Output leads:  Red (VCC), Yellow(DATA) , Black(GND)  (Possibly Red(VCC) Yellow(GND) Green(DATA)).
Data sheet:  http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf
For more information on how to use, see:
http://www.hacktronics.com/Tutorials/arduino-1-wire-tutorial.html  http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf  http://www.atmel.com/Images/doc2579.pdf  http://mbed.org/users/snatch59/notebook/onewirecrc/ 
Can use the Microsoft OneWire library.


Light sensor

Temperature Sensor Board 

http://www.phidgets.com/products.php?category=6&product_id=1142_0    $7

The 1142 Light sensor can measure ambient light up to 1000 lux (roughly equivalent to the typical lighting in a studio, or the sky on an overcast day).  Each sensor has been individually calibrated, and a label has been applied to the back of the board with a calibration value which can be used in your calculations to increase measurement accuracy.  Some light sensors report drastically different values depending on the type of light being detected.  The 1142 light sensor, however, only differs by a factor of 1.2 when measuring fluorescent light versus incandescent.  If you need a larger measurement range, take a look at the 1143 – Light Sensor 70,000 lux.

Just plug it into an analog input on a sensor board.  5VDC comes down the sensor cable from the sensor board.

User guide:  http://www.phidgets.com/docs/1142_User_Guide


Analog sensor cable

Sensor analog cable 

http://www.phidgets.com/products.php?product_id=3034    $1.50

This is just purchased to get the right connector for wiring up your own analog sensors.


Soil Moisture sensor

Soil Moisture Sensor 

http://www.amazon.com/sunkee-Soil-Hygrometer-Moisture-Sensor/dp/B00AYCNEKW/ref=pd_sim_328_11?ie=UTF8&refRID=1JG43TNW4B65HY89XJFD        $4.98

http://www.miniinthebox.com/fc-28-d-soil-hygrometer-detection-module-soil-moisture-sensor-blue_p685424.html   $2.99

Module Output is high level when there is a soil moisture deficit.

Feed it 5VDC from a power supply.

Dual output mode:  analog output more accurate.
Power indicator (red) and digital switching output indicator (green).

Some people complained about corrosion.  Either tin the probes with solder or use a stainless steel screw instead of the actual probe.

Do NOT apply current to the sensor continuously or it will send the metal ions from the plated sensor into the soil.  You need to only power it up for the duration of the measurement.  That means you probably need a relay on the 5VDC to it.

Pin Definition VCC 5V,  GND,  GND,  DO Digital output interface (0 and 1),  AO Analog output interface.


Humidity sensor

Humidity sensor raw 

http://smile.amazon.com/Sensitivity-Control-Temperature-Humidity-20-90-RH/dp/B00BXWUWRA/ref=pd_sim_469_43?ie=UTF8&refRID=1CC9QX1V2PMSZ5CPJHZQ         $2.66


Magnetic sensor switch

Magnetic Sensor Switch 

http://www.phidgets.com/products.php?category=32&product_id=3562_0        $2.50

Use a 5VDC power supply to one end and connect the other end to a digital input on the sensor board.

The 3562 magnetic contact switch is very small and is designed for surface mounted installations. The switch handles gaps of up to 12mm (1/2 inch) between the magnet and the switch. The switch will turn the digital input "on" when the magnet is within 12mm of the switch, and will turn "off" when the contact is broken by moving the magnet more than 13mm away.


Motion detector

Motion Sensor Decora 


Typically these are available for about $11.  They are used to switch on a 115V socket.  Use a USB wart to derive a 5V logic signal that can be fed into a digital input for the HouseMaster central controller.

Use a decora style 115V module and then use a USB wart to derive a 5V logic signal.



I/O Linc - INSTEON Freeze Sensor Kit $65