How to amplify sensor range from 1-1.2v to 0-5v?

Other Hardware Sensors
1

Hi,

I have developed a custom sensor (anemometer) that outputs a voltage in the range between 1.0 and 1.2V.

I am currently using it together with an Arduino Uno with an external analogReference to 1.2V, thus I do gain a little bit of resolution in my low range sensor. However, I was wondering wether there are ways of amplifying such signal to a bigger range, thus gaining more resolution?

I know that it may be done with am Op Amp, but I am really unaware of how they work and which component would work for me. Does anyone have any hints on cheap components I could use to amplify this signal?

In the best case scenario, a small IC that could amplify the signal from 1.0-1.2v to a 0.0-5.0v.

Thank you!

2

You need specifically a rail-to-tail opamp that is fully rail-to-rail on the output. Using an inverting
amplifier configuration you can set the + input of the opamp to 1.16V using a 33k+10k voltage
divider from 5V, and use 200k and 10k resistors in the feedback network to the - input to set
a gain of -20.

1.0V -> 4.36V
1.1V -> 2.36V
1.2V -> 0.36V

If you google inverting opamp amplifier you'll find lots of circuits, usually having the +ve input
set to ground, but it can be any voltage point you like to set the offset voltage of the amp, as here
with 1.16V

3

Awesome! Thank you very much MarkT!

Would you have by any chance a suggestion to a specific inverting Op Amp that you had already worked with?

4

Would the LM321 do the job?

5

No, but MCP6002/6001 (8pin DIP) ir rail-to-rail (or TS912)

6

Thank you hugely Ny and MarktT!

I've bought the MCP6002, and used it in the way MarkT have described. Worked better than I expected!

Best,

7

..dont leave the unused inputs floating.. read the datasheet