“Ever wanted to build a Weighing Scale with a touchscreen? Never thought of it? Well read on and try building one…
Do you know what a TFT touchscreen and a Load Cell are ?
If Yes skip to Step 1 else just start by reading the Intro.
Introduction:
What is a Load Cell ?
A load cell is a transducer that produces electrical signal when a force is applied on it and deforms it.There are different types of load cell: button type,canister type, beam type,S-type,etc.Here I have used the Beam Type.
The beam type has 4 strain gauges. When the object to be measured is kept on the load cell the force being sensed deforms the strain gauge. The strain gauge measures the deformation (strain) as a change in electrical resistance, which is a measure of the strain and hence the applied forces. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration.The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used.That is why we will be using the HX711 amplifier.
What is a TFT Touchscreen?
TFT screens, are a type of active matrix LCD display capable of displaying millions of high-contrast, clear and bright color pixels.The TFT technology works by controlling brightness in red, green and blue sub-pixels through transistors for each pixel on the screen.The pixels themselves do not produce light; instead, the screen uses a backlight for illumination.
Touch screens are a type of overlay placed on a display screen used to register touch interaction on the screen. Touch screens are not a type of display, but rather a component that can be added to an existing screen. Touch screens use two different methods to register touch interaction called “resistive” and “capacitive,” which refer to pressure and touch sensitivity respectively.The one we will be using is a resistive type.
TFT touch screens use both the TFT and touch screen technologies together to create a touch-based interface overlay on a thin, lightweight display.
Want to learn more just Google it :D”