Yes, you can do that with any sensor. If you are using a library, such as:https://github.com/bogde/HX711the scale will be "zeroed out" (the correct term is "tared") when the program starts. That library also has a tare() function that you can call in your sketch if you want to tare the scale at any other time. If you aren't using a library, you can simply write your own tare code.The options I know of are:A load cell and a HX711 module.A force sensitive resistor (FSR).There are square FSRs around the dimensions you want. I'm not aware of load cells in the configuration you are looking for, but you could make your own by mounting a platform to a load cell.As for other sensors you might find, you definitely want to do some research to see how easy it will be to interface them with an Arduino.