Kathy and I are set a particularly tricky challenge today: to find a way of transmitting a voice without using sound waves. We decide to use light instead, by making a light beam transmitter! The idea being that using some basic equipment you can encode (modulate) your voice onto a light beam, send it over a distance and pick up the beam and its voice message using some other equipment and turn it back into sound. And there you have a light beam communicator (very handy in space where there is plenty of light but no air for sound to travel through).

Kathy makes up a few transmitters – a tube with one end covered in aluminium foil. When you speak into the other end it vibrates the foil and modulates the light that happens to bounce of it. So if you reflect sunlight from the foil and talk into the tube you encode the sound of your voice onto the Sun light.

She makes up a batch of beautiful tubes and has a go at polishing the foil to get a better reflectance and therefore greater efficiency. We need to try a few different designs (tube dimensions, foil area size etc) to see which will work best.

I play around with making the detector – the light beam receiver. This uses the radios that we have been given as an amplifier but crucially we need a modified transistor to pick up the light in the first place. All transistor technology is sensitive to light which (apart from the mechanical advantage) is why the devices are encapsulated in plastic or contained in a tiny metal can. If we cut off the top of the can and use the transistor in a standard amplifier circuit, the small variations in the transistor's behaviour as the light shines on it will cause tiny additional currents to flow in the circuit. With amplification these currents are exact electrical copies of the sound. When these are fed to a loudspeaker it converts the electricity into the sound which you can hear!

I played around getting the transistors out of the radios and, in particular, looking for metal canned, instead of plastic, versions. Then the tops of the transistors were carefully filed off and wired up to a meter. By taking them outside into the bright desert sunshine you could easily see the change in conductivity across the transistor wires between when the device was shaded and then put into the sunshine. This was a very exciting and rewarding moment. Its this sort of moment where I can relax a bit because I know that the fundamentals are all okay. Even though we may have to work really hard to get it to work well, I now know at this point that it is possible and that’s a massive Rough Science moment !

I am often asked if I enjoy working on my own or in a group best. The answer is - both. When I am working in my workshop at home I am very happy to be on my own and work at my own pace, following up whatever idea comes along – I am completely happy. However I have worked in some very successful groups and have also enjoyed that enormously. The thing is, when you work on your own you have the enjoyment of the single-minded focus and absorption. When you work in a group you have the added dimension of other people’s energy and creativity. In all honesty much greater things are possible in a group than are possible while working on your own – the old saying ‘two heads are definitely better than one’ is true - but it is a different experience.

Working with Kathy is often a mixture of feelings. On the one hand she is a very fast thinker and sometimes this makes me feel a little stressed as I am not sure if I ‘feel’ I can keep up. I sometimes want to think really slowly, and it’s almost like I want to savour the ideas and that’s hard to do in a group. On the other hand its always fun to have her high energy and enthusiasm around and, of course, that other viewpoint that a good scientist might have.