Exercising control via touch and thought

T hank largely to advances in information technology, humans can interact with machines by many means. Touch screen and speech interfaces are now commonplace, with serious research under way into systems able to respond to thought. However, one should not neglect other possibilities such as feet, when hands are otherwise occupied, and systems that can intelligently distinguish humans from machines, in the interests of providing protection. Stephen Furner, of BTexact Technologies, thinks that, ultimately, there may be people walking around with electrodes planted in the backs of their heads. In the meantime, however, the best thought activated system Eureka has seen is the Cyberlink headband made by Brain Actuated Technologies in Yellow Springs, Ohio. The headband incorporates three electrodes, which pick up tiny electrical signals produced by muscle movements. This approach has already been well proven in its use to control the artificial hand grippers and limbs made by Hugh Steeper at Roehampton, among others. In the case of the headband, the system responds to turning eyes to right or left, and to clenching the jaw. On a visit to the BTexact laboratories at Martlesham Heath, Eureka found that, with a little practice, it is possible to use the system to move an on-screen cursor in an XY plane sufficiently well to be able to beat the computer in a game of ‘Pong’ – at least at level 1. Furner says that the main market area for the headband at present is probably game playing. For its part, the maker stresses its potential for the disabled, and cites successes in stimulating the intellectual development of severely brain damaged children. Another approach, still the subject of much research but also with commercial products available, are the ‘touch and feel’ interfaces known as Haptics. A typical product, much studied at BT, is the SensAble Technologies PhanToM. This device, developed in Woburn, Massachusetts, uses three force motors and encoders and looks rather like an ‘Anglepoise’ lamp. Putting one’s finger in the thimble at the end of the arm and pushing it in various directions encounters force resistances. These vary according to whether the virtual object is supposed to be solid, or capable of being cut or moved around. Applications are seen in tele-operation and telepresence. Experiments have also been carried out in a joint study with the University of Hertfordshire’s Sensory Disabilities Research Unit, involving both sighted and blind participants. BT is interested in using such products to interface to systems over the telephone network. With concern growing about the personal safety of politicians and the extent of their workloads, Furner suggests such systems might even be able to offer a virtual handshake as opposed to a real one. The main barrier to their wider use, according to Furner, is neither perceived tackiness nor lack of bandwidth but computer system latency, because of the time required to process data and computer feedback force. The cost of the Phantom, at around £15,000, is a lot higher than for a Logitech ‘Wingman’ force feedback mouse or similar, but resolution is also a lot better. Look, no hands! One hands-free technique that requires no further research is that of using one’s feet Herga Electric, based in Bury St Edmunds, has for some time produced a range of footswitches. These include one developed for gynaecological chairs that has up to eight pedals. This allows the doctor to move the patient as required, while keeping both hands on the emerging baby. For medical use, all the switches are 24V and conform to standard IEC 601. A ground plane is incorporated between the 240V mains and the 24V supply and the transformer is shielded. The switches also have double springs to ensure continued operation if one spring fails, and are made both anaesthetic-proof and waterproof to IP42 or IP68 as required. For anything involving use of lasers, there are two switches connected so that one checks whether the other is working. Other medical applications include: operating theatres, treatment rooms, electromyography, and camera, patient platform and instrument control. Herga Electric managing director Richard Chatham says that sales of these products are increasing 11% per annum against a 6 to 8% per annum growth in the world-wide medical equipment market generally. The dental seat market alone amounts to 300,000 seats in Europe and 250,000 in the USA. Safety has no barriers Another market with expanding opportunities is providing enhanced machine safety in the light of increasingly rigorous European Union requirements. A technical leader in such matters has long been Erwin Sick, which has just brought out new products to stop production lines if humans attempt to follow workpieces along conveyors. The products are known as SMS (Safety Muting System) Entry/Exit packages. Anything moving along the conveyor is detected by a safety light curtain. However, if separate photoelectric muting sensors detect an object large enough to break beam paths between from two or more sensors, the object passing through the light curtain is assumed to be product, whereas if only one light beam is broken, it is assumed to be a human. The company has offered the facility in terms of discrete products for some time but has now developed a single package with all sensors mounted on two cross shaped frames. On one cross, the light curtain is mounted on the vertical section, with two or four muting photo-electric sensors on the cross arm. The opposing cross carries the corresponding light curtain array and reflectors to work with the photoelectric sensors. It is possible to work with only two sensors and reflectors, by turning them to produce two crossing beams. They should then be angled so that it is only possible to break both at once on the downstream side of the light curtain. However, for added safety and ease of setting up, the company recommends working with four sensors and reflectors placed opposite each other. (More information at www.brainfingers.com/cyberlink.htm, www.btexact.com/projects/multisensory/, www.sensable.com, www.herga.co.uk & www.sick.co.uk)