Actually, this is how I started the project. See for instance this one here (OpenScan in 2019 https://www.instagram.com/p/Bt6JtjEoEM7/ https://www.instagram.com

Actually, this is how I started the project. See for instance this one here (OpenScan in 2019 https://www.instagram.com/p/Bt6JtjEoEM7/ https://www.instagram.com/p/Bt6JtjEoEM7/) But I have found that smartphones give very inconsistent results (probably due to image"improving" algorithms...), see https://www.instagram.com/p/B1q1syMoHfG/ https://www.instagram.com/p/B1q1syMoHfG/ So I moved on to the raspberry pi + camera, which is much easier and better to control as you need very, very consistent images...