Other Touch Technologies

ShadowSense vs Capacitive Touch

Even if you have never heard of capacitive touch screens, you have been using them ever since you picked up your first smartphone or tablet.

Capacitive touch screens are made of single or multiple layers of material that are coated with a conductor such as Indium Tin Oxide. A protective cover seals the assembly off from the environment.

When another electrical conductor, like a bare fingertip or a stylus, touches the surface, an electric circuit is completed at that location. Sensors embedded in the glass then detect the location of the flow of current, which is then registered as a touch event.

This is different from the way that resistive touch technology works, where physical pressure is involved.

Capacitive touch technology can be divided into:

Surface Capacitive

This is a simpler form of capacitive touch screen, with only one side of the insulator coated with transparent conducting material and electrodes placed at the four corners of the screen. When a conductor touches the screen, different quantities of current will flow from the electrodes to the conductor. The location can be calculated based on the ratio of these currents.

Projected Capacitive

A projected capacitive touch (PCT) screen is a solid state device that has two types of electrodes, called X and Y electrodes, in separate layers running in mutually perpendicular directions. When the conductor touches the screen, the electrical field between the X and Y electrodes change and sensors can instantly pinpoint the location.

Pros of Capacitive Touch Screens

  • Can support multi touch gestures like flick, pinch and swipe
  • Are durable and robust; up to a point
  • Last longer because there are no moving parts
  • Are sensitive and even a light touch can register an input
  • Are highly responsive

The Baanto ShadowSense Advantage

If you have ever tried to use the touch screen of your phone when it is wet, or when wearing gloves, you will know the limitations of capacitive screens. Apart from being unable to perform in such situations, capacitive touch screens also have other issues.

Baanto ShadowSense touch screens are designed to overcome these issues.

Cons of Capacitive Touch Screens

ShadowSense Benefits

Might not be able to work with non conductors of electricity like gloved fingers Screens work with non conductors like gloved fingers or paintbrushes
Affected by high humidity, dust and viscous fluids as they interfere with conductivity Screens work even when covered with water, ketchup, grease or foreign objects like mud
Affected by “ghosting” due to build up of static electricity, causing the screen to lock up or malfunction The screen will not “ghost”
Are costly to fabricate because of two ITO screens, and do not scale economically Screens can scale up cost effectively to sizes of 267’’ without any compromise in performance
May be affected by electrical noise and susceptible to scratches Screens cannot be scratched, even by a coin or a credit card and is not affected by electrical interference
Will not work if the screen is cut or smashed as the ITO layer will be affected Touch function is independent of the glass and screen will keep on working even if it is broken

ShadowSense vs Resistive Touch

The next time you are using a touch screen ATM, simply touch the screen without applying any pressure. You will find that the machine will not accept any input.

Apply pressure on the screen and it will start working. This is resistive touch technology in action.

A resistive touch screen is made of two transparent layers of glass or plastic, each coated with a conducting layer of Indium Tin Oxide (ITO). The conducting sides face one another and are separated by an air gap.

When pressure is applied by the user, the top layer bends and touches the bottom layer. This causes a small amount of current to flow at the point where they connect. The location of the touch event can then be measured by the sensors.

Unlike most other types of touch screens (capacitive, infrared touch screen technology ) these screens have moving parts. Depending on how they are fabricated, these screens can be classified as:

Analog 4 wire resistive

In this variant, if the top sheet has electrodes for the vertical direction (Y), the bottom sheet will have electrodes for the horizontal direction (X). The top and bottom sheets measure each others’ voltages and based on that sensors can determine the location of the touch point.

Analog 5 wire resistive

In this variant, the voltage of the bottom sheet is measured by the top sheet, with electrodes placed at four corners of the bottom sheet. The top sheet does not have any electrodes.

Analog 8 wire resistive

These screens are similar to Analog 4 wire screens. The only difference is an extra set of electrodes, which automatically take care of alignment and recalibration issues that crop up in the 4 wire screens over long term use.

Pros of Resistive Touch Technology

  • Inexpensive to make
  • Can accept an input from anything, including pens, gloved fingers etc
  • Can be easily assembled from the component parts; screens and sensors
  • Can work in rain or in the presence of other fluids

The Baanto ShadowSense Advantage

Resistive touch screens have a number of issues which are addressed by ShadowSense touch screens.

Operates with gloves or wet hands
Durable & long lasting
4K touch resolution
Ambient light immunity
Object transparency detection
False touch rejection
Drivers required
Touch response time 10 ms and up under 10 ms
Clarity Great Great

ShadowSense vs Infrared Touch

To truly understand the ShadowSense advantage, it’s important to explore other touch technologies, how they work, and what they can do.

Infrared touch screens operate by calculating light-beam interruption, or “beam break”, to determine the location of touch events. This is a perimeter-based touch technology differing from Surface Acoustic Wave, in that infrared light beams are used and not ultrasonic waves.

How Does It Work?

Using LEDs and light sensors placed on the vertical and horizontal axis of a bezel, the Infrared system casts a grid of light across the screen. When an object touches the screen, it interrupts the light beams on the grid causing the light to be blocked from the sensor. This loss of light is used to determine the location of the touch. Since the LEDs and sensors make a grid, the touch results in an X and Y coordinate from the beam break. These coordinates then communicate with the display to react with the software on screen.

Feature Comparison

Operates with gloves or wet hands
Durable & long lasting
4K touch resolution
Ambient light immunity
Object transparency detection
False touch rejection
Drivers required
Touch response time 10 ms and up under 10 ms
Clarity Great Great

Limitations of Infrared Touch Screens

  • Can be accidentally activated due to high ambient light
  • Suffers from lower resolutions creating inaccurate touch points
  • Cannot distinguish between user input or foreign objects like mud or insects crawling on the screen
  • Response times are slow as the operation is CPU intensive

The ShadowSense Advantage

Infrared touch screens have several issues that can impact their performance. ShadowSense touch screens are similar to infrared touch screens as both use infrared light and both have sensors, but that is where the similarity ends. ShadowSense has significant advantages over conventional infrared touch technology. Curious? – discover the ShadowSense advantage.

ShadowSense vs Surface Acoustic Wave Touch

To truly understand the ShadowSense advantage, it’s important to explore other touch technologies, how they work, and what they can do.

Surface Wave Acoustic (SAW) technology operates by tracking sound waves above the human hearing range, also known as ultrasonic waves, to detect the location of touch points on the screen. This technology is perimeter-based, such as Infrared and Optical touch technology, but use sound instead of light for its calculations.

How does it work?

A SAW touch screen is made up of a glass sheet with three components: transmitting transducers, receiving transducers, and reflectors. The transmitting transducers produce ultrasonic waves that skim over the surface of the screen, get reflected and are captured by the receiving transducers.
When a soft matter like human skin, touches the screen, the surface acoustic waves are absorbed, and the receiving transducers do not register any input. Based on this lack of sound the sensors can calculate the location of the touch event.

Feature Comparison

Features Surface Wave Acoustic (SAW) ShadowSense™
EMI resistance
Durable & long lasting
4K touch resolution
Object transparency detection
Accurate multitouch
Touch response time 10 ms and up under 10 ms
Clarity Great Great

Limitation of SAW Touch Screens

  • Do not function with a pen or any other hard material
  • High multi-touch latency
  • Can malfunction when dirt, oil, or droplets stay on the screen
  • Perimeter can’t be sealed from the environment and so attracts buildup in bezel

The ShadowSense Advantage

Surface Acoustic Wave has several issues that can impact performance and universal deployment. ShadowSense has significant advantages over SAW touch technology. Curious? – discover the ShadowSense advantage.

Any Questions?

How do we compare?

Feature ShadowSense Capacitive Resistive Infrared Surface Acoustic Wave
Input Agnostic
Contaminant Resistant
EMI Interference Resistant
Cost Effective Scaling
Scratch Resistant
Light Immunity
Driverless Interface
Object Transparency Detection
High Clarity
High Responsiveness
High Accuracy

●= all
◐= some