Scale 45-110 mV signal to 0-3.3 V range

Thread Starter

Nasrin Shabani

Joined Aug 30, 2017
4
Hi,
I have a sensor that output signal values 45-110 mV. I need to translate these voltages to 0-3.3 V for my due arduino microprocessor. I understand that I can amplify the voltage using a non-inverting op-amp circuit to a range of 1.35-3.3 V, but is it possible to expand that range to 0-3.3 V?
 

bertus

Joined Apr 5, 2008
22,270
Hello,

When you subtract 45 mV from the input signal and then amplify by about 50 times, you will get the wanted range.

Bertus
 

ScottWang

Joined Aug 23, 2012
7,397
From 45-110 mV amplifying to 0~3.3V, if using the Vratio = 3.3V/0.11V = 30 then the smallest input voltage should be Vin = 30mV, so the input voltage is from 30~110mV amplifying to 0~3.3V, if the input voltage is from 45-110 mV then the output voltage will be as 1.35~3.3V and that is you can get from the ADC input of Arduino.
 

Reloadron

Joined Jan 15, 2015
7,501
I have a sensor that output signal values 45-110 mV. I need to translate these voltages to 0-3.3 V for my due arduino microprocessor.
Since you are working off a sensor you may want to think about using an instrumentation amplifier rather than the choices you mentioned.The INA121 is a FET-input, low power instrumentation amplifier offering excellent accuracy... would be one of many you can consider. One merit is getting your parts count down. Use a pot to set the gain and for example with a gain of 30 you would get 30 * .045 = 1.35 volts and 30 * .110 = 3.3 volts. Then take care of the offset in your code. This is along the same lines as Scott's post.

Ron
 
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