What sort and how big of a motor would be required to lift a 20kg speaker vertically into a roof space ?

I'm trying to make a platform to drop out from the roof at the press of a button to drop my home theater speakers out from the roof .

Question by cazz04   |  last reply



I wish to make vertical wind turbine for 6kW generator, any suggestions about wings for it ?

We are trying to make wind turbine, to pace it on the roof, could be few of them, but reasonably big, if you know what i mean. Thanks

Question by azdanovica   |  last reply


Has anyone ever mated flexible solar panels to vertical window blinds?

If you think about the amount of square footage that your average window or sliding glass door has, that's a LOT of potential space for solar panels! Are there any manufacturers that do this or has anyone here posted something about this?

Question by javajunkie1976   |  last reply


What would be a good material for creating a custom vertically oriented wind turbine blades?

For a school project my group an I are building a vertically oriented wind turbine  similar in orientation to the one in the link(http://www.youtube.com/watch?v=rLa_NY5U1nk) We would like to build a few different designs to test which will give us the best efficiency as we will do using it to generate maximum output voltage. I'm wondering, what would be a good way to create these different custom pieces, especially the curved airfoil shapes we may wish to utilize in the design? Thanks!

Question by ddrocketman   |  last reply


How would I choose the most efficient electric motor to use as a generator for a small wind turbine?

I have a school project to build a small wind turbine (approx. 8" propeller diameter) to produce the maximum out DC voltage possible.  We are still deciding between a horizontal & vertical orientation (leaning towards vertical) but we need some help on understanding what we should look for in the motor/gear setup in order to produce the maximum possible voltage at relatively low wind speeds.  What should I look for and where would be a good place to buy/scavenge these parts? Thanks!

Question by ddrocketman   |  last reply


Would bed pillows make good insulation for a roof?

I'm planning an earthbag house, and with its vertical walls, I need a roof. I'm going as cheap as possible, and I wondered if this would serve as a solution? I can get pillows from Walmart for about $5 a piece.

Question by jeniferchurch   |  last reply


Deriving the maximum range and angle of a projectile

In a thread in the Green group, AnarchistAsian and I were discussing his coil guns. I posed the question of what range he could get, and he asked me to go through the physics derivation. Here it is, simplified to require just algebra and trig.The kinetic energy of the projectile E = ½mv2, gives v = sqrt(2E/m) as the speed at launch. Let θ be the angle at which you launch (θ=0° is horizontal, θ=90° is straight up). Then you can decompose the speed into two components: vh = v cos(θ) is the horizontal speed,vv = v sin(θ) is the vertical speed.Gravity only pulls vertically, so the projectile's vertical speed will be slowed down until it reaches its maximum altitude, then it will fall back until it hits the ground. The horizontal speed will remain constant until it hits the ground and stops. To figure out the range, you need to know the time t that the projectile flies before it hits the ground; then the range is just R = vhtEnergy conservation guarantees that it's downward speed at the end is equal to its original upward speed, just with a change of sign. That also means that the total flight time of the projectile will be half going up and half going down. Once you determine how long it takes to reach the top of its flight, you're done; just double that answer :-)In the vertical direction, the maximum heightH = vvt - ½gt2(you need calculus to derive this result). From energy conservation, the initial kinetic energy in the vertical direction, Ev = ½mvv2 must equal the potential energy at the top of the flight, Pv = mgH:mgH = ½mvv2H = ½vv2/gSubstitute this on the left hand side of the trajectory expression,½vv2/g = vvt - ½gt2vv2 = 2gvvt - g2t2vv2 - 2gvvt + g2t2 = 0(vv - gt)2 = 0vv = gtSo, t = vv/g = v sin(θ)/g is the time to reach maximum height. Double that as discussed above, and you get the range R = 2 sin(θ) cos(θ) v/g.Work out the angle that gets you maximum range by just plugging in different angle values and finding the one that is biggest.

Topic by kelseymh   |  last reply


That didn't just happen, did my oscilloscope die!?!? How??? Repairable????

I went to my workbench today to discover that my BK Precision 30MHz analog scope has stopped working. Symptoms: ❶  Still shows a trace ❷  The trace does draw across the screen*  ❸  The horizontal time base seems to work ❹  10x horizontal magnification seems to work ❻  XY mode only draws in the X direction ❼  Waveforms do not show up, for either chA or chB ❽  Triggering seems to work (it causes the trace to draw more/less frequently. No vertical deflection)  ❾   Vertical controls for both channels have stopped working ❿   Dual trace shows only one trace ⓫   I have not been able to do anything to make the trace move up and down, vertical deflection is definitely shot. ⓬   * When changing the timebase, I noticed that the length of the trace horizontally gets shorter, and when a signal is present, or the vertical position for the appropriate channel is twiddled, it becomes the right length, within certain ranges. ⓭    When I was reaching for a powerstrip to turn off power to the lab the previous night, I heard a loud buzz, similar to that of the degaussing on a old computer monitor, but louder. no sparks or anything were visible as I recall. scared the crap outta-me, and I could not figure out what had happened. First thought was that maybe somewhere there was a live mains exposed somewhere that had shorted to ground or neutral. That was quickly dismissed since nothing was exposed like that, and also it would have popped the circuit breaker, and instead would have sounded like a firecracker. This sounded more like a small transformer failing. Also the same day, I have been messing with a tesla coil circuit (my beefed up slayer exciter) and the probes were sitting here by not connected picking up interference. They were in 10X mode, I do not remember the volts per division, however. I do recall a trace being shown on the display the previous day. With these symptoms, I think the issue has to do with the vertical control on the CRT, and perhaps another, separate issue with the horizontal time base control, or possibly triggering. I think I might do a teardown on it to see if there is anything obvious that has failed, such as a charred coil. Then I will need to figure out what had caused the issue. It is obviously something gone horribly, horribly wrong with vertical deflection or something of the like. I will have a look at the schematic and see what I can learn about the operation of the scope. I am glad I do have the user manual and schematics, so it should be straightforward, it is a nearly 100% BJT design. The scope was used and old, and lacked a lot of features, such as cursors and frequincy counters. Perhaps it is time for a digital upgrade anyway... http://www.amazon.com/gp/product/B00N222I6C/ref=s9_simh_gw_p504_d15_i1?pf_rd_m=ATVPDKIKX0DER&pf;_rd_s=desktop-1&pf;_rd_r=1VEC8M45MB2T9REXCR7N&pf;_rd_t=36701&pf;_rd_p=2079475242&pf;_rd_i=desktop

Question by -max-   |  last reply


Longboard Wall Mount?

Right, I need some help... My bedroom is really small so I want a way of having my longboard mounted on the wall to save on some floor space, the only issue is that I need a way of having it hanging vertically on the wall but i would like it so I can see the paint job on the bottom of it and so the wheels don't marl my wall. Any ideas or suggestions? thanks

Topic by TJParmenter   |  last reply


Magnetic Rotor

http://youtu.be/zqG-TL0WnjE How does this device work? Has it ever been on instructables or anything like it? How would I go about mounting the magnets on the rotor? What sort of spring would I need for the magnet mounted to the vertical shaft that slides up and down? In short I want to know every little detail about building it before I begin so I don't go buying a lot of unecessary stuff and waste money.

Topic by merlin280   |  last reply


Single Piston Air engine

Hi all, need help/ advice in designing a single piston air engine, It is part of a mechanical engineering course I am currently studying, the only parameters i was given are - Single cylinder with vertically displaced piston with rotation of the input shaft on a horizontal axis - free standing with an operating envelope of 300mm x 300mm x 300mm - accommodate a nominal piston diameter of 20mm - engine capacity of 6.0cc / 6000mm (cubed) Any help would be greatly appreciated Thanks in advance

Topic by DavidO242   |  last reply


ceder cladding to timber frame extension, how to fix without it been seen ?

I would appreciate any help we are doing a wrap around ceder clad extension onto a timber frame. The architects have spec'ed 2x1 cedar vertically and then 2x2 cedar alternate throughout. so you get the pattern 2x1 2x2 2x1 2x2. also for shrinkage and expansion what would you guys advise gap between each piece. all help much appreciated.

Question by JamesS2   |  last reply


Curious striations on avocado sapling trunk...?

Greetings I started growing an avocado tree from a pit...it's at least 8 months old now.  My roommate said it was important to nip off some of the top shoots so that it would get stronger lower leaves.  After it got about 20 inches tall, we nipped off the top, and now a few weeks later the top half of the trunk is showing signs of what I can only assume is infection. The bottom of the stalk/trunk is quite strong and stiff - as are the 6 or so leaves coming from it.  Above that, where the newer leaves are, the stalk is mottled with 2-5mm long dark spots running vertically, and all the leaves in the area with the spots are paper thin, slightly translucent, and very weak.  On top of them they have a waxy shiny sheen, where the healthy leaves do not.  The healthy leaves are quite erect sideways, opaque, and vibrant dark green -  while the weaker leaves droop almost vertical, are translucent, and lighter in colour. Is it an infection?  Is there anything I need to worry about?  Is there anything I can actually do? Pictures:  1) Good bottom 1/3 section 2) mottled middle 1/3 section 3) mottled top 1/3 section

Question by frollard   |  last reply


Best way to convert motor power to wheel power? Answered

I have a dolly cart and motor, and I want to motor to move the dolly cart as slowly as possible (It's already four RPM, but just take that into account in the method you recommend). I need one of the inner/vertical wheels to be spun by the motor. Both the cart and the motor are pictured below. I am using this for time-lapses, so it should be as consistent as possible. What is the best way to connect the two parts so the motor spins one of the wheels?

Question by sblaptopman   |  last reply


How does a spindle sander oscillate? Answered

I'm wanting to cobble together a spindle sander using the guts of a hand drill. Mounting it is pretty trivial, but it would be very cool if I could make it oscillate vertically as well. Unfortunately, I don't have a spindle sander to take apart so I can see how it operates. Can anyone tell me what mechanism moves the spindle up and down? Does it use the same motor that rotates the spindle, or is there a secondary actuator involved?

Question by yoyology   |  last reply


Ever seen a rotary tool that used a large flywheel?

Has anyone ever seen or built any kind of rotary tool that was driven by the inertia of a large, heavy flywheel? I have seen kick wheels for pottery, but i am curious about a vertical flywheel. Lathe, Grinder, pump.... Seems like you could attach a treadle to a pedal assebly of an old bicycle to drive the flywheel....if the pedal assembly was the free wheeling kind, and there was something pulling the treadle back up, it would only power the flywheel when the treadle was pushed down.

Question by ClandestineIntestine   |  last reply


Wall mount a non-VESA monitor?

I have an ASUS ML248H 24" monitor that I want to mount to higher to remove the footprint from my desk and to have a better viewing angle since I usually lean back so I have to look "down," compared to my body position, to look at it at the level of the desk. The problem is that it doesn't have any place to attach an off the shelf wall mount. The only place to attach anything to it is where the base/stand is connected, and it's a funny thing that would be really difficult to replicate (see picture) I've looked through many of the ibles in the subject and nothing seems quite right so any suggestions would be great. The only thing I can think of so far is to use the vertical part of the original stand which would add a couple inches to the depth and act like a lever, multiplying the weight on any thing holding up the monitor, but adds more options for attaching stuff in the form of one vertically oriented bolt hole at the opposite end of the one that attaches the bracket to the monitor, as well as four smaller holes at roughly 30  degrees to horizontal (see pic #2) I was thinking of something like a pipe coming up off the desk or out of the wall but can't figure out how to connect the two pieces so that I can still have swivel and tilt adjustment.

Question by siamonsez   |  last reply


Need advice...

I have a pvc bar made from 1 1/2" pvc schedule 40. the longest vertical pieces are 18" or less...I have a fishtank on it a 1/4 full and having 2nd thoughts.. Any guesses,estimates,educated insight on whether this will hold 0hh 450-475lbs ie 50gallon tank minimal gravel and deco plus fish lights etc...I'm still elaning towards I think so but i have a lot of electronics in the same room right now i dont need soaked.... And obviously I'm not holding anyone accountable for their opinion...

Question by needadvice 


Briggs & Stratton Lawnmower/Go Cart Engine to Power a Boat

I've heard of people mounting small (5 hp or so) Briggs engines in boats to power them. I have a couple of warn out 2-stroke outboards, but they are smelly, smoky, and unreliable. Does anyone know the best way to mount a Briggs (or Tecumseh, Robin, etc) as an inboard? I know there'd have to be shafts and seals, but I'm kind of looking for ideas before I start cutting on the old flatbottom. I have a couple of vertical shaft motors, and one good horizontal.

Topic by skunkbait   |  last reply


A mechanism that moves in the opposite direction of the applied force?

I am building a camera rig, and I would like to be able to accomplish very fluid movements with it. I have seen all kinds of existing camera rigs, but they all seem relatively static in one way or another. Simple bi-directional movement is alright, but something capable of vertical, horizontal and rotational movement would be preferable. If you push downwards, the camera moves upwards - that kind of thing. Even a material that is semi-flexible would work, as a rod to attach the camera to that would provide some sort of resistance, and a position to snap back to. I'm not looking for the whole design, just a starting point if anyone has any ideas about something that already exists that sounds like what I'm saying.

Question by epizeuxis   |  last reply


Redirecting a mechanical force? Answered

Hi, im looking for some help with a physics/engineering type problem. Im looking for the most effective method of tranfering a mechanical force from one direction to another. For example if i had a 1" horizontal rod struck on its east face which then begins to travel westward on a fixed horizontal track, im looking for a method of transfering the energy (not sure if thats the right word) in the opposite direction. A few important factors are that the rod which is struck does need to travel around 4 inches on the fixed rail, and any vertical movement needs to be kept to a minimum. Below is one of my early ideas, serves little pupose as the mechinism is too large but gives you the jist of what im talking about.

Question by Squibo   |  last reply


Wooden Air Cooled Water Chiller?

Does anyone have or know where to find plans for larger sized air cooled water chillers, such as those that used to be next to ice plants.  The vertical towers had water dropping through wooden, slanted slats which created chaotic air flow through the water, removing heat and chilling the return water.  Essentially speaking, I want to build a tower that can be used to chill large aquaria within outbuildings where fingerling trout are being raised. In doing web searches all I am finding are the heavy duty industrial chillers that are high energy users, expensive, and would not work with solar driven small water pumps. Thank you for any help, discussion or steer to websites. Bill

Question by BillClewis2   |  last reply


Re-design messenger bag strap so that it doesn't slide or bunch at the loop

Hi all, I have a Clive messenger bag that is perfect for my carrying and commuting needs, except for the strap. The material of the strap is pretty flimsy, not the tough woven type as found on timbuk2 or Chrome messenger bags. If the bag is too heavy (with books, etc) the strap slides so that it's too long. The strap is sewn into the bag on one side, and on the other side, the strap goes through a small (maybe 5 mm diameter) metal rectangular loop. The strap always bunches and the loop hangs vertically so that the tab connected to the bag and the bag strap are all bunched. Does anyone have any ideas on how to re-sew or replace the strap and/or loop so that the strap doesn't bunch or slide? Thanks

Question by    |  last reply


My chemistry textbook was right all along!

As reported in Physics World today, a team of Swiss and Dutch physicists have developed a novel tip for an atomic force microscope (AFM) using a single carbon monoxide molecule. The tip is stable enough to image individual atoms and bonds within molecules.The first image below is from the group's AFM of a single pentacene (C22H14) molecule on a copper (Cu(111)) substrate. The second picture shows the conventional chemical structure diagram (the vertices are carbon, and one hydrogen hangs off of each exterior corner), and the third is a "ball" model, with carbon atoms in black and hydrogen in white. As discussed in the article, the whole molecule is just 1.4 nm long, with a spacing of 0.14 nm between adjacent carbon atoms.The paper is out in today's Science, but it's pay-per-view.

Topic by kelseymh   |  last reply


Soldering Copper Round Bar

I plan on making a backdrop (pictured) out of copper. I have a little bit of experience soldering copper pipe. I have an idea of how to build the backdrop but would appreciate some feedback/tips.Dimensions:- 5' W x 7' H x 3' DMaterials: - Diagonal members: 0.1875" round bar- Circular votive holders: 0.125" round bar- Rectangular border, kickers, and base: 1/4" x 1" rectangular barI'm thinking that I will solder the diagonal members at each intersection and where the ends meet the rectangular bar frame. The base will be a 3' rectangular bar on the left and on the right. There will be a kicker on each side, connected to the base and about halfway up the vertical members of the frame.Does this seem feasible? Will the structure be stable? How can I form the circular votive holders?

Question by sjung510   |  last reply


how to prevent cracking when cutting a glass wine bottle in half?

I was attempting to cut a glass wine bottle in half to make some vases & other stuff.  I bought a bottle scoring kit (i think armour brand from Micheals Crafts)  The scoring worked OK, i don't think it scored well in a few places, but the tapping portion the kit said to do to seperate the halves didnt work at all.  I looked up online & it said about filling the bottle with boiling water then running an ice cube around the score line . . . this worked & split the bottle into 2 pieces as i wanted - only problem is it left a few cracks running vertically from the score line =( I can't use either piece now.  Is it just luck & practice makes perfect or is there a way to acheive this without cracking the bottle halves?  Any help is much apprecaited!

Question by Joolie567   |  last reply


CDROM stepper motor problem with movement

I have been having intermittent problems with my cdrom stepper motor. I had a four pin motor soldered to a bare copper wire. I used the pins not the little ribbon cable and I left the ribbon cable attached because I figured, as soon as I snip it off I would regret it later. The other end connects to a breadboard that is in line with the stepper input to the EasyDriver motor controller. I have been using GRBL controller on my PC and when I tested it the first time in a vertical position it would just wobble around, not moving up nor down. I thought the stepper motor was bad so I got another one. The second was wired the same way, 4-pins, and it worked in the vertical no problem. Then later, while working on the rest of my project the second cdrom motor that was working did that same wiggle without moving up or down. I realized that the solder connections were very close together and that two pins were electrically connected. I modified the wire to basically a homemade male to male jumper wire. The extra pin made the room I needed to unsolder the two pins. Once again the motor worked up and down with no wobble. I have done nothing to modify the cdrom stepper any further and went to test my motor today after a couple weeks hiatus and once again, wobble with no up nor down motion. At this point I am stumped. I have reason to believe that my solder skills are lacking and that my homemade jumper has broken internally inside my shrink tubing where I cannot immediately see it but If anyone else has had this problem and knows how to rectify it please let me know. I hope there is enough info here laying out my problem and that someone can lead me in the right direction. If it also helps, I have checked my pin out and I do not feel it is backwards or crossed. I checked the resistance between the four pins and the end of my "jumper" and is approximately, 40, 20, 40, 100 ohms for A-, A+, B-, B+, respectively. I am really not sure what these number would mean but my buddy told me to check the continuity from end to end.

Topic by dankozi713   |  last reply


Will my metal welder work ok?

I'm totally new to metal welding but am going to give it a try. My oven/range has a power outlet that reads on it: 125/250V, 50Amps. It has four prongs, three vertically oriented flat ones aligned as a triangle with the center one lower than the other two, and a fourth one top center that's round. My breaker box shows a 50Amp breaker for it. The welder says it's a MIG 170, 240V AC, 20Amps,single phase, 60Hz (Harbor Freight). I think the power I have is actually 220V but I'm not sure. If I do only have 220V will the welder only draw as much voltage as is asked by it - that is, if I only crank it up, say 3/4 of the way, will it draw less than its rated 240V? Or is that 240V just a maximum rating and it should run ok with 220V? It would seem odd that they would sell a welder that won't work for the power their customers would have by default without modifications. Also, where can I get a double socket for that outlet with one having an extension so I don't have to pull out my oven every time I need to weld something? Thank you. Bretina

Question by Bretina   |  last reply


Low pressure pneumatic grid (1 to 4 psi) to use small wind, small hydro and small solar power?

I have used low pressure air and a simple "airlift pump"  to cycle water around a "pallet  Garden" since August.  This meant that very little water was being used but the plants were growing really well.   the air comes from an aquarium bubble pump and it is about 1 psi.  The pallet garden is almost 20 ft from the little bubble pump.   Recently I decided to do something similar in my greenhouse, but it is 120 ft from the little pump and there is no electrical socket close.  So reluctantly I bought another 120 ft of 1/4 inch tubing to send the air to the greenhouse.  I didn't expect it to work at that distance.  But it is working great. Why not use air instead of electricity to move the energy from "toy" windmills in gardens? Or from low head small water power?  I bet anyone could make a compressor to make 1 PSI.  It is orders of magnitude easier than making a direct water pump or converting the energy to electrical and then back again in a pump.  An airlift pump is just a vertical tube in the water.    How simple is that!   and it is darn cheap too.  You can use this for pumping water (Highest I ever got was 18 ft with 1 psi) or just bubbling air into a fishpond or to actually move the water in small water features.   Or of course in the pallet garden or in aquaponics.  And even thought this energy is useful at that scale it can never ever be made worthwhile to share it electrically.  But maybe your grid could extend to your neighbours garden too?  You could have an interconnector if you or they have a bit of excess pneumatic power!

Topic by gaiatechnician   |  last reply


How would I build a Packing Peanuts Dispenser (ceiling mounted) for my home office (7' Ceiling)? Answered

I have looked all over the internet for a few days trying to find some DIY plans for building this and I haven't come across even one building plan for it. I know this is something a large number of people would love to find. I have a home business and I pack a ton of things at home for shipping. Commercial Packing Peanut (Loose Fill) Dispensers (Ceiling Mounted) are entirely too expensive for our small budget and I want to build my own. I have 7' ceilings and my packing station (table) is approx.  28.5" high. I would like the bottom of the dispenser opening (valve) to be approx. 20"-24" above the table so that I have some room to put boxes underneath it.  I would like the holding area (bag) to be able to hold between 10-15 cubic feet of packing peanuts so I don't mind if it takes up a lot of ceiling space. It wouldn't have to hang very far down from the ceiling as I can reach up that high to unhook/release it to refill it when I need to. The closer I could mount the top to the ceiling the better. I could either mount the dispenser to the ceiling from each corner of the bag or centrally mounted with a chain coming off each corner and meeting in the middle. It wouldn't matter to me either way. Here's a link to what I'm looking to build. http://a763.g.akamai.net/7/763/1644/4/app.infopia.com/img/image/fp/VPID/7237005/img4/img.jpg Of course, it needs to be not as deep as I have limited vertical space to work with. Anyone with any ideas with be greatly appreciated!

Question by SgtGang   |  last reply


TV antennas and what is possible indoors

Back in my young years a TV antenna was on the roof, quite big and only required to get 3 or 4 channels at best.The basic design of these Yagi antennas has not really changed since then.Same for the antennas required to get UHF and VHF channels at the same time.They either comes as two seperate antennas with a mixer or as a UHF antenna with some added loops for UHF.To talk some basics:For UHF you can get away with quite small dimensions for your antenna bits.After all a quarter wavelengths here is only around 15cm long.With VHF though we get already 30 to 40cm here depending on the channels.So called bradband antennas claim to be able to get a wide range of frequencies.That however is only true for their dedicated frequency band.If you take a normal whip style antenna then this becomes obvious - just compare the lenghts required and you realise "going the middle way" will mean neither UHF nor VHF would get any usable reception.For a long time now there is the option of so called "fractal antennas" to get better TV reception....Fractal antenna? What the heck is that?The theories behind them are about as old as fractal antenna designs that were not even considered to be fractals.Let me explain with the example of a standard FM radio antenna.For them we use frequencies from about 88 to 108MHz.And of course, for our cars they are always on the roof or mounted somewhere around the wheel arches.Some cars however does not seem to have any antenna depsite having a working radio.In this special case rest ensured they do have one, usually behind the plastic bumper bar ;)I like to go off road every now and then and lost count how many times I had to replace my antenna after getting to close to some bushes and trees.As a solution I used some thin wire to create a L-style anteanna on the inside of my windscreen.And funny enough it picks up more stations than a "proper" antenna outside.Really old design and if you think about it then an antenna with a kink that looks like L is ""self similar" - the definition of a fractal ;)More complex shapes like the Sierpinski models do exactly the same just in one more dimension.Cell phones use them as well as you WiFi router that has no external antenna anymore.Their designs and looks are so different that it is next to impossible to list the currently used shapes here.What it comes down to, when you just take a very basic flat or wire shape is that the straight single segment of the active antenna is split into one or many shorter segments that change the angle.They all have similar relations to the wavelenght still.Means really long segments might be half of a wavelength while the shortest bits are just 1/64 of a wavelength.Think of it (far too simple of course) like amny matched antennas combined into a single one.With that often comes a destinct radiation pattern, usually with a quite narrow beam angle that provides a quite high gain.Are fractal antennas any better than for example a proper Yagi antenna?You can ask 100 people and you get 100 different opinions for this one.This is mostly due to some simple facts like:Not caring about actual comparisons.Not being accurate enough when building the fractal antenna.Using just very basic equippment to compare results.For example when you have a 30 year old and quite small TV antenna on your roof and struggle with digital TV reception than you might want to just replace it all.In some case even the old rabbit ears on your TV set will work better.But take modern Yagi antenna with 12 or more segments and even station that are 100 miles away have a good chance.Comes down to possible gain, frequency match and of course how well the antenna is aimed at the transmitter.Then why is it that some fractal antennas still seem to perform so much better?The big antenna scam....If you paid attention during the intial DVB-T rollout in your country then noticed two things.a) You were told you need a TV or set top box capable of receiving DVB-T signals.b) You need a suitable antenna.Well, A is obvious but for B a lot of people got scammed badly.You see, in almost all cases the frequencies allocated for TV signal did not change at all.And an antenna really does not care if the incoming signal is analog or digital - it only cares about the frequency.But more and more local stations often meant that the trnsmit power is limited.After all it makes no sense to have a 500kW transmitter if the area to cover is only about 20 square km big.So people were told they need new antennas once the noticed digital TV is more like playing Tetris, blocks everywhere....You analog TV had no problem with a slightly weak signal, you did not really notice it unless the weather was really bad as well.All the benefits of digital TV however only work with a proper signal strength.If your areas still has both analog and digital TV channels then have a look on how your local transmitter provides the signals ;)Part of the big scam was hiding a very simple fact:All analog TV is transmitted in a horizontal orientation while almost all digital TV is transmitted in a VERTICAL orientation.Ok, we already gain and ignored it but why would the orientation be important?Your radio antenna is vertical because the FM signal is transmitted the same way - the "waves" if you like go up and down like a sine wave.You still get reception if you turn the antenna 90° to make it a horizontal one but you will realise that weak station are no longer available.The same happened with digital TV.And if there is only digital TV left in your area then simple turning your antenna 90 on the mast to have the single elements vertical instead of horizontal gives you top reception again ;)If you struggle to get all station then just try it out before buying a new antenna ;)Modern fractal TV antennas come paper thin and often with rediculous claims in terms of gain and range.On Fleabuy you can even find models claiming to get stations from over 2000 miles away LOLSome even come with the fake claim of being omnidirectional, meaning it does not matter where you place them or how you orient them.A fractal antenna can't change basic phsyics though...High gain mean highly directional or at least with a very flat radiation pattern instead of being more like a sphere.A high bandwidth means you compromise on the gain and/or the phsical dimensions.For example a thin whip antenna is quite limited in the optimum bandwidth while a piece of tubing provides amuch higher bandwidth but at the expense of gain (and some other problems).A fractal antenna can compromise between the two worlds much better than anything straight.And you would even need to make the traces on the plastic extremely wide because you can simply add different lengths for different frequencies.Means a wideband fractal antenna for FM, VHF and UHF basically is three different antennas combined into a single one.It also means that there is usually always more than just one single element of the antenna that is receiving a signal.If you experimented with WiFi antennas for your router or modem than you certainly found the famous Pringles can antenna - highly directional and with an insane amount of gain.Works exactly like a simple directional microphone.And you could, at least in theory do the same with a TV antenna - if there wouldn't be the problem of the wavelenght.A pringles can works for WiFi because the wavelenght only requires an antenna of about 3cm in lenght.You might not want a row of steel drums with a diameter of around 80cm on your roof just to watch the news though...Ok, if I need a new antenna anyway then should I get a fractal antenna or not?I try to make it simple:Roof option not possible or too costly AND your transmitter is not too far away then try one of the cheap paper thin antennas you find online.If you already have an antenna on the roof that is suitable for the frequencies you need then check it to know if it is still any good.With age and weather comes corrosion and some antennas are connected badly in this regard.Sometimes you are lucky and all it takes is to cut off a few cm of cable to get back to clean copper and to give the terminals on the antenna a good fine sanding or a wire brush treatment.In other cases you might find an amplifier under the roof that has faulty power supply ;)And well, certain animals love to chew through your cable...If all is goo from antenna to TV then as said try to flip the antenna 90° to get it vertical.No, I did not mean to point it up to the sky..... ;)I mean rotate it around the x-axis if X is pointing in the direction of the transmitter...

Topic by Downunder35m 


Tesla coil antenna?

With the cold and bad weather out there I started again to tinker with my old UHF radio.Trying to build a nice antenna to put on the roof of the hous and such things...While looking up on the various antenna designs I could not help it and followed a few links with antenna designs and specs for all sorts of frequencies.There are things like horizontal or vertical transmission waves or even circular ones.But also some of the basics can be quite different, like whip antennas, dipoles or coiled ones.The later we often see in these keyfob transmitters and receivers for door bells and similar low range, low cost options.Some really old ham radio links got me to the topic or electrically shortening and lenghtening antennas.Things like coils in a whip or added capacitors to match the antenna to frequency and transmitter.A tesla coil usually produces a lot of RF interference, not just on the main frequency it operates on.And from research and physics we learned that for really great distances you need really low frequencies.Like for example the very low bands used for submarine communication around the globe.Here antennas on land can be several km long...The inventor had a few ideas in terms of wireless electricity and communication but I wonder if there is more to it...Despite the broadband EMF a tesla coil produces it is also a really narrow beam antenna.Basically the radiation cone is orientated straight up instead of the usual horizontal patterns we use for communication.The topload again provides a spherical radiation pattern.I am wondering about how a tesla coil would operate as a directional antenna if the topload is replaced with a whip style antenna of a lenght that matches the wavelength...The hip would again provide a more or less spherical beam but the coil underneath would "puch" a directional from underneath.In the classic design the topload is meant to prevent arcing while providing a capacitor so the whole thing is resonant.At lower power arcing is no problem anyways, but what effect in terms of capacitance would a whip style antenna have?Classic pherical or donut style toploads provide little to no gain in terms of antenna properties.If you would use a sphere as an antenna for your CB radio then it would be perfect for very short distance but utterly useless for open range communication.We all know the fun of placing a flourescent light near a tesla coil to show "wireless electricity".Sadly this is more an effect caused by the high frequencies be able to produce the glow in the gas filling.Trying to make an incandescent lighbulb glow is far trickier.Several experiments show that two properly tuned tesla coils can work as transmitter and receiver.But to my knowledge no one ever tried this type of experiment with an antenna on the tesla coil...

Topic by Downunder35m 


Anti Gravity

SCIENTISTS in Finland are about to reveal details of the world's first anti-gravity device. Measuring about 12in across, the device is said to reduce significantly the weight of anything suspended over it.The claim - which has been rigorously examined by scientists, and is due to appear in a physics journal next month - could spark a technological revolution. By combating gravity, the most ubiquitous force in the universe, everything from transport to power generation could be transformed.The Sunday Telegraph has learned that Nasa, the American space agency, is taking the claims seriously, and is funding research into how the anti-gravity effect could be turned into a means of flight.The researchers at the Tampere University of Technology in Finland, who discovered the effect, say it could form the heart of a new power source, in which it is used to drive fluids past electricity-generating turbines.Other uses seem limited only by the imagination:Lifts in buildings could be replaced by devices built into the ground. People wanting to go up would simply activate the anti-gravity device - making themselves weightless - and with a gentle push ascend to the floor they want.Space-travel would become routine, as all the expense and danger of rocket technology is geared towards combatting the Earth's gravitation pull.By using the devices to raise fluids against gravity, and then conventional gravity to pull them back to earth against electricity-generating turbines, the devices could also revolutionise power generation.According to Dr Eugene Podkletnov, who led the research, the discovery was accidental. It emerged during routine work on so-called "superconductivity", the ability of some materials to lose their electrical resistance at very low temperatures. The team was carrying out tests on a rapidly spinning disc of superconducting ceramic suspended in the magnetic field of three electric coils, all enclosed in a low-temperature vessel called a cryostat."One of my friends came in and he was smoking his pipe," Dr Podkletnov said. "He put some smoke over the cryostat and we saw that the smoke was going to the ceiling all the time. It was amazing - we couldn't explain it."Tests showed a small drop in the weight of objects placed over the device, as if it were shielding the object from the effects of gravity - an effect deemed impossible by most scientists."We thought it might be a mistake," Dr Podkletnov said, "but we have taken every precaution". Yet the bizarre effects persisted. The team found that even the air pressure vertically above the device dropped slightly, with the effect detectable directly above the device on every floor of the laboratory.In recent years, many so-called "anti-gravity" devices have been put forward by both amateur and professional scientists, and all have been scorned by the establishment. What makes this latest claim different is that it has survived intense scrutiny by sceptical, independent experts, and has been accepted for publication by the Journal of Physics-D: Applied Physics, published by Britain's Institute of Physics.Even so, most scientists will not feel comfortable with the idea of anti-gravity until other teams repeat the experiments. Some scientists suspect the anti-gravity effect is a long-sought side-effect of Einstein's general theory of relativity, by which spinning objects can distort gravity. Until now it was thought the effect would be far too small to measure in the laboratory.However, Dr Ning Li, a senior research scientist at the University of Alabama, said that the atoms inside superconductors may magnify the effect enormously. Her research is funded by Nasa's Marshall Space Flight Centre at Huntsville, Alabama, and Whitt Brantley, the chief of Advanced Concepts Office there, said: "We're taking a look at it, because if we don't, we'll never know."The Finnish team is already expanding its programme, to see if it can amplify the anti-gravity effect. In its latest experiments, the team has measured a two per cent drop in the weight of objects suspended over the device - and double that if one device is suspended over another. If the team can increase the effect substantially, the commercial implications are enormous. Okay. lets throw down our ideas and see if we can figure something out... or not

Topic by RelyNupon   |  last reply


Linear magnetmotor - the basics for a beginner

Designing what is said to be impossible can be tricky, so I will try to give you some tips to reach your goal a bit quicker.A lot of people these days try to start with a wheel.Makes sense in one way as the final goal obviously is something that would rotate.However, considering angles in a rotating system is far easier with a usable baseline!We developed the liear motor well after any rotating electric motor.But only because someone already invented it for us.Making it flat was then more or less about finding a need for it first, like the modern highspeed trains on a maglev principle.If you want to make something move then it makes no big difference if you do it in flat or round.Flat however leaves you more options and much easier adjustments.And you will need a lot of the later...IMHO the best size and option for linear is the N0 model railway system.Tracks are only 3CM wide and second hand carriages to salvage the wheels is cheap.Either way, how would you start?We have multiple choices, like single row of magnets or double, maybe even tripple.Same for the actual magnet orientation.Flat, angled, attracting or repulsing...They all work if you understand how they actually work.Not the principle, the magnets ;)You see, a magnet always has two poles and without trickery both poles will be of even strenght, size, angle to each other and so on.Playing on a small and flat track with little resistance allows to use tiny magnets, like 5mm disc ones.If you follow the common concept of two magnet rows either side at a slight angle then you are half way there.People spent a lot of time trying not only to let the cart being attracted by the first magnets but also to let them pass out at the other end.In case you wonder why:Being able to be "sucked" in means you will have some force pulling on your cart from the next stage.Being able to fully pass through and preferably gain speed, means the cart would go from one set of magnets to the next - motion is accomplished.Let me give you my personal favourites for 5mm disc magnets:1. The rows are at an angle of 4-5° like a slim V-shape.2. Same as above by with the orientation changed by 90°The first basically means you have the magnets facing up while in the second you would have them mounted vertically.Both have good and bad sides and I think it is easiest to start with the first option.Here you would have a row of magnets at a slight angle either side of the track.Lets say it is all pointing away from you, then the north row would be left, south row on the right of the track.If you start narrow or wide depends if you want attraction or repulsion forces to work with.Again, it makes no big difference really, just a different way of operation, most seem to prefer repulsion though thinking the forces are greater - this is not true though ;)A very often copied way of mounting the working magnet (s) on the cart is by placing a magnet with south facing down on the left and one with north facing down on the right of the cart.Here you have the big problem of manipulating fields.The forces are quite strong and it seems the obvious choice but should be left for the advanced classes.Let me try to explain:No matter the site of your work magnet it has a very narrow acting field.Means you have a lot of attraction forces going only downwards and not providing any energy to move your system ;)If you orientate a magnet (stack) so north faces to the right and south to the left on either side of the cart you have more options.If the stack or single magnet has the correct length to match the angle of the magnet rows then a funny thing happens.Assume the outer most magnet is at about the same distance from center as the first magnet in the row.Means the inner most and opposing one is further away and the attraction forces gain the upper hand.While moving along though it moves away from the magnet row and whie still gaining force the last magnet in the row stops the cart dead center.This is the common scenario you see on the web when people try and fail.Now if you change the length of your working magnet and position in relation to the magnets in the row you can use the changes to your advantage.You can add slim disc magnets either side of your stack and observe the change in behaviour and where the cart starts to be repelled or gets stuck.In a bad case it starts fast but then stops with a big wobble back and forth.The perfect balance and size means the cart is attracted once it comes close to the magnet rows.There should only be a tiny sopt of very little repulsion right before the cart takes off.Like a hair trigger on a good gun if you know what I mean.It should then see some accelleration till about magnet 5-7 in a row of 14.From there it should level out and roll trough and keep rolling.I assume your first attempts now get you to the point where you cart start really nice, slows down a bit and seems just to miss a tiny extra push to make it out.It it shoots to the last magnet in the rows and then settles back to one or two before the end you are close!We have now two basic ways of manipulating the magnetic fields in our favour, or to "cheat" phsyics.Closing the gap.You will have realised by now that you need at least two stages for your system to be tested properly.Preferably 3 to get a 120° angle in a rotary conversion, but 5 would make sure there is hickups.This also means distance is now something to play with.Remember the pull before get at the same level with the first magnet in the rows?This is the first force we utilise by bringing the second stage at a distance CLOSE to take over the pull.Close because we don't want it to pull the cart out just like that.It would create a big "bump" and in a rotary system massive and unwanted vibrations.Instead we weaken the last magnet in either row.We still want to keep its pull but not so much the holding force that makes our cart go stuck here.Placing a magnet orientated in the same direction as your rows at the end of the row will change how and where the field of the last magnet in the row goes ;)Just to be precise: If the magnet in the row is north up and south down then the added magnet should have the poles 90° to that and in the same direction as the row.Depending how high, how close and with wich pole you place it the fields will change.You want to lower the locking force by at least 50% here - that will be suffient to overcome the holding force and gives the next stage a good chance to take over.It can also help to provide a sacrificial pole below the last magnet in the row.Again if north would be facing up then the lower magnet would also face north up but with a small distance to the upper manget.Ok, what happens here exactly?If I would want to be precise here you would need to read an awful lot, so make it simple...The lower magnet provides a way for the upper magnets south pole to get somewhere else instead of back to its original north pole.It also means there is another north pole "pushing" the north of the upper magnet more flat at the bottom half.This weakens the field strenght.Distance is key.The added magnet at the end does a similar thing.It provides attraction or repulsion forces that affect the field shape of the last magnet in the row.Imagine you have north facing towards the last magnet:You would push the last bit of the field up while also providing a very sharp end instead of a big round shape.The south pole of the last magnet also gets attracted by this added magnet, even more with one magnet below it.With those two added magnets you should be able to fully overcome the binding effect stopping your cart.It won't start and keep going when you let go of it half way down the track though, you need to start with the first magnet or give it a push to overcome the first binding effect.After that momentum takes over.If it really is that simple then where are all the successful videos about it?They are out there, you just need to look quite long for them.Most people still literally think only linear.A magnet has north and south and we can't change it - but we can...With field manipulations as above and shielding we get so much more than what physics currently dictates.Keep in mind that adding shielding under your rows of magnets will also affect how all works together ;)Some people forget this when using ferromagnetic things way too close to their testing area.Distance is also vital to keep in mind when experimenting.The closer two magnets are greater their forces to each other.You can utilise this for example by lowering magnets that seem to be far too strong in your configuration and cause a binding effect ;)And as said, shielding is nice thing for triack too - imagine what would happen with sielding on the sides of your magnet rows... ;)Make a negative into a positive!Extremly strong binding forces at a certain point in your track design can mean you might be able to utilise it instead of trying to waste it.Added magnets can divert the field to quite some extend.Shielding however can also direct them somewhere else - like in the core of a transformer where it all goes in a great circle.Even strips of shielding connecting magnets from one row to the one on the other side of the track can be utilised.Like that you turn two small magnets into one long one with twisted poles at the end.Provides more field strenght too and makes it good for areas with little to no attracting force to the cart.Then there is bigger design...Some people add a center magnet.With one on the cart and one in the center of the track you can create a cancellation field.The rows bind while the center magnet wants to push.If place where there is still enough forward momentum or even acceleration but close enough to the binding magnets it is possible to greatly lower the binding effect.But keep in mind you need to consider the added repulsion or compensated the field so it is most active towards the moving direction and less strong to where the cart is coming from.Advanced manipulations.You can machine magnets, sandpaper, file, grinder, CNC....Imagine you cut a square dice magnet from one corner to the other.Depending on how you have the field orientation you can end up several variations.But if north faced up in your dice then it will still face up in the cut pieces!Cut a pyramid and you end with a big flat south pole and a pointy north pole - and with extreme field strenth in this pointy bit.Similar story with half moon shapes.Imagine you machine a flat block magnet so you have a half moon with its pointy bits facing down and big round bit up.If north was up in the block and you shape the moon correctly then you end with two strong south pole points and a north pole that is strongest right between those points.Why is this so interesting you might wonder?Imagine you already know a magnets pole does not care if gos back to its own opposite or that of a different magnet.Then you also know you can machine and shape magnets to your will.Now imagine that for a change:Precisely machined pyramids that have the top chopped off.All tops in this example facing being the north poles and big bottom south.If you then machine a precise iron core block you make a nice cube.With magnets we need really good glue and a good press to make it happen.But if the center core is of proper size then we end with a block magnet that has a south pole on all sides.Of course to be 100% perfect we would need a zero tolerance gap but good glue and high forces can come quite close.Works as a sphere too but would even have clue where to start to machine the magnets LOL

Topic by Downunder35m 


heliostat and sun tracker basic program

In the late 1980s, I designed, built and programmed a computer-controlled heliostat. Its mirror reflected sunlight into my living-room, making it much brighter. It worked excellently with almost no attention for many years, until a neighbour's tree grew and blocked sunlight from reaching the mirror. The computer was a Commodore VIC 20, which was old even then, and had only 4.5 kilobytes of memory. The program I wrote, in Commodore BASIC, fitted into that space and handled all the control functions. It even included a few "bells and whistles". For example, at night-time the mirror was automatically parked face downward to reduce the buildup of dust. That particular program would work only on a VIC, and I haven't seen any of those for many years. However, I have recently taken the astronomical and trigonometrical parts of the program and made them into a new program which I'll append below. It calculates the position of the sun in the sky, as azimuth (true compass bearing) and angle of elevation, as seen from anywhere on the earth at any time on any date. It also calculates the required orientation of a mirror if it is to reflect sunlight in any desired direction. With the addition of some code to enable the computer to control motors, this could become the software for a computerized sun-tracker or heliostat. I'll append two versions of the program. The first is in QBasic, and contains quite a lot of explanatory comments. The second version is in a very generic BASIC, and has been tested on many implementations of the language. It even has line numbers! Personally, I prefer the QBasic version. The coding is more elegant. However, the generic version is likely to be useful to more people. It's public-domain. Use it for any purpose, even commercially. Enjoy! dow ' SunAlign.BAS (Version for QBasic and similar dialects) ' Calculates position of sun in sky, as azimuth (compass bearing ' measured clockwise from True North) and angle of elevation, as ' seen from any place on earth, on any date and any time. ' Also calculates alignment of a heliostat mirror. ' David Williams ' P.O. Box 48512 ' 3605 Lakeshore Blvd. West ' Toronto, Ontario. M8W 4Y6 ' Canada ' Initially dated 2007 Jul 07 ' This version 2008 Jan 13 ' All angles in radians except in i/o routines DegIn and DegOut DECLARE SUB C2P (X, Y, Z, AZ, EL) DECLARE SUB P2C (AZ, EL, X, Y, Z) DECLARE FUNCTION Ang (X, Y) DECLARE SUB DegIn (P$, X) DECLARE SUB DegOut (P$, X) CONST PY = 3.1415926536# ' "PI" not assignable in some BASICs CONST DR = 180 / PY ' degree / radian factor W = 2 * PY / 365 ' earth's mean orbital angular speed in radians/day WR = PY / 12' earth's speed of rotation relative to sun (radians/hour) C = -23.45 / DR ' reverse angle of earth's axial tilt in radians ST = SIN(C) ' sine of reverse tilt CT = COS(C) ' cosine of reverse tilt E2 = 2 * .0167 ' twice earth's orbital eccentricity SN = 10 * W ' 10 days from December solstice to New Year (Jan 1) SP = 12 * W ' 12 days from December solstice to perihelion CLS Menu: PRINT "1. Calculate sun's position" PRINT "2. Calculate mirror orientation" PRINT "3. Calculate both" PRINT "4. Quit program" PRINT PRINT "Which? (1 - 4)"; DO S% = VAL(INKEY$) LOOP UNTIL S% >= 1 AND S% <= 4 PRINT S% IF S% = 4 THEN END ' Note: For brevity, no error checks on user inputs PRINT PRINT "Use negative numbers for directions opposite to those shown." PRINT DegIn "Observer's latitude (degrees North)", LT DegIn "Observer's longitude (degrees East)", LG INPUT "Time Zone (+/- hours from GMT/UT)"; TZN INPUT "Time (HH,MM) (24-hr format)"; HR, MIN INPUT "Date (M#,D#)"; Mth%, Day% PRINT CL = PY / 2 - LT ' co-latitude D = INT(30.6 * ((Mth% + 9) MOD 12) + 58.5 + Day%) MOD 365 ' day of year (D = 0 on Jan 1) A = W * D + SN ' orbit angle since solstice at mean speed B = A + E2 * SIN(A - SP) ' angle with correction for eccentricity C = (A - ATN(TAN(B) / CT)) / PY SL = PY * (C - INT(C + .5))' solar longitude relative to mean position C = ST * COS(B) DC = ATN(C / SQR(1 - C * C)) ' solar declination (latitude) ' arcsine of C. ASN not directly available in QBasic LD = (HR - TZN + MIN / 60) * WR + SL + LG ' longitude difference CALL P2C(LD, DC, sX, sY, sZ) ' polar axis (perpend'r to azimuth plane) CALL C2P(sY, sZ, sX, sAZ, sEL) ' horizontal axis CALL P2C(sAZ - CL, sEL, sY, sZ, sX) ' rotate by co-latitude IF sZ < 0 THEN BEEP PRINT "Sun Below Horizon" PRINT GOTO NewCalc END IF IF S% <> 2 THEN ' calculate and display sun's position CALL C2P(sX, sY, sZ, sAZ, sEL) ' vertical axis DegOut "Sun's azimuth: ", sAZ DegOut "Sun's elevation: ", sEL PRINT END IF IF S% > 1 THEN ' calculate and display mirror orientation PRINT "For target direction of light reflected from mirror:" DegIn "Azimuth of target direction (degrees)", tAZ DegIn "Elevation of target direction (degrees)", tEL PRINT CALL P2C(tAZ, tEL, tX, tY, tZ) ' target vector X,Y,Z CALL C2P(sX + tX, sY + tY, sZ + tZ, mAZ, mEL) ' angle bisection by vector addition PRINT "Mirror aim direction (perpendicular to surface):" DegOut "Azimuth: ", mAZ DegOut "Elevation: ", mEL PRINT END IF NewCalc: PRINT PRINT "New Calculation" PRINT GOTO Menu FUNCTION Ang (X, Y) ' calculates angle from positive X axis to vector to (X,Y) SELECT CASE SGN(X) CASE 1: Ang = ATN(Y / X) CASE -1: Ang = ATN(Y / X) + PY CASE ELSE: Ang = SGN(Y) * PY / 2 END SELECT END FUNCTION SUB C2P (X, Y, Z, AZ, EL) ' Cartesian to Polar. Convert from X,Y,Z to AZ,EL EL = Ang(SQR(X * X + Y * Y), Z) A = Ang(Y, X) IF A < PY THEN AZ = A + PY ELSE AZ = A - PY END SUB SUB DegIn (P$, X) ' Input angle in degrees and convert to radians PRINT P$; INPUT N X = N / DR END SUB SUB DegOut (P$, X) ' converts radians to degrees, rounds to nearest 0.1, and prints S$ = LTRIM$(STR$(INT(10 * ABS(X * DR) + .5))) IF S$ = "3600" THEN S$ = "0" IF LEN(S$) = 1 THEN S$ = "0" + S$ IF X < 0 THEN IF VAL(S$) THEN S$ = "-" + S$ PRINT P$; LEFT$(S$, LEN(S$) - 1); "."; RIGHT$(S$, 1); " degrees" END SUB SUB P2C (AZ, EL, X, Y, Z) ' Polar to Cartesian. Convert from AZ,EL to X,Y,Z Z = SIN(EL) C = -COS(EL) X = C * SIN(AZ) Y = C * COS(AZ) END SUB 100 REM SunAlign.BAS (Generic BASIC version) 110 REM Calculates position of sun in sky, as azimuth (compass bearing 120 REM measured clockwise from True North) and angle of elevation, as 130 REM seen from any place on earth, on any date and any time. 140 REM Also calculates alignment of a heliostat mirror. 150 REM David Williams 160 REM P.O. Box 48512 170 REM 3605 Lakeshore Blvd. West 180 REM Toronto, Ontario. M8W 4Y6 190 REM Canada 200 REM Original date 2007 Jul 07. This version 2007 Oct 07 210 REM Note: For brevity, no error checks on user inputs 220 CLS 230 PRINT "Use negative numbers for opposite directions." 240 INPUT "Observer's latitude (degrees North)"; LT 250 INPUT "Observer's longitude (degrees East)"; LG 260 INPUT "Date (M#,D#)"; Mth, Day 270 INPUT "Time (HH,MM) (24-hr format)"; HR, MIN 280 INPUT "Time Zone (+/- hours from GMT/UT)"; TZN 290 PY = 4 * ATN(1): REM "PI" not assignable in some BASICs 300 DR = 180 / PY: REM degree/radian factor 310 W = 2 * PY / 365: REM earth's mean orbital speed in radians/day 320 C = -23.45 / DR: REM reverse angle of axial tilt in radians 330 ST = SIN(C): REM sine of reverse tilt 340 CT = COS(C): REM cosine of reverse tilt 350 E2 = 2 * .0167: REM twice earth's orbital eccentricity 360 SP = 12 * W: REM 12 days from December solstice to perihelion 370 D = INT(30.6 * ((Mth + 9) MOD 12) + 58.5 + Day) MOD 365 380 A = W * (D + 10): REM Solstice 10 days before Jan 1 390 B = A + E2 * SIN(A - SP) 400 C = (A - ATN(TAN(B) / CT)) / PY 410 ET = 720 * (C - INT(C + .5)): REM equation of time 420 REM in 720 minutes, earth rotates PI radians relative to sun 430 C = ST * COS(B) 440 EL = ATN(C / SQR(1 - C * C)) * DR: REM solar declination 450 AZ = 15 * (HR - TZN) + (MIN + ET) / 4 + LG: REM longitude diff 460 GOSUB 800 470 R = SQR(Y * Y + Z * Z) 480 AX = Y: AY = Z: GOSUB 710 490 A = AA + (90 - LT) / DR 500 Y = R * COS(A) 510 Z = R * SIN(A) 520 GOSUB 740 530 PRINT : REM AZ & EL are now sun's azimuth & elevation in degrees 540 IF EL < 0 THEN PRINT "Sun Below Horizon": END 550 R = AZ: GOSUB 870: PRINT "Sun's azimuth: "; R; " degrees" 560 R = EL: GOSUB 870: PRINT "Sun's elevation: "; R; " degrees" 570 PRINT 580 INPUT "Calculate heliostat mirror alignment (y/n)"; K$ 590 IF K$ = "N" OR K$ = "n" THEN END 600 SX = X: SY = Y: SZ = Z 610 PRINT 620 INPUT "Azimuth of target direction (degrees)"; AZ 630 INPUT "Elevation of target direction (degrees)"; EL 640 GOSUB 800 650 X = X + SX: Y = Y + SY: Z = Z + SZ: GOSUB 740 660 PRINT : REM AZ & EL are now aim azimuth & elevation in degrees 670 PRINT "Mirror aim direction (perpendicular to surface):" 680 R = AZ: GOSUB 870: PRINT "Azimuth: "; R; " degrees" 690 R = EL: GOSUB 870: PRINT "Elevation: "; R; " degrees" 700 END 710 IF AX = 0 THEN AA = SGN(AY) * PY / 2: RETURN 720 AA = ATN(AY / AX): IF AX < 0 THEN AA = AA + PY 730 RETURN 740 AX = SQR(X * X + Y * Y): AY = Z: GOSUB 710 750 EL = AA * DR 760 AX = Y: AY = X: GOSUB 710 770 AZ = AA * DR 780 IF AZ < 180 THEN AZ = AZ + 180 ELSE AZ = AZ - 180 790 RETURN 800 E = EL / DR 810 A = AZ / DR 820 Z = SIN(E) 830 C = 0 - COS(E): REM Won't work without "0" in Liberty Basic 840 X = C * SIN(A) 850 Y = C * COS(A) 860 RETURN 870 R = INT(10 * R + .5): IF R = 3600 THEN R = 0 880 R = R / 10 890 RETURN

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