The general public’s growing familiarity with touchscreen interaction, which has been driven by the spread of consumer electronics devices such as smartphones and tablet PCs, is leading to an expectation that other aspects of our everyday life should make use of similarly intuitive and easy-to-operate controls. In retail, touch-based human-machine (or human-computer) interfaces have become commonplace in POS systems, from cash registers to self-service terminals.

Now vending machine manufacturers and operators are beginning to recognize the attractiveness, flexibility and functionality that can be gained from touchscreen technology. Advances in performance and design are starting to have a major impact on how customers interact with these machines; and, when they are combined with complementary technologies — cameras, facial recognition software, inventory management systems, cashless payments, short-range communications (NFC or Bluetooth) and slick graphical user interfaces — the benefits are more compelling.

The first vending machines were all mechanical. Vender design then evolved from electromechanical control and dispensing to electronic control. The advent of modern electronics resulted in greater functionality, and recent technological advances have taken things still further. These include sophisticated payment mechanisms, some using radio frequency identification to eliminate the need to use cash and reduce the risk of theft. And Internet connectivity now can provide information on whether machines require restocking or service, thus lowering running costs.

It is, however, the integrating of touch interfaces that really could revolutionize the vending machine industry. Conventional machines, which basically rely on buttons, have limitations in the number of products that can be offered to customers. More advanced units sporting high-resolution touchscreen color displays permit users to browse through a much larger range of product options. New products can be added when required, or targeted products can be shown during specific periods of the day to suit the location’s market demographics (e.g. rush-hour commuters vs. kids on school lunch break) with special promotions offered. And out-of-stock products can be hidden from view.

This technology also allows customers to manipulate virtual images of products, play small games connected with the brand, or obtain details on the ingredients and number of calories they contain (nearly impossible in conventional machines, where this type of information is hidden from view on the rear of the product).

It’s easy to be seduced by technology. Touchscreens on vending machines must not overshadow the vender’s main purpose, which is to generate revenue through regular use. If a touchscreen interface fails in its task, either by turning off a repeat customer through its poor performance, or in the worst case, actually preventing any purchase because of an outright breakdown, the lost sales and damaged reputation to the operating company can be catastrophic. In vending, proven reliability should be paramount when considering a touchscreen for use in a new vending machine.

Engineers need to consider three key factors when looking to embed touch control into vending machines.

1. The specified touchscreen solution must be durable, as these pieces of equipment are designed for 24/7 public use. Furthermore, some venders may be deployed in a variety of environments, including outdoors, where they will be subjected to wind, moisture and extreme temperatures. As the machines may be located in lightly supervised areas, the chosen touchscreen should be resistant to deliberate harm from vandalism, in addition to accidental scratches from users’ watches and jewelry.

2. Touch-sensing technology employed should be capable of supporting both small and large displays. Small touchscreens are easier to retrofit to existing vending machines, making compliance with regulations easier and cheaper. Larger touch interfaces present marketers with the ability to broadcast eye-catching, dynamic advertising when the vender is not being used, so as to attract business from passersby.

3. The chosen touchscreen solution should ideally support customization, such as screen-printed borders and logos, holes and slots for card readers and bill validators, and even curved surfaces. All of these custom capabilities will contribute to making the vending machine stand out and attract use.

Many touch-sensing technologies now populate the market, but not all are suited for vending. The thin-front conductive surfaces of resistive and capacitive sensors are relatively fragile and prone to scratches over extended use, resulting in touchscreen failure. Optical-based touchscreens, such as infrared (IR) and camera systems, need exposed bezels to house the sensor elements, preventing flat-fronted designs; they also are susceptible to damage by users and the environment, ultimately leading to failure. A number of touch technologies also have tendencies for sensors to deteriorate or “drift” over time, requiring regular maintenance and recalibration.

Touchscreens based on projective capacitance (p-cap) possess a set of attributes favorable to their potential use in vending machines, as well as other public-use and self-service machines. With no drifting issues, they have the capability to deliver accurate and highly responsive touch operation, even through a protective overlay that isolates the screen from the external environment and so protects it from potential sources of damage. However, standard p-cap technology based on indium tin oxide (ITO) patterns is generally not scalable or robust enough to provide the impact resistance or large form factors that are increasingly desirable for this type of application. By contrast, the copper-based p-cap solutions developed by Zytronic have enabled touch sensors to be applied on much larger scales than was previously possible, and in ultra-robust formats. This has helped self-service equipment manufacturers across the globe to confidently and reliably deploy vending machines in a wide range of environments and eye-catching designs.

There are clearly several major benefits to implementing touchscreen technology into vending machines, both in commercial and operational terms. With the proliferation of touch-enabled devices in consumer electronics, users increasingly expect touch interactivity on displays, wherever they are deployed, and such interfaces enable bright, attractive graphics and support for a greater breadth of features and intuitive interaction. Provided that a suitable touch-sensing technology is specified, it is possible to install human-machine interfaces on vending machines that deliver the high levels of reliability needed for public use.

In addition, deployment of multi-touch functionality will, moving forward, result in the proliferation of units supporting control via complex gestures.