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Everything posted by EdwardM

  1. Hi fotoobscura, interesting handle and even more so project. If I can throw my $0.02's worth in, my first thoughts are that a series of 4/5 LED's+resistor+battery could be put in per bubble and could have a lifetime of several weeks, but I think that at the ranges involved, the LED's will do little more that mark their own positions and not provide any sensible amount of illumination for the artwork. An alternative but more expensive solution would be to have a battery + inverter + small fluorescent light per bubble. The light output from fluorescents being much greater, could be greater s
  2. Hi scuba14c the warnings section (page 70) of the app-note I mentioned earlier gives at least a partial answer to your last post Best of Luck Ed
  3. Hi magatru Good site!, I may need to use it myself soon Best of Luck Ed
  4. Hi scuba14c apart from the HV switch, the inductor design is about the most important part of what you're trying to do, can I suggest you have a look at http://www.semiconductors.philips.com/acrobat_download/applicationnotes/AN96052_1.pdf and particularly the section on inductor design Best of Luck Ed
  5. Sorry scuba14c, I get errors when trying to open your JPG Ed
  6. Hi scuba14c can you describe L1 in more detail or post a photo? Ed
  7. Hi All MP, forgive me if I take you slightly out of context, but can't agree with the statement that the site should be considered a failure. I've looked at many community sites recently and this is the ONLY one which consistently has about 20 guests/members on-line at any given time. Look at the number of views on any topic, even the most obscure has 40 or more and the more popular topics running into thousands of views. Of course there are many people who are unwilling to post, either from a fear of looking ridiculous or from not feeling they have *enough* expertise to contribute.
  8. Hi Alun couldn't agree more, the loonies are taking over the asylum Ed
  9. Hi audioguru here in the UK we've recently had a law passed that only licensed electricians can work on many types of home electrics. In all the houses I've had over the years, the only wiring problems I've found are those caused by licensed electricians! AAAAArgh ::) Ed
  10. Hi MP and everyone I likewise don't see a problem with posting in the wrong area particularly as some projects take in many disciplines and it's often not immediately obvious which way a thread is likely to expand, really it's down to the moderator to organise as they see fit. It's not uncommon to see MOVED but you're always able to find where the thread has gone. I've posted in other forums on the net where I thought I had some knowledge/expertise and in one site in particular was almost immediately flamed. Possibly the 'not invented here syndrome' was operating so I've tended to stay cle
  11. Hi Aun The site mentions 40 something volts ac, being a uni site means there's probably some integral calculus going on ;D Just to add to what you've said, I've never had a bad shock (well 1, more later) and that's because I had a good teacher - he advised that I keep one hand in my pocket when doing anything where there was a possibility of high voltage being present. The only painful one was a bit odd: I'd spent some time trying to solve a power supply problem in a satellite receiver out in my garage workshop but left it as I had to move on to other things. Anyway, about a month late
  12. Hi Folks I just checked the Manchester University, Dept. of Chemistry site and they say: Voltages in excess of 50 V can be lethal Which confirms what I was taught many years ago when at Radio college. Ed
  13. Hi Ante too embarassing, thats my normal standard of construction. Next time I build one I'll try to remember to post! Ed
  14. Hi Abu there was an excellent article published in Elektor magazine in July 2004 entitled light sensor technology (measuring daylight using LED's). It is worth trying to get a copy, if only for the impedance converter circuit which has an input impedance in the teraohm region. Author was K.J.Thiesler and according to the mag the download number is 030435-12 and available from www.elektor-electronics.co.uk/dl/dl.htm Ed
  15. Hi zosh the emitter is the pin nearest to the metal tab sticking out from the body Ed
  16. Hi magatru from the sound of it, the replacement battery is probably faulty and is not charging fully even if the PDA says that it is charged. To answer your questions: 1. There are counterfeit goods around, I don't know. If you got the battery from a reputable source then it was probably OK 2. mAh is a measure of the capacity of a battery to deliver current for some length of time. In your case, 950mAh means that the battery should deliver 950mA for 1 hour or 95mA for 10 hours or 9.5mA for 100 hours. To measure the fully charged battery capacity you need to do two things, first you
  17. Hi http://service.semic.sanyo.co.jp/semi/ds_pdf_e/LA6541.pdf Ed
  18. Hi V8meathead Several EPROM's are sometimes used in a system, this is why you find the pins /E and /G, the / means that they are active low (confirmed also by the small circle) and are used to (/E) enable a particular chip so that it can be read from or whilst programming, can be written to. The /G is an output enable. Normally all EPROM's will have their /G pins connected to 0v and the /E pin enabled individually so that data from only one chip will be output onto a common databus. This means that for every EPROM in this system every Q0 is joined together and all Q1's etc., forming a datab
  19. Hi Kasamiko take a look at this Ed http://www.emcesd.com/1ghzprob.htm
  20. Hi V8meathead sounds like you've worked it out already Take a look here: http://xtronics.com/memory/how_EPROM-works.htm Ed
  21. Hi Muhammad Abu Bakar try this http://www.semiconductors.philips.com/acrobat_download/literature/9397/75014374_micro.pdf Best of Luck Ed
  22. Hi magatru The first question I have to ask is: are you sure that the replacement L- Ion battery is fully charged? as within reason 950mAH is the same no matter which battery technology you use. I've done a net search of PDA's and some specify that either L-Ion or L-Polymer can be used. If the substitute starts fully charged and only gives 1 hour of life, does an original battery give full or the same length of time? To measure mAH, you need to at least be able to measure current using a multimeter, ideally you should use a datalogger as the power consumed by the PDA will vary greatly duri
  23. Hi Xenobius I'm half-awake now - my usual state - but was thinking if you need to do more than a few coils, one way is to take a round plastic rod, taper the end of it and machine a spiral groove into the taper of the correct number of turns - its then easy? to produces lots of copies Best of Luck Ed I can't think why I said "groove", I meant to say flat. Also, if the wire is wound tightly, just realeasing the tension slightly should be enough to slip the spiral off the rod.
  24. Hi MP I'm aware of the differences between and advantages of mag pickup, if you check back the posts, what I've done is provide one possible solution to moeburns' original question and hopefully given food for thought. ? my problem? On your point about diffraction and vertical movement, it's a good one and the cmos/ccd sensor in conjunction with DSP could provide a solution by measuring the rate of change of shadowing since the sensor is a nice mixture of analogue and digital technology. Digital in terms of position and analogue in that an analogue voltage is produced in each bin. All
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