Anybody who is well-mannered at cabinetmaking / metal working 10 points!? I am trying to build a measuring size that will fit...

I am trying to build a measuring size that will fit these requirements:

It should be able to weigh something

25cm x 25cm x 100cm or smaller number

2kg or less

I am still trying to amount out how I am going to build this. I am not experienced in building contraptions close to this. I do not have deeply of tools either. What sensitive of scale should I sort (balance,spring, magnetic, electronic) and near what?
I am trying to do an important project alone so I'm basically asking for a few helpful hints/ideas.
Answers:    Build a harmonize beam, you will obligation
1 board 2 inches sq 1 ft long
a 1 ft sq of plywood 3/4 inch thick,
1 sanctuary knife blade,
a 1"x2"x 2ft long,
a hack saw , some nail or screws
fastener or screw an end of the 2 inch sq board to the center of the plywood, beside the hack saw cut a slot in the top of the 2x2
1/2" wide ,incert the safety blade blade into this slot sharp edge up. mesure the 1"x2"x2' for middle of the board, [flat side]
attach a small picnic basket,pan,or something on respectively end, to hold a counterweight and what you will be weighing, find the go together point of the 1x2 and make a small mark across the board with the hack saw, your done
only just buy a letter mount and use that as your muse for how to build one for heavier items.