#10 Tutorial: Make the Arduino Analog Readings more precise

Here I show a trick to increase the precision of the arduino analog readings just with software. No additional hardware needed.

The coding used by me is on Github:

[andyj]

I know you posted this sometime ago, but I just wanted to thank you for doing so. Has significantly improved the accuracy of my Arduinos readings. Brilliant.

[francoisdastardly]

The man with the Swiss accent and super high quality videos !!

[MrRfaass]

Very nice video! To increase the resolution, you can add up multiple samples, as there is some uncorrelated noise on the A/D and input signal. To get a more stable measurement you can for example add 4 values and divide by two to get an extra bit. Experiment a bit as there is enough sample time for a reading on a display... averaging cancels out noise.

[Taran]

your videos #9 and #10 were extremely helpful: i am putting together my first data logger and the bits of information are good. i will probably apply the code for the keyboard and the OLED to the next project. :) . thank you!

[rodrigomourapereira]

Thank you so much! I'm using a soil moisture capacitive sensor. With your code, my calibration Has significantly improved.

[mbaksa]

Nice video. Just a tiny correction - in formula one should use 1024 instead of 1023. It's not the highest value that one should be multiplying, it's the number of values (resolution), and the number of 10-bit values is 1024. So the formula should be VCC=1.1*1024/measured result

[ejkitchen]

Great video! Also thanks for the code. Worked great!

[pjwlk]

You saved me my last little bit of hair. (Not much left to pull out...lol). The precision you have described here is just what I was looking for. Thanks!!!

[thevideoboy]

Hello Sir, brilliant yet simple way of correcting hardware issue with software. My two ways of correcting this issue were: 1) use a higher supply voltage (2 series Lipo) and a 7805 to power the sensitive projects or 2) use a 3.3v regulator to feed the Aref, which limits the input voltage on analog input pins. Now I have an option #3 (or #0)! Thank you !

[alphonsesynrem]

Dear sir, again a very good work on reading very precise voltage with fluctuating usb voltages. I had this problem as during testing my uno from the supply of my pc usb, the voltage fluctuats around 4.95 to 5.1 volts according to the pc cpu load etc. After uploading the sketch and when it's built outside the readings are all off. So again to plug to the pc and rewrite the values as per the external 7805 regulator. This video lesson will really help me. I will give it a try. Thank you so much again.

[leandrohugosobrino]

Nice explanation. The problem is that 1, 1v internal reference is not so precise. It actually varies between 1.0 and 1.2v

[bartdepauw]

Hello Andreas. Nice trick ! Would this also work (or even be needed) on the ESP32 (WROOM) ? Need to measure up to 85 volts and I'm wondering if I would use the build in ADC or an additional AD1115 module ( both with resitor divider). AD1115 is higher resolution ( 15b in place of 12b ) and has a build in voltage reference, but 0.02 Volt resolution is good enough

[ericgibbs]

The ADC of the Arduino is normally ratiometric, as in referenced to Vcc. You can switch to an internal fixed reference of about 1.1V instead. Most external ADCs have their own built-in fixed reference. Both have different use cases.2

[howardsway]

Thank you, a very useful and precise description, good job. Is there something special about the Leonardo in relation to excel ? or can you do the same with the Uno or Mega2560?

[rockabanane]

Thx!! I was already wondering why my PV Energy meter was not correct! Grüße aus München :D

[rahulanshan]

Sir, recently i'm facing a problem when i connect ACS712 20a current sensor to my node mcu 8266 microcontroller.The reading value is not accurate at some points.then i searched on the internet and find out that the current sensor is 5v module while the esp8266 is only giving 3.3v. so how do i fix this?

[effgee]

Great video, thanks Andreas.

In the video the equation is presented as 1.1*1023*1000 but in the code on github it is actually 1.1*1024*1000. Which is correct ? I assume 1023, since the ADC reading will max out at 1023, and dividing that by 1024 will not give exactly 1.1V

[Karl_Levine]

Andreas thank you.
You refer to some video "as seen on the previous AMPÈREMETER VIDEO", but you don't link it, and I can't find it, can I get a link please?

[erikvanderleer]

Does the ESP8266 have an internal reference voltage which would enable it to apply this method to the analog in readings too?

[brandonly]

I have gone from 3 volts to 5 volts with 98 percent accuracy. As long as you tie one of the ground ports of the Arduino to whatever you are measuring, its 98-99 percent accurate. Am i wrong in doing this?