High drive touch controllers unlock new options for games designers

Author : Ian Crosby | Sales & Marketing Director | Zytronic

01 March 2019

Shuffle Master i-Table
Shuffle Master i-Table

Appearance and UX go hand-in-hand in the design of good games, with developers constantly trying to improve both. Casinos and arcades are intense environments with lots of visual and audible stimuli, with games competing for attention. This article explains how new touch controllers are addressing this by enabling more exciting and more capable designs than ever before.

This article was originally featured in the March 2019 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.

These controllers offer a faster, more responsive interface and allow closer integration of new functions, such as contactless payments and wireless phone charging. It’s now even possible to combine tactile and projected capacitive touch controls in the same area, and make the touch sensor responsive to the pressure of touch (‘force sensing’). To further enhance the appearance of arcade machines, it allows inactive borders to be significantly reduced, slimming the form/factor and reducing the cabinet footprint.

Let’s look at a number of challenges faced by pay-to-play hardware designers, and demonstrate how the latest touch controllers provide new opportunities and solutions.

Integrating mechanical controls
While players love the flexibility and dynamism of touchscreen interfaces, they also still appreciate the tactility of physical controls – for example, having a ‘bash’ button to spin the virtual reel displayed. Innovative technology from Zytronic can now bring the two experiences completely together, fitting a multitude of tactile buttons or physical dials in and around the active area of the projected capacitive touchscreen. Integrating mechanical controls into the active touch area in this way blends tactile response with touch interactivity, and opens new design possibilities for casino, arcade and skill game developers.

At the heart of these improvements is the new Zytronic ZXY500 controller, based on a custom ASIC chip and designed specifically to work with Zytronic touch sensors. Since Zytronic has full control over both the projected capacitive sensor manufacturing process and the touch controller design, it has been able to adapt both to create these unique capabilities. Its highly flexible manufacturing processes allow the touch sensing electrodes to be plotted around the aperture into which the tactile controls are located. Custom firmware running on the new ZXY500 touch controller can then enable full touch functionality around the physical button. Zytronic touch sensors can accommodate a range of different mechanical controls, from a simple push button to place a bet, to a dial whose position is detected through the touch sensor.  

Another way of offering tactile feedback has also been introduced: ‘force sensing’ capability. Zytronic has developed further custom touch detection firmware for the ZXY500 that responds to the increased surface area of a fingertip when pressed more firmly onto the screen, and graduates its output accordingly. Software developers can then use the variable Z-axis coordinates from the controller to activate different functions depending on the applied pressure, such as issuing an audible message alerting the user to the option selected when the screen is touched lightly, and then confirming the choice when pressed harder. This feature can also improve playability for partially sighted users.

Shuffle Master i-Table_2
Shuffle Master i-Table_2

Contactless payments and phone charging
A further step forward is the opportunity to locate useful additional functionality, such as contactless payment, wireless phone charging and customer tracking close to the active area of the touchscreen, enabling a tight, integrated layout. The technologies used to implement these functions, such as RFID, NFC and Qi, generate signals that can interfere with the operation of conventional projected capacitive touchscreens, but the new controller has industry leading signal-to-noise ratios and sophisticated algorithms that change dynamically to reject electromagnetic interference in the operating environment. Zytronic has tested each of these technologies with the ZXY500 controller and demonstrated that they can be implemented very close to the active touch area, without impairing the performance of the touchscreen.

The key to improving sensitivity is the drive signal applied to the sensors’ transmit (Tx) array of electrodes by the touch controller. The level of this signal is a classic trade-off, a low voltage signal can be overwhelmed by electromagnetic interference (EMI) from the environment, while a high drive voltage can create interference in the sensor itself, which can potentially degrade performance. Most projected capacitive touchscreen manufacturers are forced to use a Tx signal with a DC current of between 20-30V, due to limitations in available ‘off-the-shelf’ touch control components and ASICs. However, Zytronic’s new ZXY500 range of controllers have been purpose designed to operate at an industry leading Tx drive voltage of up to 40V, enabling full multi-touch detection in extremely challenging self-service and public use applications.

The results of this innovation are dramatic. The higher drive voltages reduce the influence of noise on the data captured. A significant source of this noise is the proximity of the display itself. With all projected capacitive touchscreens, it is necessary to have a gap (air or resin filled) between the front of the display and the rear of the touch sensor, and the new ZXY500 controller now allows this gap to be substantially reduced, depending on the size and type of display selected. This not only allows the whole machine to become slimmer and more compact, it also reduces optical parallax between the display and the overlaying sensor, improving the user experience and perceived accuracy of touch.

Each Zytronic projected capacitive touch sensor is manufactured with a conductive matrix laminated within the rear surface of the screen. This matrix consists of an array of ultra-low resistance, microfine Copper electrodes, which at 10 micron diameter are practically invisible to the human eye on a powered display. These electrodes are connected to the remotely mounted touch controller, which applies a small charge to the sensing array. When a finger, conductive stylus or known object approaches the front surface of the sensor, a change in the charge applied to the conductive matrix is detected at the crossing points within the sensing array. This induced change is largest immediately beneath the touch points, and the touch controller’s firmware algorithms filters interference, calculates the applied touch positions and rapidly conveys this data to the host computer in a stream of X-Y positional co-ordinates.

Zytronic’s experienced team of engineers have designed all three elements of the touch solution to work optimally together: the sensor, the controller and its embedded firmware.

46 inch sensor-
46 inch sensor-

Touchscreen design
In addition to directly improving performance, this new generation of ZXY500 touch controllers, combined with Zytronic’s flexible projected capacitive manufacturing process, provides game designers with limitless opportunities to customise the appearance of the game, irrespective of quantity, optimising it for the application and helping to differentiate the overall hardware from competitive products.

The new controllers allow the border around the perimeter of the touch active areas of the screen to be substantially reduced – for example, a touch sensor designed for a 55” display can now be designed with sub 10mm borders, helping to reduce the user interface ‘footprint’ – useful, in applications where space is limited.

Zytronic has been able to achieve this border reduction through proprietary new touch detection algorithms in firmware which allow the transmit (Tx) and receive (Rx) electrodes in the sensor borders to be located far closer together, without creating interference or ‘cross-talk’.

The ZXY500 controllers also now make it possible to design ‘soft’ keys around the edge of the dynamic active area of the projected capacitive touchscreen. These fixed touch ‘buttons’ are managed by the same controller, and their function can be defined by the designer – for example, keys for dimming/increasing brightness or raising and lowering volume.

The new p-cap controllers support up to 80 simultaneous touches, enabling true multi-user interactivity and enhanced ‘palm’ rejection capability (in other words, detecting and ignoring anomalous touches, such as an arm resting on the screen.) The Zytronic proprietary ASIC within the ZXY500 controllers also increases the speed of touch detection, updating touch co-ordinates in just 1ms at the controller output – reducing touch latency by a third compared to the previous generation controllers, and improving the overall user experience.  They can also reliably detect touches through more than 8mm of overlaying toughened glass, providing a player interface that is both as durable and reliable as it is attractive.

System integration and communications
A key factor in the success of a user interface design is how easy it is to integrate the controller into the rest of the system. USB is an extremely popular interface, but there are some applications that require RS232, I 2 C or SPI interfaces, and the new touch controller also supports these communication protocols.

casino touch display
casino touch display

Size is also an important consideration, and the smallest projected capacitive controller in the new ZXY500 range has been significantly reduced in size to just 61 x 64mm to support Zytronic touch sensor sizes up to ~19”. The flexible printed circuits (FPC) connecting the touch sensors to the new controllers have also been reduced to just 120mm in length, further simplifying integration.

For applications where space is at a premium, the new controllers are also available as a ‘chip set’. Under special agreement, Zytronic will provide the ZXY500 design files to a customer, and just supply the core ASIC and ARM Cortex microprocessor (with Zytronic touch detection firmware pre-loaded). The client can then embed the touch controller onto an existing motherboard within their system, saving space, cost and integration time.

Finally, the new controllers have been designed to be HID (Human Interface Device) compliant and offer ‘plug-and-play’ operation with later Windows operating systems, also supporting Linux and Android builds capable of multi-touch input.

Casino and arcade floors are an environment that is continually evolving, and Zytronic has always used innovation and the latest technology to help pay-to-play game designers engage the player – and provide the most immersive possible experience. Arcade machine developers are always thinking of tomorrow’s player as well as today’s – and so are we.

Players want the hardware they’re sitting at to match the compelling game software they’re using. With hundreds of slot machines often installed on a large casino or arcade floor, competing for and holding players’ attention is absolutely critical. We believe these new controllers will help make games more immersive and exciting, crucially providing arcade machine manufacturers with an opportunity to differentiate their hardware and captivate players.

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