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AD Converter PCF8591 for Raspberry Pi: Difference between revisions
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AD Converter PCF8591 for Raspberry Pi (view source)
Revision as of 19:07, 16 September 2015
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Image2: Calibrating ADC with voltage divider using voltmeter | Image2: Calibrating ADC with voltage divider using voltmeter | ||
==How to calibrate it== | |||
Please use [http://www.daycounter.com/Calculators/Voltage-Divider-Calculator.phtml Voltage Divider Calculator] to get values of resistors you need. I strongly recommend you to replace one resistor with trimmer resistor to calibrate it to right value. | |||
For measuring voltage the best is to use [https://github.com/quick2wire/quick2wire-python-api quick2wire] api library combined it with my prepared example [https://github.com/koss822/misc/tree/master/ad_pcf8591 github.com/ko.../ad_pcf8591] file pcf8591read which has these options: | |||
<syntaxhighlight lang="python"> | |||
ref_voltage = 3.3 | |||
divider = 6 | |||
</syntaxhighlight> | |||
where ref_voltage is standard Raspberry Pi 3.3 voltage and divider is voltage divider you selected on calculator above (in my example it is 6) | |||