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Invention is Not Enough


In 1983, as part of their Design Processes and Products technology course, the Open University produced a book called Bicycles: Invention and Innovation, by Robin Roy. I was one of five people who provided comments and advice to Robin during the drafting of the book. It was supported by a TV programme entitled Invention is Not Enough. This featured, among others, my old friends John Pinkerton and David Duffield, both sadly no longer with us. You can watch it here: And if you do, you will see that it starts with John Pinkerton explaining that, no matter how good your idea is, ‘invention is not enough’ for commercial success.

I am not a professional inventor but I have invented three things that bear out Pinky’s assertion:

The personal cassette stereo

The first Sony Walkman prototype was built in 1978 but I conceived the idea in my bedroom as a lodger in a council house in Wantage (20 Wasbrough Avenue, since you ask), sometime between autumn 1969 and summer 1970.

Back then, I and other students liked our rock music. The normal way of listening to it in the late 1960s was on a record player or, better yet, a hi-fi system. But there were two main problems: firstly, most students could not afford a hi-fi; secondly, hi-fi systems, and even record players, were bulky and difficult to transport. However, the advent of the compact audiocassette, created by Philips in 1962, was beginning to offer the prospect of decent sound quality combined with portability.

The cassette was a slow burner and took a long time to catch on. By 1969 cassettes were only beginning to compete with vinyl in terms of sound quality and availability. I had recently bought a Pye portable cassette recorder, which had a Philips chassis and was much smaller than earlier consumer portable tape machines. (It was about 4 inches wide, 7 inches long and 2 inches deep.) It only played in mono and didn’t have a standard headphone socket. But I knew from reading DIY electronics brochures (such as the popular Lasky’s catalogue) that small and cheap modular stereo pre-amplifiers were available. I also knew that upmarket cassette decks were appearing, which conformed to the German hi-fi standard. (There was no British Standard for hi-fi, so the German DIN standard was taken as a base reference.)

So, if I:

  • took a standard Philips portable cassette machine,
  • replaced the mono tape head with a stereo one from an upmarket tape deck,
  • ditched the built in loudspeaker,
  • inserted in the space thus made available a modular stereo pre-amplifier, and
  • added a stereo headphone socket,

I would have a portable unit that could play reasonable quality stereo via headphones. Voilà, I had invented the portable stereo cassette player, at least 8 years before Sony! OK, it was a bit chunkier but it would have done the job.

However, I was an almost penniless student, with no time or money to invest in such a project. So, nothing happened: invention was not enough.

I’m sure that many other people in that era came up with the same idea but, lacking the resources of a large Japanese electronics company, did nothing about it.

Low voltage DC wall sockets

These days, the electrical socket plates on your wall can include not only mains voltage alternating current sockets (230 volts at 50 hertz in the UK) but also USB sockets, providing 5 volts direct current. You will be aware that USB is increasingly the standard for low voltage appliances, whether they be digital cameras, portable computers, smart phones, tablets or whatever. Having USB sockets on the wall, all around your house, makes huge sense, eliminating the need for external chargers or, as our American cousins know them, ‘wall warts’.

Back around 1968, we students of architecture were given a project that required us to write an imaginative electrical specification. Even back in those days, I was getting fed up with external power supplies for transistorised equipment, such as portable tape recorders and transistor radios. So I proposed that we should have a low voltage direct current mains circuit throughout the house. This went down very well with the tutor who marked my paper. I had come up with a concept similar to what is now, many decades later, becoming a reality. But again, nothing happened: invention was not enough.

Privacy antenna for hearing aid induction loops

My third invention came much later, in the early 1990s. As an employee in a technical department within Barclays Bank (don’t shoot – I wasn’t a banker!), I had been instrumental in getting Barclays to agree to install at least one induction loop amplifier in each of its branches, for the benefit of hearing aid users. These transmitters use an antenna to transmit the audio signal (the cashier’s voice) direct to the customer’s hearing aid without a loudspeaker and the distortion caused by room acoustics.

I felt that these antennas could be made very much cheaper, more effective and less obtrusive if, instead of a surface-mounted coil, they were in the form of a thin metallic line printed onto the anti-bandit glazing during manufacture of the modular laminated glazing panels.

By a stroke of luck, another part of the bank wanted to test an innovation refinement process. To do this, they brought my department and the Pilkington glass company together. Two clever chaps at Pilkington, John Evason and Stephen Day, took up my idea and further refined it by running two of my printed antennas in anti-phase. (Meaning, in crude terms, that one pushed while the other pulled.) This was done in such a way that, when the customer stood at the counter, he or she got a very strong signal, as they were always closer to one or other of the antennas. But anyone else with a hearing aid, a little further away, received two equal and opposite signals that cancelled each other out. So no other hearing aid user in the bank could eavesdrop.

Pilkingtons patented the design on the joint behalf of themselves and Barclays. John Evason, Stephen Day and myself got the kudos of being named as the inventors. (European Patent 0594375 A2, Translucent article having induction loop antenna, published April 1994) You can access the patent here:

But as far as I know, nothing ever came of it. Yet again, the point was made: invention is not enough!

Tony Hadland







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