Newbie here, need help!! with Digital Weighing Scale w/o Amplifier

Hi :slight_smile:
I'm a newbie trying to do a project on a diy weighing scale. Underneath a square glass plane, I connected 4 load cell at each corner then connected to my arduino mega 2560 analog input. However, the examples that I've found online all used an amplifier. I want to do it without an amplifier so how should it be done?

STEPS:

  1. take in 2 inputs per load cell (total 4 load cell = 8 inputs)
  2. The difference of the 2 inputs of each cell
  3. if A0>A1 = Differemce 1 OR if A1>A0 = Difference 2
  4. Sum up the 4 differences
  5. Total difference multiply by the resolution to get kg/bit
  6. Finally display the total weight

Questions:

  1. How to read the analog input?
  2. How do I do the zero calibration? (Because there is a glass panel on it)
  3. Do i need to do A/D conversion myself? How?
  4. What is the calculation for reading value of the difference in relation to kg?
  5. Is there any string commands to display the words like " Total weight:" with the final value?

fx1901 compression load cell (25lb)

If the loadcell only produces millivolt outputs you will need an amplifier to increase that to a range that the Arduino ADC can read usefully - 0 to 1v if you use the internal voltage reference or 0 to 5v.

...R