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I am trying to use an external ADC with my UNO for very precise measurement of my signal. The ADC which I am using is ADS1115.

http://henrysbench.capnfatz.com/henrys-bench/arduino-voltage-measurements/arduino-ads1115-module-getting-started-tutorial/

This is the site which I am referring to.It says the default reference voltage of the PGA gives a resolution of 188microvolt per bit.It also indicates towards changing the reference voltage to 2.048, to still increase the resolution per bit.

Can you please guide me in how to achieve this 2.048V.

Update: https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiFpq3P89vNAhXJro8KHa6IC04QFggpMAI&url=https%3A%2F%2Fcdn-learn.adafruit.com%2Fdownloads%2Fpdf%2Fadafruit-4-channel-adc-breakouts.pdf&usg=AFQjCNGhdMw47MRlXolMiMoHdsTwKMwMow

It seems that by adjusting the gain (page number 16-17 of 18) we can achive it.

WHat I need to know now, is where should I put that piece of code

ads1115.setgain(...)

in void loop() or in void setup()

Thanks

Anupam

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Reference voltage inputs are usually high impedance requiring little current. So you can get by with simple circuits like a resistor and zener diode. Here is just one I happened across:

enter image description here

Do some research to find out more about this.

For your specific case, you should read the ADS1115 specification sheet. As this ADC chip has it's own built in voltage reference.

In the Arduino paradigm, tasks that are to be executed once at the beginning of a program are placed in the setup() method. Tasks which are to be executed repeatedly are placed in the loop() method. As setting the gain of the ADC appears to only be done once (consult the ADS1115 PDF linked to above), it appears to fall into the former category.

Added later...

I changed the circuit diagram after I realized it was a bad example for creating an Analog to Digital Converter voltage reference.

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setup() runs once at the beginning after the program is run. However, loop() runs continuously after that.

The setgain() instruction is needed once at the beginning, so it should be in setup() function.

good luck!

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