Your Smart IOT

<p>The BMP180 device is a digital barometric pressure sensor. This is available on a small module which provides access to the sensor via the <a href="http://ift.tt/1WLPB6O" itemprop="url" target="_bank" title="I2C"><strong>I2C</strong></a> interface. This allows us to easily connect it to the <a href="http://ift.tt/1o7Ssv1" itemprop="url" target="_bank" title="Raspberry Pi"><strong>Raspberry Pi</strong></a> with a minimum of wiring.</p>
<p>My module is a small pcb measuring 15x13mm with a 5 pin header. The order of the pins may vary on other modules so keep an eye on the labels so you connect up the correct wires from the Pi.</p>
<p><img alt="BMP180 Pressure Temperature Module" class="aligncenter size-medium wp-image-4848 no-display appear" height="300" sizes="(max-width: 300px) 100vw, 300px" src="http://ift.tt/1bxpU8B" srcset="http://ift.tt/1QID3Oy 150x, http://ift.tt/1bxpU8B 300x, http://ift.tt/1LK8jLx 1000x" width="300" /></p>
<p>The BMP180 is made by Bosch and the <a href="http://ift.tt/1VK07xb">official BMP180 datasheet</a> includes all the technical details.</p>
<h2>Configure I2C Interface</h2>
<p>In order to use this module you must enable the I2C interface on the <a href="http://ift.tt/1o7SsLh" itemprop="url" target="_bank" title="Raspberry"><strong>Raspberry</strong></a> Pi as it is not enabled by default. This is a fairly easy process and is described in my <a href="http://ift.tt/1rLhdYs" title="Enabling The I2C Interface On The Raspberry Pi">Enabling The I2C Interface On The Raspberry Pi</a> tutorial.</p>
<h2>Connecting Hardware</h2>
<p>The table below shows how the module is connected to the Raspberyr Pi’s <a href="http://ift.tt/1WLPAjr" itemprop="url" target="_bank" title="GPIO"><strong>GPIO</strong></a> header (P1). Please refer to my <a href="http://ift.tt/1EAcUKZ" title="Simple Guide to the RPi GPIO Header and Pins">GPIO header guide</a> for a diagram.</p>
<table>
<tbody>
<tr>
<th>Module PCB</th>
<th>Desc</th>
<th>GPIO Header Pins</th>
</tr>
<tr>
<td>VCC</td>
<td>3.3V</td>
<td>P1-01</td>
</tr>
<tr>
<td>GND</td>
<td>Ground</td>
<td>P1-06</td>
</tr>
<tr>
<td>SCL</td>
<td>I2C SCL</td>
<td>P1-05</td>
</tr>
<tr>
<td>SDA</td>
<td>I2C SDA</td>
<td>P1-03</td>
</tr>
<tr>
<td>3.3V</td>
<td>–</td>
<td>–</td>
</tr>
</tbody>
</table>
<p>Here is a diagram of a breadboard setup. If you are connecting the module’s four pins directly to the Pi you only need four female-female wires.</p>
<p><img alt="BMP180 Module Setup" class="aligncenter size-full wp-image-4857 no-display appear" height="882" sizes="(max-width: 923px) 100vw, 923px" src="http://ift.tt/1I89hwH" srcset="http://ift.tt/1VK07xh 300x, http://ift.tt/1I89hwH 923x" width="923" /></p>
<p>The breadboard diagram uses a custom part I defined in Fritzing. Other modules are available which have different pin arrangements so make sure you are connecting the correct pins to the Pi if yours is different to the one shown in this tutorial.</p>
<p>With the device connected and the Pi powered up the “i2cdetect” command should show the device with address 0x77.</p>
<h2>Example <a href="http://ift.tt/1LK8jLD" itemprop="url" target="_bank" title="Python"><strong>Python</strong></a> Script</h2>
<p>Here is an example Python script to read pressure and temperature data from the sensor :</p>
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<div class="container">
<div class="line number1 index0 alt2"><code class="python comments">#!/usr/bin/python</code></div>
<div class="line number2 index1 alt1"><code class="python keyword">import</code> <code class="python plain">smbus</code></div>
<div class="line number3 index2 alt2"><code class="python keyword">import</code> <code class="python plain">time</code></div>
<div class="line number4 index3 alt1"><code class="python keyword">from</code> <code class="python plain">ctypes</code> <code class="python keyword">import</code> <code class="python plain">c_short</code></div>
<div class="line number5 index4 alt2"><code class="python spaces"> </code></div>
<div class="line number6 index5 alt1"><code class="python plain">DEVICE</code> <code class="python keyword">=</code> <code class="python value">0x77</code> <code class="python comments"># Default device I2C address</code></div>
<div class="line number7 index6 alt2"><code class="python spaces"> </code></div>
<div class="line number8 index7 alt1"><code class="python comments">#bus = smbus.SMBus(0)  # Rev 1 Pi uses 0</code></div>
<div class="line number9 index8 alt2"><code class="python plain">bus</code> <code class="python keyword">=</code> <code class="python plain">smbus.SMBus(</code><code class="python value">1</code><code class="python plain">)</code> <code class="python comments"># Rev 2 Pi uses 1</code></div>
<div class="line number10 index9 alt1"><code class="python spaces"> </code></div>
<div class="line number11 index10 alt2"><code class="python keyword">def</code> <code class="python plain">convertToString(data):</code></div>
<div class="line number12 index11 alt1"><code class="python spaces">  </code><code class="python comments"># Simple function to convert binary data into</code></div>
<div class="line number13 index12 alt2"><code class="python spaces">  </code><code class="python comments"># a string</code></div>
<div class="line number14 index13 alt1"><code class="python spaces">  </code><code class="python keyword">return</code> <code class="python functions">str</code><code class="python plain">((data[</code><code class="python value">1</code><code class="python plain">]</code> <code class="python keyword">+</code> <code class="python plain">(</code><code class="python value">256</code> <code class="python keyword">*</code> <code class="python plain">data[</code><code class="python value">0</code><code class="python plain">]))</code> <code class="python keyword">/</code> <code class="python value">1.2</code><code class="python plain">)</code></div>
<div class="line number15 index14 alt2"></div>
<div class="line number16 index15 alt1"><code class="python keyword">def</code> <code class="python plain">getShort(data, index):</code></div>
<div class="line number17 index16 alt2"><code class="python spaces">  </code><code class="python comments"># return two bytes from data as a signed 16-bit value</code></div>
<div class="line number18 index17 alt1"><code class="python spaces">  </code><code class="python keyword">return</code> <code class="python plain">c_short((data[index]<<</code> <code class="python value">8</code><code class="python plain">)</code> <code class="python keyword">+</code> <code class="python plain">data[index</code> <code class="python keyword">+</code> <code class="python value">1</code><code class="python plain">]).value</code></div>
<div class="line number19 index18 alt2"></div>
<div class="line number20 index19 alt1"><code class="python keyword">def</code> <code class="python plain">getUshort(data, index):</code></div>
<div class="line number21 index20 alt2"><code class="python spaces">  </code><code class="python comments"># return two bytes from data as an unsigned 16-bit value</code></div>
<div class="line number22 index21 alt1"><code class="python spaces">  </code><code class="python keyword">return</code> <code class="python plain">(data[index]<<</code> <code class="python value">8</code><code class="python plain">)</code> <code class="python keyword">+</code> <code class="python plain">data[index</code><code class="python keyword">+</code><code class="python value">1</code><code class="python plain">]</code></div>
<div class="line number23 index22 alt2"></div>
<div class="line number24 index23 alt1"><code class="python keyword">def</code> <code class="python plain">readBmp180Id(addr</code><code class="python keyword">=</code><code class="python plain">DEVICE):</code></div>
<div class="line number25 index24 alt2"><code class="python spaces">  </code><code class="python comments"># Register Address</code></div>
<div class="line number26 index25 alt1"><code class="python spaces">  </code><code class="python plain">REG_ID    </code> <code class="python keyword">=</code> <code class="python value">0xD0</code></div>
<div class="line number27 index26 alt2"></div>
<div class="line number28 index27 alt1"><code class="python spaces">  </code><code class="python plain">(chip_id, chip_version)</code> <code class="python keyword">=</code> <code class="python plain">bus.read_i2c_block_data(addr, REG_ID,</code> <code class="python value">2</code><code class="python plain">)</code></div>
<div class="line number29 index28 alt2"><code class="python spaces">  </code><code class="python keyword">return</code> <code class="python plain">(chip_id, chip_version)</code></div>
<div class="line number30 index29 alt1"><code class="python spaces">  </code></div>
<div class="line number31 index30 alt2"><code class="python keyword">def</code> <code class="python plain">readBmp180(addr</code><code class="python keyword">=</code><code class="python plain">DEVICE):</code></div>
<div class="line number32 index31 alt1"><code class="python spaces">  </code><code class="python comments"># Register Addresses</code></div>
<div class="line number33 index32 alt2"><code class="python spaces">  </code><code class="python plain">REG_CALIB </code> <code class="python keyword">=</code> <code class="python value">0xAA</code></div>
<div class="line number34 index33 alt1"><code class="python spaces">  </code><code class="python plain">REG_MEAS  </code> <code class="python keyword">=</code> <code class="python value">0xF4</code></div>
<div class="line number35 index34 alt2"><code class="python spaces">  </code><code class="python plain">REG_MSB   </code> <code class="python keyword">=</code> <code class="python value">0xF6</code></div>
<div class="line number36 index35 alt1"><code class="python spaces">  </code><code class="python plain">REG_LSB   </code> <code class="python keyword">=</code> <code class="python value">0xF7</code></div>
<div class="line number37 index36 alt2"><code class="python spaces">  </code><code class="python comments"># Control Register Address</code></div>
<div class="line number38 index37 alt1"><code class="python spaces">  </code><code class="python plain">CRV_TEMP  </code> <code class="python keyword">=</code> <code class="python value">0x2E</code></div>
<div class="line number39 index38 alt2"><code class="python spaces">  </code><code class="python plain">CRV_PRES  </code> <code class="python keyword">=</code> <code class="python value">0x34</code></div>
<div class="line number40 index39 alt1"><code class="python spaces">  </code><code class="python comments"># Oversample setting</code></div>
<div class="line number41 index40 alt2"><code class="python spaces">  </code><code class="python plain">OVERSAMPLE</code> <code class="python keyword">=</code> <code class="python value">3</code>    <code class="python comments"># 0 - 3</code></div>
<div class="line number42 index41 alt1"><code class="python spaces">  </code></div>
<div class="line number43 index42 alt2"><code class="python spaces">  </code><code class="python comments"># Read calibration data</code></div>
<div class="line number44 index43 alt1"><code class="python spaces">  </code><code class="python comments"># Read calibration data from EEPROM</code></div>
<div class="line number45 index44 alt2"><code class="python spaces">  </code><code class="python plain">cal</code> <code class="python keyword">=</code> <code class="python plain">bus.read_i2c_block_data(addr, REG_CALIB,</code> <code class="python value">22</code><code class="python plain">)</code></div>
<div class="line number46 index45 alt1"></div>
<div class="line number47 index46 alt2"><code class="python spaces">  </code><code class="python comments"># Convert byte data to word values</code></div>
<div class="line number48 index47 alt1"><code class="python spaces">  </code><code class="python plain">AC1</code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">0</code><code class="python plain">)</code></div>
<div class="line number49 index48 alt2"><code class="python spaces">  </code><code class="python plain">AC2</code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">2</code><code class="python plain">)</code></div>
<div class="line number50 index49 alt1"><code class="python spaces">  </code><code class="python plain">AC3</code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">4</code><code class="python plain">)</code></div>
<div class="line number51 index50 alt2"><code class="python spaces">  </code><code class="python plain">AC4</code> <code class="python keyword">=</code> <code class="python plain">getUshort(cal,</code> <code class="python value">6</code><code class="python plain">)</code></div>
<div class="line number52 index51 alt1"><code class="python spaces">  </code><code class="python plain">AC5</code> <code class="python keyword">=</code> <code class="python plain">getUshort(cal,</code> <code class="python value">8</code><code class="python plain">)</code></div>
<div class="line number53 index52 alt2"><code class="python spaces">  </code><code class="python plain">AC6</code> <code class="python keyword">=</code> <code class="python plain">getUshort(cal,</code> <code class="python value">10</code><code class="python plain">)</code></div>
<div class="line number54 index53 alt1"><code class="python spaces">  </code><code class="python plain">B1 </code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">12</code><code class="python plain">)</code></div>
<div class="line number55 index54 alt2"><code class="python spaces">  </code><code class="python plain">B2 </code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">14</code><code class="python plain">)</code></div>
<div class="line number56 index55 alt1"><code class="python spaces">  </code><code class="python plain">MB </code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">16</code><code class="python plain">)</code></div>
<div class="line number57 index56 alt2"><code class="python spaces">  </code><code class="python plain">MC </code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">18</code><code class="python plain">)</code></div>
<div class="line number58 index57 alt1"><code class="python spaces">  </code><code class="python plain">MD </code> <code class="python keyword">=</code> <code class="python plain">getShort(cal,</code> <code class="python value">20</code><code class="python plain">)</code></div>
<div class="line number59 index58 alt2"></div>
<div class="line number60 index59 alt1"><code class="python spaces">  </code><code class="python comments"># Read temperature</code></div>
<div class="line number61 index60 alt2"><code class="python spaces">  </code><code class="python plain">bus.write_byte_data(addr, REG_MEAS, CRV_TEMP)</code></div>
<div class="line number62 index61 alt1"><code class="python spaces">  </code><code class="python plain">time.sleep(</code><code class="python value">0.005</code><code class="python plain">)</code></div>
<div class="line number63 index62 alt2"><code class="python spaces">  </code><code class="python plain">(msb, lsb)</code> <code class="python keyword">=</code> <code class="python plain">bus.read_i2c_block_data(addr, REG_MSB,</code> <code class="python value">2</code><code class="python plain">)</code></div>
<div class="line number64 index63 alt1"><code class="python spaces">  </code><code class="python plain">UT</code> <code class="python keyword">=</code> <code class="python plain">(msb <<</code> <code class="python value">8</code><code class="python plain">)</code> <code class="python keyword">+</code> <code class="python plain">lsb</code></div>
<div class="line number65 index64 alt2"></div>
<div class="line number66 index65 alt1"><code class="python spaces">  </code><code class="python comments"># Read pressure</code></div>
<div class="line number67 index66 alt2"><code class="python spaces">  </code><code class="python plain">bus.write_byte_data(addr, REG_MEAS, CRV_PRES</code> <code class="python keyword">+</code> <code class="python plain">(OVERSAMPLE <<</code> <code class="python value">6</code><code class="python plain">))</code></div>
<div class="line number68 index67 alt1"><code class="python spaces">  </code><code class="python plain">time.sleep(</code><code class="python value">0.04</code><code class="python plain">)</code></div>
<div class="line number69 index68 alt2"><code class="python spaces">  </code><code class="python plain">(msb, lsb, xsb)</code> <code class="python keyword">=</code> <code class="python plain">bus.read_i2c_block_data(addr, REG_MSB,</code> <code class="python value">3</code><code class="python plain">)</code></div>
<div class="line number70 index69 alt1"><code class="python spaces">  </code><code class="python plain">UP</code> <code class="python keyword">=</code> <code class="python plain">((msb <<</code> <code class="python value">16</code><code class="python plain">)</code> <code class="python keyword">+</code> <code class="python plain">(lsb <<</code> <code class="python value">8</code><code class="python plain">)</code> <code class="python keyword">+</code> <code class="python plain">xsb) >> (</code><code class="python value">8</code> <code class="python keyword">-</code> <code class="python plain">OVERSAMPLE)</code></div>
<div class="line number71 index70 alt2"></div>
<div class="line number72 index71 alt1"><code class="python spaces">  </code><code class="python comments"># Refine temperature</code></div>
<div class="line number73 index72 alt2"><code class="python spaces">  </code><code class="python plain">X1</code> <code class="python keyword">=</code> <code class="python plain">((UT</code> <code class="python keyword">-</code> <code class="python plain">AC6)</code> <code class="python keyword">*</code> <code class="python plain">AC5) >></code> <code class="python value">15</code></div>
<div class="line number74 index73 alt1"><code class="python spaces">  </code><code class="python plain">X2</code> <code class="python keyword">=</code> <code class="python plain">(MC <<</code> <code class="python value">11</code><code class="python plain">)</code> <code class="python keyword">/</code> <code class="python plain">(X1</code> <code class="python keyword">+</code> <code class="python plain">MD)</code></div>
<div class="line number75 index74 alt2"><code class="python spaces">  </code><code class="python plain">B5</code> <code class="python keyword">=</code> <code class="python plain">X1</code> <code class="python keyword">+</code> <code class="python plain">X2 temperature</code> <code class="python keyword">=</code> <code class="python plain">(B5</code> <code class="python keyword">+</code> <code class="python value">8</code><code class="python plain">) >></code> <code class="python value">4</code></div>
<div class="line number76 index75 alt1"></div>
<div class="line number77 index76 alt2"><code class="python spaces">  </code><code class="python comments"># Refine pressure</code></div>
<div class="line number78 index77 alt1"><code class="python spaces">  </code><code class="python plain">B6 </code> <code class="python keyword">=</code> <code class="python plain">B5</code> <code class="python keyword">-</code> <code class="python value">4000</code></div>
<div class="line number79 index78 alt2"><code class="python spaces">  </code><code class="python plain">B62</code> <code class="python keyword">=</code> <code class="python plain">B6</code> <code class="python keyword">*</code> <code class="python plain">B6 >></code> <code class="python value">12</code></div>
<div class="line number80 index79 alt1"><code class="python spaces">  </code><code class="python plain">X1 </code> <code class="python keyword">=</code> <code class="python plain">(B2</code> <code class="python keyword">*</code> <code class="python plain">B62) >></code> <code class="python value">11</code></div>
<div class="line number81 index80 alt2"><code class="python spaces">  </code><code class="python plain">X2 </code> <code class="python keyword">=</code> <code class="python plain">AC2</code> <code class="python keyword">*</code> <code class="python plain">B6 >></code> <code class="python value">11</code></div>
<div class="line number82 index81 alt1"><code class="python spaces">  </code><code class="python plain">X3 </code> <code class="python keyword">=</code> <code class="python plain">X1</code> <code class="python keyword">+</code> <code class="python plain">X2</code></div>
<div class="line number83 index82 alt2"><code class="python spaces">  </code><code class="python plain">B3 </code> <code class="python keyword">=</code> <code class="python plain">(((AC1</code> <code class="python keyword">*</code> <code class="python value">4</code> <code class="python keyword">+</code> <code class="python plain">X3) << OVERSAMPLE)</code> <code class="python keyword">+</code> <code class="python value">2</code><code class="python plain">) >></code> <code class="python value">2</code></div>
<div class="line number84 index83 alt1"></div>
<div class="line number85 index84 alt2"><code class="python spaces">  </code><code class="python plain">X1</code> <code class="python keyword">=</code> <code class="python plain">AC3</code> <code class="python keyword">*</code> <code class="python plain">B6 >></code> <code class="python value">13</code></div>
<div class="line number86 index85 alt1"><code class="python spaces">  </code><code class="python plain">X2</code> <code class="python keyword">=</code> <code class="python plain">(B1</code> <code class="python keyword">*</code> <code class="python plain">B62) >></code> <code class="python value">16</code></div>
<div class="line number87 index86 alt2"><code class="python spaces">  </code><code class="python plain">X3</code> <code class="python keyword">=</code> <code class="python plain">((X1</code> <code class="python keyword">+</code> <code class="python plain">X2)</code> <code class="python keyword">+</code> <code class="python value">2</code><code class="python plain">) >></code> <code class="python value">2</code></div>
<div class="line number88 index87 alt1"><code class="python spaces">  </code><code class="python plain">B4</code> <code class="python keyword">=</code> <code class="python plain">(AC4</code> <code class="python keyword">*</code> <code class="python plain">(X3</code> <code class="python keyword">+</code> <code class="python value">32768</code><code class="python plain">)) >></code> <code class="python value">15</code></div>
<div class="line number89 index88 alt2"><code class="python spaces">  </code><code class="python plain">B7</code> <code class="python keyword">=</code> <code class="python plain">(UP</code> <code class="python keyword">-</code> <code class="python plain">B3)</code> <code class="python keyword">*</code> <code class="python plain">(</code><code class="python value">50000</code> <code class="python plain">>> OVERSAMPLE)</code></div>
<div class="line number90 index89 alt1"></div>
<div class="line number91 index90 alt2"><code class="python spaces">  </code><code class="python plain">P</code> <code class="python keyword">=</code> <code class="python plain">(B7</code> <code class="python keyword">*</code> <code class="python value">2</code><code class="python plain">)</code> <code class="python keyword">/</code> <code class="python plain">B4</code></div>
<div class="line number92 index91 alt1"></div>
<div class="line number93 index92 alt2"><code class="python spaces">  </code><code class="python plain">X1</code> <code class="python keyword">=</code> <code class="python plain">(P >></code> <code class="python value">8</code><code class="python plain">)</code> <code class="python keyword">*</code> <code class="python plain">(P >></code> <code class="python value">8</code><code class="python plain">)</code></div>
<div class="line number94 index93 alt1"><code class="python spaces">  </code><code class="python plain">X1</code> <code class="python keyword">=</code> <code class="python plain">(X1</code> <code class="python keyword">*</code> <code class="python value">3038</code><code class="python plain">) >></code> <code class="python value">16</code></div>
<div class="line number95 index94 alt2"><code class="python spaces">  </code><code class="python plain">X2</code> <code class="python keyword">=</code> <code class="python plain">(</code><code class="python keyword">-</code><code class="python value">7357</code> <code class="python keyword">*</code> <code class="python plain">P) >></code> <code class="python value">16</code></div>
<div class="line number96 index95 alt1"><code class="python spaces">  </code><code class="python plain">pressure</code> <code class="python keyword">=</code> <code class="python plain">P</code> <code class="python keyword">+</code> <code class="python plain">((X1</code> <code class="python keyword">+</code> <code class="python plain">X2</code> <code class="python keyword">+</code> <code class="python value">3791</code><code class="python plain">) >></code> <code class="python value">4</code><code class="python plain">)</code></div>
<div class="line number97 index96 alt2"></div>
<div class="line number98 index97 alt1"><code class="python spaces">  </code><code class="python keyword">return</code> <code class="python plain">(temperature</code><code class="python keyword">/</code><code class="python value">10.0</code><code class="python plain">,pressure</code><code class="python keyword">/</code> <code class="python value">100.0</code><code class="python plain">)</code></div>
<div class="line number99 index98 alt2"></div>
<div class="line number100 index99 alt1"><code class="python keyword">def</code> <code class="python plain">main():</code></div>
<div class="line number101 index100 alt2"><code class="python spaces">    </code></div>
<div class="line number102 index101 alt1"><code class="python spaces">  </code><code class="python plain">(chip_id, chip_version)</code> <code class="python keyword">=</code> <code class="python plain">readBmp180Id()</code></div>
<div class="line number103 index102 alt2"><code class="python spaces">  </code><code class="python functions">print</code> <code class="python string">"Chip ID     :"</code><code class="python plain">, chip_id</code></div>
<div class="line number104 index103 alt1"><code class="python spaces">  </code><code class="python functions">print</code> <code class="python string">"Version     :"</code><code class="python plain">, chip_version</code></div>
<div class="line number105 index104 alt2"></div>
<div class="line number106 index105 alt1"><code class="python spaces">  </code><code class="python functions">print</code></div>
<div class="line number107 index106 alt2"><code class="python spaces">  </code></div>
<div class="line number108 index107 alt1"><code class="python spaces">  </code><code class="python plain">(temperature,pressure)</code><code class="python keyword">=</code><code class="python plain">readBmp180()</code></div>
<div class="line number109 index108 alt2"><code class="python spaces">  </code><code class="python functions">print</code> <code class="python string">"Temperature : "</code><code class="python plain">, temperature,</code> <code class="python string">"C"</code></div>
<div class="line number110 index109 alt1"><code class="python spaces">  </code><code class="python functions">print</code> <code class="python string">"Pressure    : "</code><code class="python plain">, pressure,</code> <code class="python string">"mbar"</code></div>
<div class="line number111 index110 alt2"><code class="python spaces">  </code></div>
<div class="line number112 index111 alt1"><code class="python keyword">if</code> <code class="python plain">__name__</code><code class="python keyword">=</code><code class="python keyword">=</code><code class="python string">"__main__"</code><code class="python plain">:</code></div>
<div class="line number113 index112 alt2"><code class="python spaces">   </code><code class="python plain">main()</code></div>
</div>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<p>It is recommended that you download this script directly to your Pi using the following command :</p>
<pre>
wget http://ift.tt/1KfFbXk
</pre>
<p>or use <a href="http://ift.tt/1KfFbXk">this link</a> in a browser.</p>
<p>In order to run it you can use the following command :</p>
<pre>
sudo python bmp180.py
</pre>
<p>The output looks something like this :</p>
<p><img alt="BMP180 Example Output" class="aligncenter size-full wp-image-4854 no-display appear" height="100" sizes="(max-width: 350px) 100vw, 350px" src="http://ift.tt/1I89jVb" srcset="http://ift.tt/1VK04RQ 300x, http://ift.tt/1I89jVb 350x" width="350" /></p>
<p>The module is available from eBay, <a class="easyazon-link" data-cart="n" data-cloak="n" data-keywords="BMP180 sensor" data-locale="UK" data-localize="y" data-localized="y" data-popups="y" data-tag="raspberrypispy-21" href="http://ift.tt/1MEIQOp" rel="nofollow" target="_blank">Amazon</a> and many other online electronics shops.</p>
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BMP180 I2C Digital Barometric Pressure Sensor

The BMP180 device is a digital barometric pressure sensor. This is available on a small module which provides access to the sensor via the I...

BMP180 I2C Digital Barometric Pressure Sensor

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