Keyboards
May 2002 - Always the right choice! Rugged keyboards for demanding applications
Item no. 1870
KeyboardsintegratableMetalwith TrackballPanel Mounted
Description
| Author: Dipl.-Phys. Gert Breidenbach ist Geschäftsführer der GeBE Elektronik und Feinwerktechnik GmbH in Germering bei München. | |
| Rugged keyboards for demanding applications | |
| The author sees the need for robust keyboards primarily in three areas: trouble-free use in climatically harsh environments, use of keyboards in processes with high cleanliness requirements, and assured operability in publicly accessible vending machines. This necessitates partly identical, partly oppositely oriented design features that promote the applicability of the now highly developed technology in other applications as well. | |
| If you look in the brochures of well-known keyboard manufacturers and distributors today, you will find keyboards that are highlighted as particularly robust in addition to the standard. And of course, the question immediately arises in laymen's minds, why are they needed? Why does a keyboard have to be made of steel, for example? | |
| There are a number of reasons why keyboards have to be particularly robust. And accordingly, the special design and material properties are also required to adequately counter such adversity, depending on the focus. | |
| Protection against harsh environmental conditions | |
| First of all, there are the completely unsuspicious general ambient conditions, which can certainly be classified as harsh in some applications. For example, a ticket vending machine stands outdoors all year round and is exposed to wind, rain, snow and strong sunshine. The sensitive electronics behind the operating keys must be protected against external influences, but above all against moisture. A keyboard with IP65 protection is required here, which means dustproof and jet-proof. It must be possible for it to rain down on the keyboard. | |
| However, since people today not only want to touch the keys, but also move them as much as possible and also feel this movement (tactile feedback), a sealing problem naturally arises between the moving keycap and the case. In most designs, this is solved by a rubber membrane inserted between the key switches and the keycaps. Rainwater entering between the keycaps and the housing is intercepted by this closed membrane. This all sounds quite simple, but it is complicated nonetheless. These membranes should hinder the movements of the individual keys as little as possible, since the keys should be easy to strike. In addition, this membrane should be able to withstand all environmental conditions. The membrane and the key switch must not be damaged by frequent rough handling. This is achieved by installing a so-called mechanical baffle plate between the keycaps and the key switches, which absorbs the mechanical impact on the key without this force being transmitted to the membrane, the key switch or even the electronic circuit. The bounce plate has to function especially when the keyboard is brutally hit with a fist. | |
| Vandal-proof keyboards -- a modern issue | |
| This brings us to another topic, namely the often unpredictable aggression of some contemporaries. They often can't restrain themselves when looking at a keyboard and obviously have to use all their strength to emphatically communicate their sporadic mental inspirations to the machine. If input points are normally unattended, it happens again and again that users feel animated to test the "robustness" of the device. Also, it may well be that the machine equipped with a keypad arouses the user's displeasure. The coin acceptor simply does not want to accept the inserted money or the machine has miscalculated and not given the correct change. | |
| Then it is the same as with the vandals. Justified or unjustified - the concept of vandalism comes from them in any case, and today this plays a prominent role in the argumentation for the use of robust vandalism- or vandal-proof keyboards. Unfortunately, a considerable amount of effort must be expended today to protect devices not only against harsh environmental conditions, but also against vandalism. For this reason, ATMs are equipped with keyboards whose keys are flush with the surface. But unfortunately, these are not so easy to feel. | |
| Stainless steel keyboards with designer touch | |
| Over time, the use of metal deep-drawing techniques has led to the development of stainless steel keycaps, which allow the construction of well-designed yet robust stainless steel keyboards. With keystrokes of up to 3.5 mm, these keycaps can be operated almost as easily and quickly in the ten-finger system as normal long-stroke keyboards. This metal deep-drawing technology also allows the keycaps to be shaped in a designer way, so that today one encounters square, round, barrel and lenticular keycaps. This also prompts some enthusiasts to use the well-designed complete keyboards in stainless steel housings quite alienated from their intended purpose as a designer piece of jewelry for operating the desk PC. | |
| Custom layouts are more or less complex | |
| What all stainless steel keyboards have more or less in common is that the lettering is done by laser, so country-specific variants are generally easy to procure. Customized layouts in the key arrangement are more difficult. There are standard keyboards with the usual PC-compatible key arrangements, but if someone wants, for example, a more compact key arrangement or a few more keys on the keyboard (e.g. as function keys), the customer-specific arrangement is usually complex. Elaborate because besides the individual contact board, the mechanics of the housing, the baffle plate and the IP-65 seal have to be redesigned with tools. | |
| Therefore, even in this keyboard category, some devices offered as standard keyboards have emerged for the various use cases. If, for example, a monitor is to be operated that is controlled with mouse functions, stainless steel keyboards with built-in mouse replacement functions in the form of trackballs -- even trackballs with a stainless steel ball -- and -- somewhat less robust -- with a built-in touchpad are the right choice. Trackballs with two or three individual buttons are also available. These are used successfully as mouse replacement functions, for example, alongside number pads, which are used with up to 30 keys as front-mounted or rear-mounted variants in control panels on automatic machines and in machine control systems. | |
| High cleanliness requirements necessitate robust keyboards | |
| Another field of application for robust keyboards is wherever extreme attention must be paid to cleanliness. There must be no "dirt corners" here. Everything must be able to be cleaned in a sterile manner - if possible with a steam cleaner. Here, stainless steel keyboards with a completely closed surface or keyboards with a glass surface are in demand and in use. In places where there is not so much mechanical stress, completely sealed, foil-covered keyboards can also do the job. However, when the going gets rough - in some meat factories, machines are operated with a butcher's knife - a piezo keyboard with a stainless steel surface is often the last resort. In recent years, sensor technology has successfully developed further in this area, so that completely enclosed stainless steel keyboards are available for applications in food production, whose function is based on various piezo effects. In addition to the traditional sensors that work with piezo crystals, a Swiss company offers a relatively new process that exploits the piezo effect of strained plastic coatings. Since these coatings can also be applied to curved surfaces, this opens up completely new design possibilities for input systems. |
Technical data
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