JPH's NESTA PORTFOLIO
Inventions and Experiments
Shake-a-gen - a brief period studying some of Leonard da Vinci's designs inspired me into thinking about water and wave power. At the same time I was thinking about a simple demonstration of electricity for my school / college workshops. This lead to an extremely simple little electrical generator which has become a major workshops at The Creative Science Centre - its a great way of teaching the fundamentals of electricity. This design was published in Physics Education.
Battery re-activator - standard AA alkaline batteries are used in many different types of equipment these days including walkmans, personal computers etc. These experiments were made to follow up some research papers that claimed normal disposable AA batteries could be re-charged (or more correctly - re-activated) a couple of times. My plan was to make a wall mounted drop-in centre so that people could slot in there AA over night and pick them up re-activated the next day. I did make a prototype (above) but the results were disapointing. I found that the charger tended to change the internal resistance of the battery in an odd way and that it was not a reliable way of getting 'more' from standard batteries.
Video monitor - a prototype tiny video monitor for use with CCD cameras and other video sources was designed so that I could learn about video signals. This has since been used in the making of the Hollywood Science (BBC2) series as well as in my lectures.
24V to 12V converter - I built this to see if I could get more useful power out batteries. In many applications the battery supplying power to a device is not used effectively because the electrical device turns itself off before the battery is exhausted (at a preset voltage). In other words their may be a considerable power left in the battery (albeit at a lower voltage) that is never used. I tried to overcome this by doubling up the voltage using two batteries and using a homemade converter to reduce the voltage. In this way I thought that a greater amount of the power could be used from each battery because they would each run down to a much lower voltage before the converter stopped supplying power.
Moon Clock MK1 - I wanted to make a prototype clock that would track the phase of the Moon. The first version used standard electronic components and a 16 LED display to show the Moons phase. The device had three circuit boards and needed 16 LED's, 6 ingegrated circuit chips, 26 resistors, 7 capacitors, 1 diode and a transistor. The Moon clock has been tracking the Moon for a couple of years now.
Moon Clock MK2 - this version uses new PIC technology. PIC's are a computer-on-a-chip that can be programmed and so have a wide range of functions. I used what I had learnt about the first Moon clock in this design. This project gave me a great challenge for my first attempts at learning and using this new technology. Because so much is done inside the PIC chip a lot of the component hardware can be replaced at the programming stage (programmed in the PIC assembly language). In contrast to the many components of Moon Clock MK1 the M2 has only 1 IC, 12 LED's, 2 resistors and three capacitors. This simple design has been submitted to a popular electronics magazine (EPE, spring 2004) as a begginers article.
DTMF controller - I wanted to be able to control a mains powered device from anywhere in the world using the standard telephone system. There is nothing new in this basic idea but I wanted to make up my own design to teach me about the various technologies involved (eg. high current control, DTMF (dual tone mixed frequency) tones on the line etc.).
X-antenna - This is a novel and simple quick to assemble portable antenna design which has a very wideband responce over the whole of the VHF and UHF bands. The antenna performs well for reception and transmission. It can be used as a portable antenna for amateur radio work or as a quickly errected emergency antenna for the emergency services. The design has been written up and submited for publication in Six News the Journal of the UK Six Meter Group.
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THE CREATIVE SCIENCE CENTRE
Dr Jonathan Hare, The University of Sussex
Brighton, East Sussex.
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