Opamp To Be Used With Arduino for Current to Voltage Conversion

Hello,

I am working on an Arduino based Blood Glucose Meter. My sensor gives a current value proportional to the glucose concentration, which I need to send to the Arduino for processing. The current value is in the range of uA.
I'm aware that I'll have to convert this current value into a suitable voltage value for the Arduino, and based on my research an approach to do this is to use an opamp as a current to voltage converter.

Which opamp should I use for my application? I read that since the Arduino operates on 5V, I won't be able to use the LM741 since it operates from -15V to +15V.

Hi,
To get the resoluton you need for the 5V input, you will need low noise instrumentation amplifers

google low noise instrumentation amplifier

and

google low noise instrumentation amplifier design

Tom... :slight_smile:

TomGeorge:
Hi,
To get the resoluton you need for the 5V input, you will need low noise instrumentation amplifers

google low noise instrumentation amplifier

and

google low noise instrumentation amplifier design

Tom… :slight_smile:

Thank you, Tom. I’ll look into this.
I assume a low noise instrumentation amplifier won’t need an additional RC filter?
Also, is using an operational amplifier with an RC filter comparable to using a low noise instrumentation amplifier?

is using an operational amplifier with an RC filter comparable to using a low noise instrumentation amplifier?

No.
An instrumentation amplifier has common mode rejection something that a simple op amp with filter can’t do.

To convert a current into a voltage you need a transimpedance amplifier or just a resistor, but given the low currents I would go for the transimpedance amplifier.

Grumpy_Mike:
No.
An instrumentation amplifier has common mode rejection something that a simple op amp with filter can’t do.

To convert a current into a voltage you need a transimpedance amplifier or just a resistor, but given the low currents I would go for the transimpedance amplifier.

Thank you, Grumpy_Mike.
Which IC would you recommend for my application? I am expecting uA range currents that will be sent to the Arduino for computation.

Have a read of this https://www.digikey.co.uk/en/articles/techzone/2017/jun/how-to-design-stable-transimpedance-amplifiers-automotive-medical-systems

Thank you!