Pressure/Temperature/Weather forecast sensor (BMP085)

Software

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

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. After updating RADIO_ID and downloading the code you should be ready to go. This sensor sleeps most of the time. You can change the sleep interval by updating SLEEP_TIME define at the top of the 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_BarometerSensor1.xml
D_BarometerSensor1.json
S_BarometerSensor1.xml

Wire things up

Follow the instructions in ConnectingRadioModule to connect radio module.

To connect the BMP085 sensor to the Arduino board follow these instructions:
Connect VCC of the BMP085 sensor to 3.3V (NOT 5.0V!)
Connect GND to Ground
Connect SCL to i2c clock - on 168/328 Arduino Nano/Uno/Duemilanove/etc thats Analog 5
Connect SDA to i2c data - on 168/328 Arduino Nano/Uno/Duemilanove/etc thats Analog 4
EOC is not used, it signifies an end of conversion
XCLR is a reset pin, also not used here

Hardware - Purchase guide

This is the stuff you need to purchase to build the PressureSensor. Note that I've provided links to the things I bought during the development. You might find it cheaper somewhere else. Also note that you might need to buy like 10x of some items to get the price specified.

1x Cheap Arduino Nano without serial interface and usb connector
​http://www.aliexpress.com/item/16Pcs-Lot-Pro-Mini-Module-Atmega328-5V-16M-For-Arduino-Compatible-Nano/710613095.html

8x Dupont cable Female->Female for radio module (and you might need 4 extra cables for your pressure sensor)
​http://www.aliexpress.com/item/New-Female-To-Female-40-pcs-Wire-Cable-Line-1p-1p-Pin-Connector-20cm-2-54mm/1045212486.html

1x NRF24L01+ wireless data transmission module 2.4Ghz
​http://www.aliexpress.com/item/Free-shipping-NRF24L01-wireless-data-transmission-module-2-4G-the-NRF24L01-5PCS-LOT-upgrade-version-New/603756080.html

1x BMP085 Pressure sensor
​http://www.aliexpress.com/item/Free-shipping-BMP085-Altimeter-Atmospheric-Pressure-Module-for-Arduino/961254477.html

(You might later need some housing and transformer or battery compartment as well)

TOTAL SENSOR PRICE: $3,99 + $0.93 + $0,6 + $3,8 = $9,32

To download code to the cheapest Arduino Nano sensors (that is missing the serial USB port) you need to buy one of following as well. It is only attached while downloading code and can be reused between sensors.

1x Serial to USB adapter to download code to cheap Arduino Nanos
​http://www.aliexpress.com/item/Free-Shipping-FT232RL-USB-To-Serial-Adapter-Module-USB-TO-232-For-Arduino-Download-Cable/827218126.html