[[Image(distVera.png, align=right, width=300px)]]
= Distance sensor (HC-SR04) =

== Software ==
You can download the Arduino sketch here:\\
http://code.mios.com/trac/mios_arduino-sensor/browser/trunk/Arduino/DistanceSensor

Before downloading the sketch to the Arduino you need to select a unique RADIO_ID (see top of sketch source code). The RADIO_ID must be unique in your radio network and is also used on the Vera side to distinguish between different sensors (1-255). 
After updating RADIO_ID and downloading the code you should be ready to go.
Adjust the measure interval by updating SLEEP_TIME define at the top of the sketch file. 

This sensor requires you to upload the following device files to Vera as well.\\
http://code.mios.com/trac/mios_arduino-sensor/browser/trunk/Vera\\
D_DistanceSensor1.xml\\
D_DistanceSensor1.json\\
S_DistanceSensor1.xml\\

== Wire things up ==
Follow the instructions in ConnectingRadioModule to connect radio module.

The HC-SR04 sends out short ultrasonic pulses and registers when the sound echo comes back. By knowing the speed of sound you can easily calculate the distance. 
To connect the HC-SR04 sensor to the Arduino board follow these instructions:\\
Connect VCC of the HC-SR04 sensor to +5V\\
Connect Echo to digital pin 5 of the Arduino board\\
Connect Trig to digital pin 6 of the Arduino board\\
Connect GND to Arduino ground\\

== Hardware - Purchase guide ==

To build this sensor you'll need one arduino + radio specified in the base kit found here:\\
http://code.mios.com/trac/mios_arduino-sensor/wiki/WikiStart#Buyingguide\\
With the following additional parts:

1x Distance Sensor HC-SR04\\
http://www.aliexpress.com/item/Free-shipping-2pcs-Ultrasonic-Module-HC-SR04-Distance-Measuring-Transducer-Sensor-for-Arduino-Samples-Best-prices/690139020.html

TOTAL SENSOR PRICE: $7,6 (arduino + radio) + $2.42 (HC-SR04) = '''$10'''

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