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en:altimet [2018/12/30 14:22]
fluktuacia [Parameters]
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-====== Barometer and altimeter ALTIMET01A ====== 
  
-A digital barometric pressure sensor for precise measurements of altitude and temperature. 
-Sensor output is digital - either to SPI or I2C. It differs according to the type of fitted sensor. 
- 
-{{:cs:modules:altimet01a_big.jpg?300|}} 
- 
-[[http://www.mlab.cz/Modules/Sensors/ALTIMET01A/DOC/ALTIMET01A.cs.pdf|Original MLAB documentation]] 
- 
-===== Module construction ===== 
- 
-The module is designed to be screwed to the base. The screws can be broken off, so the PCB can be glued directly to a flat surface, decreasing the weight and space requirements. You can see an example of this solution in [[en:uav]] construction. 
- 
-==== Possible sensors ==== 
- 
-The module can be fitted with following sensor types: 
- 
-  * [[http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL115A|MPL115A1]] - SPI interface, power supply up to 5V. 
-  * MPL115A2 - I2C interface 
-  * [[http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL3115A2|MPL3115A2]] - I2C interface with vertical pressure resolution 30cm and maximal power supply 3.6 V. This IO does not have SHDN signal and therefore there has to be a jumper fitted to module.  
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-==== Communication with sensors ==== 
- 
-MLAB documentation contains examples of connections for microcontrolers [[en:arm]], [[en:pic16f87xtq44|PIC]] and [[en:atmegatq32|AVR]]. 
- 
-Furthermore, both types of sensors (with I²C or SPI interface) can be read directly from the computer using a Python library [[en:pymlab|pymlab]] and conversion modules [[en:usbi2c|USBI2C]] and [[en:i2cspi|I2CSPI]]. 
- 
-{{ :cs:modules:altimet_i2c_spi_link.jpg?direct&300 | An example of connecting the SPI module version to PC. }} 
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-===== Parameters ===== 
- 
-When measuring the parameters of MPL3115A2 during the [[en:abl|ABL01A]] project, we found out that the pressure measurements were functional at least up to 16 km (approximately 10kPa), a much better result than the parameter stated in the catalogue list. On the other hand, the internal pressure atmospheric model is only usable up to 10 km of altitude - in higher altitudes it experiences considerable inaccuracies.  
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-==== Module testing ==== 
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-The realisation of a testing system for MPL3115A2 sensor uses [[en:i2chub|I2CHUB02A]] module, that enables a testing of more sensors at once. Sensors are placed together in a vacuum bell with controlled pressure and the pressure measurements are (together with temperature measurements) read by [[en:i2c|I²C]] bus. At the same time, a pressure measured by a reference measuring device DPI 145 is read by the main computer. 
- 
-{{:cs:modules:altimet01a_testing.jpg?300|}}{{:cs:modules:altimet01a_test_board.jpg?direct&400 |}} 
- 
- 
-Reading the pressure via I2C bus, a following python code was used: [[https://github.com/MLAB-project/MLAB-I2c-modules|Externí odkaz]]  
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-==== Modul power supply ==== 
- 
-<WRAP warning round> 
-I2C module version has to be supplied by a stabilised voltage smaller than 3.6 V, otherwise it can be destroyed. 
- 
-</WRAP> 
- 
-===== Related sites ===== 
- 
-  * [[http://prezi.com/q40vh-gggjg7/poloautomaticky-merici-system-pro-kalibraci-vyskomeru/|A presentation of calibration system ]] 
en/altimet.txt · Last modified: 2018/12/30 14:24 (external edit)