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lightwave

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Everything posted by lightwave

  1. I have seen this done before. It was purely experimental and temporary, but it worked. All data on disks was destroyed.
  2. I forgot to mention that the long pendulum when swinging stays in the same path as it was when originally set swinging. The earth, meanwhile, rotates under the pendulum. The pendulum appears to move in relation to the earth, while it is actually the earth which moves. In any case, the pendulum marks off an intersection of a circle with each swing. After one earth rotation the pendulum has intersected the entire circle. The longer the pendulum the greater is it's stability. I have no idea how to obtain accurate length measurements from pendulums but this has been done before. If anyone knows, please post here.
  3. Here's a good forum about electronics: http://www.edaboard.com/ Your dimensions are odd... what did you mean '2 cm x 5 cm x ... ?' There's LOADS of component suppliers out there. Try googling.
  4. Make a long pendulum with the coins and thread from your shirt. When swinging it marks off a 24 hour period very accurately. Use your thread and pencil to make a circle then mark off segments to represent hourly time in 24 segments each divided up into 60 portions. That way you can easily tell the passing of time to the minute. Observing the swings can tell you seconds. Your thread and pencil easily make a round circle. Divide it into halves, then quarters then etc. Your paper clip could serve as an anchor to the pendulum in the ceiling. At least you can note time passing. You still won't know the time unless you have access to a sighting of the sun. Calibration of the pendulum to midday is easy if you sight the sun's shadow and the standing pen can be used to mark minimum shadow etc. I assume the room has a ceiling so you can't see out. Was that a part of your idea? A working light fixture will be needed as otherwise it'd be total darkness. But that's an interesting idea to use the light as a source of timebase. It'd potentially mark the passing of time but there'd still be no opportunity from it for calibration. Ancient people used a pendulum to derive a measure of length that was very accurate. The so called 'megalithic yard' which was 86.66656 cm.
  5. The holes in the mainframe is a good idea. That will save a few grams of weight. Wing design will be crucial to flight time too as well as an efficient propeller. Have a look at the 'butterfly' at Plantraco's website. It's a 3.8 gram flyer with electric motor, battery, controller and reciever. You are making a glider, so the electricals are of no interest to you, but the plane's construction might be what you are looking for. Balsa is very strong for it's weight. You could make all the spars very thin indeed before they get too weak. Expect to make a dozen or more models.
  6. Amazing.. what a coincidence that I should go to your own explanation. I take it that you work directly in that area.
  7. I'm an electronics engineer and have experience in microprocessors and instrumentation. My approach to any task is first to define it. I like to examine the problem from every angle... kind of like surround it and attack... hahahaha Having established a start point and I know the end point I then know the path. I always examine that path to find any issues that might erupt and slow my progress. Once I have a definition I proceed to gather the tools (hardware, instruments, software, data). I write up every stage - what's that old saying "an engineer needs a screwdriver and a pen. The screwdriver to make the adjustment, the pen to record it". I try to estimate hours to completion and I always produce a deadline, needed or not. It's much smarter to work to deadlines - it drives your pace. On the topic of invention - I am a student of the history of invention. I love it. As an engineer I had to come up with novel ideas constantly, mostly to save time or money. I developed a system of inventing, it works really well. For your projects in engineering don't waste time repeating things that have been done, done, done. Just take what you need 'off the shelf' hardware designs or software code, it doesn't matter. If you are producing something entirely new, do a basic patent search to see what's out there before engaging your money and time. Train your mind to think about what is needed in a particular place. There are many 'tools' for this. See Triz, Game Theory. Good overviews here: http://en.wikipedia.org/wiki/Triz http://en.wikipedia.org/wiki/Game_theory I use other mental tools too, but there's two to start. Invention has it's rewards which can be massive, but the path to wealth through invention tends to be a long one. Product innovation (something like developing an iPod) is faster. Also, get with a group which has the knowledge you need. You'll learn heaps from their activities. Trading information is a real art - learn it.
  8. arkain is a dunce who comes into this forum to wind people up.
  9. You appear to have answered your own question. In any case a copy of the book should answer all your questions. I have seen that novice engineers do come up with unusual approaches to problems, but only have a success rate about equal or less to experienced engineers. Novelty does not guarantee success, it does guarantee experience through trying things that others say won't work. Really, the days of trial and error like Thomas Edison are over. Engineering means successful, useful design using modern tools. It doesn't mean try everything else that WON'T work first. Invention (in case you are wondering) is quite different and automatically seeks novelty.
  10. See the oufit MetalStorm. They made a launcher/machine gun which fires 1 million rounds per minute.
  11. Without a CAD knowledge you won't be able to produce a drawing of anything you are required to design or modify. As an engineer you'll be taught CAD and you'll need to acquire a powerful computer knowledge. If you want to move into aircraft maintenance then CAD will be far less important to you. Blueprints! I last saw one of those about 20 years ago.
  12. Wikipedia has a tidy explanation of what it is all about. Very impressive. I'd love to build one. http://en.wikipedia.org/wiki/Aqueous_Homogeneous_Reactor
  13. Is such a reactor practical as a source of energy either small or large say 20 watts up to hundreds of megawatts?
  14. Yep, old UPS's are a good source of inverter. Thanks EXTERNET for mentioning it. UPS: 110 Vac in, convert to 12 V dc to charge the batteries, convert from 12 Vdc to 110 Vac to supply the PC with power. Some PC emergency supplies do this (they are not UPS's): 110 Vac in. Convert to 12 Vdc to charge batteries. 110 Vac from the input is sent to the output to supply the PC with power. When the input 110 Vac stops, the batteries supply the power to the inverter to produce 110 Vac. It's usually the battery that fails in a UPS. They are high quality batteries. Remove them and run a direct connection out to the 12 volt source.
  15. I've just been doing a bit of research and it IS possible to use spread spectrum on acoustic transmissions. There are a few commercial products out there. Although they are not small and they are not cheap. A tethered ROV doesn't need an acoustic modem, all the comms are via it's cable of course. But modellers use a 27 MHz or 40 MHz Radio Control transmitter to connect to their subs. In fresh water the transmission, only about 500 mW, reaches about 2 metres under water for short distances.
  16. Global warming will be found to be a scam orchestrated by Greenpeace and other outfits who are seeking vast quantities of public and private money.
  17. Seeing the entire EM spectrum would be fun, but what if hearing the entire sound spectrum would be possible. Like infrasound and ultrasound?
  18. Inverters convert (usually) 12 volts to 110 Vac or 240 Vac. The method is to switch the 12 volt supply on and off constantly through the primary of a transformer so that the secondary recieves around 110 volts ac. It's efficient to use transistors to do the job of the switching. Older inverters used a relay to accomplish the switching. Older inverters used only copper and iron to accomplish the switching but were not efficient anyway. Nevertheless they did the job. Yes, you can use only copper and iron to make an inverter. But why?
  19. Did you expect anything else? A wealthy jewess marries dolphin. Dolphins are the new gods (of the environment). Isn't it appropriate that the wealthy marry them (dolphins) first. May I ask a question? What is foolish about it? And that is a sincere question.
  20. If your purpose is to make swords and other edged weapons then why not just buy a commercial forge for this. You'd really be wasting an awful lot of time in re-inventing the forge. It's been done, done, done. After you've bought your commercial forge then take a trip to Japan, they brought knife edge manufacture to it's limit 100 years ago. You won't get an apprenticeship with one of the sword makers (thousands are in that queue) but they might give you a weeks tuition for a cheap $2000. There's loads of edged weapons makers around the world. Most of them produce junk. The superior makers charge whatever they like for their swords/knives. Re-enactors used to make thier own armor but lots now are buying it. There's a giant market out there for armor, weapons, clothing. Some people even make thier own cannons for re-enactments.
  21. I think it would be impossible to use multiple channels. The conductor (the ocean) has multiple pathways and multiple delays so each packet of data would arrive at very odd times. There would be multiple requests to re-send data (as there is anyway) on a multiple number of channels. Acoustic spread spectrum has been examined from time to time, but never used (commercially) that I know of. Data rates are slow through water, but they get even worse when the vessel gets a long distance from the reciever. Whales can manage to be heard over distances of 2500 km. But they don't transmit packets of data - they sing their message using tones. Inherently their 'data rate' is very slow and despite the distances they can still understand each other but there's a massive 'computer' at each end of the whale's transmission path - their brains. Morse is a very reliable communications system, it's very slow, but is still today regarded as the most reliable system of electronic communication we've ever invented. It's reliable because the operators have a powerful 'computer' at each end. Speed requirements for data transmission underwater is very high. 300 bps is adequate for basic data about functions on the craft, but video requires MUCH higher speeds. Except I have a method where the data speed requirement is much lower. It's often said that the ocean is very noisy now (due to ships) and whales can't hear each other. In fact whales can still hear each other over vast distances due to the range of tonal sounds they make. I believe whales can hear infrasonically. They would hear every tidal wave and undersea earthquake probably as a great rumbling noise (?). Rain can be heard on the surface of the water for many kilometres. Vessels can be heard and even exactly identified for hundreds of km's. Every sub has a signature noise, which navies like to keep track of.
  22. If all you want is a little toy sub there's loads of them on the net from $25. I designed an AUV some time ago and I produced a means of getting real-time video back to the surface without cables. I will not disclose how I did this. If you just want to drop a box in the water which is tethered and sends video back to the surface that is easy to do. There's designs on the net to do this and all the components are readily available. When something is tethered, you don't need to pay much attention to the hydrodynamics of the vessel. It can be any shape. To make it go somewhere while hanging off a cable you'll need some thrusters. All you need to do is have an electronic means of turning them off and on as required. It's usual to use power FET transistors for that. Your tether cable will have video cable, control lines, stainless steel core and power cable. Although it's easy to design a controller, there's off-the-shelf items to do this which are very cheap and come from an unusual source. They can handle 25 amps easily and cost around $35. If it's tethered, you won't need any system of diving the vessel, just allow it to sink. You might have to apply lots of ballast to get it to sink. One of your problems is that the cable has a high mass and a tiny vessel can't tow it. So your field of radius might be small if your vessel is under- powered. The deeper the dive the more powerful the motor will need to be to get a reasonable field of radius. The cable might have a mass of 500 g per metre. A 100 metre cable may have a mass of 50 kg. You will have to have a poweful motor/motors to tow it around. Just guessing, but around 110 watts seems practical. 110 watts at 12 volts is 9 amps. You'll need a small car battery. For a 100 metre dive expect the mass of the vehicle to be around 100 kg. But if all you want to be is a 'bathtub warrior' then just spend your $25.
  23. An ROV is a tethered vehicle. You appear to want to build an AUV which is an Autonomous Underwater Vehicle - meaning that it is untethered and under it's own control. It's quite usual for AUV's to be always moving. After all if you want a vehicle to be stopped then just tether it. AUV's therefore always have propellers like conventional submarines. All AUV's have an air space surrounding the electronics. You cannot reliably surround electronics with oil, however electrically inert it is. In any case you need some bouyancy available and for that you will need an airspace. No AUV has no computers. They all have several computers. Usually one for navigation, one for control and one for the sensor package (instruments). You may also need one for communications. You can get video back from an AUV without a cable. Control is available to you through acoustic modems. The data rate only needs to be 300 bps for control functions, after all you aren't performing maneuvers at 100 knots. Typically an AUV will move at a speed of around 4 to 8 knots. It's not fast, but if you want faster you'll need to have many more batteries and a bigger hull. Mostly they use lithium-ion batteries, but there are still a few who use lead-acid cells. Both will tolerate pressures to 300 metres. Most of the research and industrial uses all occur in the top 100 metres of water. To dive deeper has no purpose really unless you want to follow seals around the place or examine deep ocean objects. The deeper you want to go the deeper your pockets will need to be. The pressure imposes huge costs on the hull building. A 1000 metre dive will mean a very sophisticated vessel which might cost $200,000 to build. Your biggest problem in building an AUV is the hull. The electronics is straight forward to do. Writing the software is a tough one. Navigation is a specially difficult problem as you'll need a 2 axis or 3 axis magnetometer and writing the software for that is not easy. The hydraulics (shifting water around) on board are not difficult but they do need to be 100% reliable. The electricals are relatively easy. For the best AUV's they have a notebook computer on the surface communicating with the vessel. You'll need software to run on the surface computer to enable monitoring and control. It's usual to want to know battery volts, speed of vessel, depth, location, heading, height, motor revs, interior pressure and sensor values. You can do all this at only 300 bps, it's not really that much data. Hydroplanes are always used to control depth. All you need for those is modest sized stepper motors. Most AUV's will have a maximum mission time of 2 hours but there's a few that will run for many more hours. Survivability is a problem. If your vessel sinks you'll need to be able to recover it from possibly a big depth. If it runs off on you it'll be lost for ever as it could be anywhere inside a 10 km radius circle - about 40 square km. It'd cost hundreds of thousands to recover it. The vessel needs 'fail-safe' systems. If something goes wrong it auto-surfaces and signals it's position, often with a GPS and an optical beacon. Recovery at night, before the tides get it, is a problem. Hope that answers some basic questions. If you have any more feel free to PM me.
  24. Pale skin women look a lot nicer. That's all there is to it. Every culture has this facet to their culture. Chinese, Koreans, Philipinos are the same. The most stunning looking women are probably the northern Europeans. Many Scandanavian women are just amazing in thier beauty. Russian women are very good looking too. They are largely descended from the Scandanavians. I saw Oprah Winfrey interview a famous Indian actress on tv and Oprah seemed quite upset that pale women in India are much preferred. "Why?" she bleated... The answer was written on Oprah's face.
  25. Is that all they left us? A map ! What were they doing all that time? Partying with all that Greek wine? Sheeesh.
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