Nonlinear Letter Scale - 1g to Infinity

Nonlinear letter scale that can measure various weight.

• It has 1g resolution for light objects.
• It can measure relatively heavy objects as well. No overflow.
• Easy to assemble (it consists of 3 parts).
• Easy to calibrate.

Supplies

• Stainless wire (thickness : around 1.5mm)
• Some weights to calibrate

Step 1: Print Parts

Print parts with your 3D printer.

• Print with supplied posture.
• Support is not necessary.
• "scale.stl" is for two-layer print technique. To give different color to the texts, use "pause at height" function of Cura Slicer to change the material during print.
• "scale-1layer.stl" is single layer version, all texts and indices are just holes.

Step 2: Assemble

Assemble the printed parts.

• Use soldering iron to weld the pin to the scale.
• Make sure that the index rotates smoothly. Do not set the pin too tight.

Step 3: Zero Caribration

Calibrate zero of the scale.

• Attach hook using stainless wire.
• Add some weight to adjust the zero.
• It is better to calibrate zero without main weight for the better sensitivity.

Step 4: Non-zero Calibration

Using an object of known weight, calibrate non-zero point.

• Adjust the amount of main weight so that the scale shows correct weight of the payload.
• Amount of main weight does not affect to the previously calibrated zero point.
• Calibration with a single object is sufficient. All other weight can be measured correctly.

Theory

• Angle of rotation of the scale is calculated by the arctangent of the weight of payload, so it can map from 0g to infinity into 0 - 90 degrees.