## Step 7: Circuit:

This is the circuit:
<p>As I was walking home from school, I thought of something like this, but used the motion of walking to generate electricity. The problem is, I want it to be small enough to fit and look decent on my shoe. I did a couple of test runs but i think maybe I didn't use enough coil. The magnet wire only covered about 1/4&quot; high and 1/2&quot; long. Is that enough to generate any current, or is that not the problem? I also tested with the voltimeter and got nothing... I am using 3mm by 1mm neodymium magnets in two stacks together. </p>
A few people have mumbled about using a capacitor in this project rather than a battery, simply because it's easier to get. I was told by some guy at a battery store that something like a 1000 uf capacitor should be able to power an L.E.D. for a couple of minutes. I don't remember all my stuff about analog electronic and I'm too lazy to dig up my notes to do the math so I have two questions. First, would a capacitor (of 1000 uf or higher) be something worth trying in this circuit? And secondly, if it is worth trying, how should it be hooked up? I have a feeling that just hooking up the capacitor straight to the DC input and having the switch cause it to discharge wouldn't work (of course with the correct resistors to drop the voltage), but I don't really know.
<p>I tested this theory, I used Jamicon WG105&deg;C 16V 1000uF capacitor, 4,7k resistor and a red LED. Supplied 12 volts for a moment and it light it only for 10 seconds of useful and 30 seconds of visible light. I suggest try to use a 1F capacitor for this purposes, as the capacitor is only thing that doesn't need charging controller to operate many thousands charging cycles and doesn't get damaged from overcharging, left uncharged or deep discharging.</p>
I am beginning this project today with a cap instead of the battery. I'll post how it goes. It should turn out to be similar, since a battery is in essence a capacitor.
How much amp you can make with this?
<p>also will it work with a 100 uF compacitor instead of the rechargable battery?</p>
The problem with capacitors is that their energy density is extremely low compared to batteries, so your light will only stay on for seconds instead of minutes after charging it.
<p>ok thank you, I am all cleared now and I look forward to making this, bye</p>
<p>sorry about all the questions but also where did you get plastic washers that fit and/or what brand/type are they</p>
<p>hey I am only 12 so I was a little confused,why can't you just put one recifitor diode on the posotive and one on the negative instead of bridging them? And will it still work if the recifitors are 1N4005 instead of 1N4007?</p>
Hello makershaker, is great that you are interested in this stuff at your young age! The only difference between the 5 and the 7 is their reverse breakdown voltage, which doesn't matter for this project. Your other question can be answered by Goggling &quot;full-wave vs bridge rectifier.&quot; Basically, using two diodes instead of 4 saves you some power but it requires a special center-tapped input. You could actually do this since you are making the coil anyway, but it would be harder to do.
<p>Holy crap. 621 comments!!!</p><p>I'm glad some warnings and modifications are being suggested. Will get around to reading at least some of these comments. </p><p>I just took apart an old audio tape-head de-gauser and found it to be a coil with a rod in the center. The channel also happened to fit nicely with some standard neodym magnets I have (though I may need more). But perhaps before I tinker further, I may have to hunker down with these comments.</p><p>There is another makezine plan for a &quot;vampire&quot; LED flashlight, using a toroid and a Joule Thief circuit. This allows lower voltage to run an LED. I might try merging these two plans.</p>
<p>Brilliant! </p>
Too bad you can buy 1 for cheaper than u can make 1
i just wanna know can i switch the rechrgable battery with capacitor??
You can. You'll need a super capacitor if you want to keep it small and power the light for any significant amount of time. Any cap with a voltage above the minimum voltage for your LED will work though, but it's not going to last very long at all.
How would the capacitor charge? It is my understanding that the cap will only charge to if a higher current is being fed into it, so if the shake light is only capable of producing x amount of volts, then the cap will only charge up to x amount of volts. It doesn't trickle charge and gain more energy potential like a battery. Or so is my understanding. Please, let me know what you found out.
That's a good point, I didn't consider that. I'm not sure about the specifics of the voltage output by the coil but I hypothesize you could have a small dc-dc boost circuit to charge the cap, similar to a camera flash circuit. It charges a very high voltage cap with a single AA cell.
Making the coil as short as possible will increase its output as only the few turns near each end of the magnet are producing any output.
Please let me share my experience working on this project. I have 3 Neo magnets 10 mm in diameter x 10 mm length housed in a plastic tube ID = 11 x OD = 13 mm with 1300 turns of AWG #28 magnet wire(0.30 mm). The coil length is 50 mm. The tube length is 150 mm. I have provided spring on both ends of the 3 magnets attached to each other acting as one long magnet. Shaking the finished assembly gave me 7.4 volts. I tried recharging my phone and it gave 33% charge after rigorous shaking for 15 minutes. I am not satisfied with the result so I have to make a new coil assembly using bigger magnets of 22 mm in diameter and 25 mm in length. My target is to shake COMFORTABLY( I am thinking how old folks could shake it without losing their arms). By the way, I used 4700 uF capacitor and skottsky diodes for my rectifier as well as germanium diodes.
Realizing the "Shake It Like a Tic Tac" project will not work, I have designed a coil and magnet arrangement that will illuminate a white LED when a Tic Tac box is shaken. The "Shake It Like a Tic Tac" project will not work as the coil is longer than the magnet and any voltage induced in the turns from the North pole will be negated by the flux produced by the south pole. The final result is zero. The only reason why the developer of the above project released the project was due to a small charge in the rechargeable cells leading him to deduce the project was successfully producing a current. It reminds me of the release of Cold Fusion by Pons and Fleishman, before they thoroughly investigated their results. I don't want anyone to waste their time attempting this project and being disappointed. Magnetism and electromagnetic energy is difficult enough to comprehend without the frustration of going down the wrong path. The small magnet used in the project above does not give enough flux to produce a worthwhile output. The magnet I have used is 20mm diameter and slides sidewards past two coils of 600 turns each and wired so that the voltages combine. In addition, the output charges two separate 470u electrolytics via single diodes so that you are not losing 1.2v from the generated voltage. The white LED taps across the two electrolytics (in series) - another clever innovation. The output is not very bright but it is the maximum obtainable from this type of arrangement. It is far greater than using small magnets in a tube and bunching the winding so that it is as narrow as possible. I will be adding the project to Instructables very soon, but in the meantime I can be contacted at: TALKINGELECTRONICS.COM Colin Mitchell talking@tpg.com.au
ummm it obviously works if theirs a picture of it working!!
But... There isn't a picture of it working! Or is there? If there is, then I have been mistaken, I didn't not see it.
There is no picture of it working. The only reason why the author of the project thought the device was charging the battery was due to him using a battery that was already partially charged, and therefore he could not tell if the coil/magnet assembly was functioning.
Please let me share my experience working on this project. I have 3 Neo magnets 10 mm in diameter x 10 mm length housed in a plastic tube ID = 11 x OD = 13 mm with 1300 turns of AWG #28 magnet wire(0.30 mm). The coil length is 50 mm. The tube length is 150 mm. I have provided spring on both ends of the 3 magnets attached to each other acting as one long magnet. Shaking the finished assembly gave me 7.4 volts. I tried recharging my phone and it gave 33% charge after rigorous shaking for 15 minutes. I am not satisfied with the result so I have to make a new coil assembly using bigger magnets of 22 mm in diameter and 25 mm in length. My target is to shake COMFORTABLY( I am thinking how old folks could shake it without losing their arms). By the way, I used 4700 uF capacitor and skottsky diodes for my rectifier as well as germanium diodes. <br>
sir, could you build your own and post an instructable?
Yes there is look at the last pic in step 9!!!!!!!!!!!!!!!!!!!<br />
ehem! last step 5th picture
That's not it working. If it was working then the light produced would be ridiculously small, which would make this project, despite the fact that it works. Notice the "If". I agree it doesn't work. PS: Eric showed the guy this Instructable on lunchmeet.
last step 5th picture
I know exactly what you mean about the north and south pole working against each other. It would generate a bit of electricity though as the magnet gets close enough to either end of the tube, not as much as it possibly could though. Say the tube is 3 inches long and the collection of magnets is 1 in long. The coil should begin at one end, progress for one inch, stop, the wire should then be parallel to the tube for the next inch, and coiled in the other direction for the last inch. Maybe I'll draw a picture.
i have made it and it works , even when i short out the capacitor,when i connect the shaker seperately on a voltometer i get .7 volts
EXACTLY. I was reading this project and I'm thinking, &quot;what is going on here? This design CAN'T work!?&quot; If you look at something commercial like the &quot;forever flashlight&quot; you can see the travel of the magnet is much longer than the coil. This design wouldn't produce any significant voltage, and I can't imagine how much time he wasted winding those coils. I would be very interested in reading your instructable. Is it up yet?
SHAKE TIC TAC LED TORCH In the diagram, it looks like the coils sit on the &ldquo;table&rdquo; while the magnet has its edge on the table. This is just a diagram to show how the parts are connected. The coils actually sit flat against the slide (against the side of the magnet) as shown in the diagram: The output voltage depends on how quickly the magnet passes from one end of the slide to the other. That's why a rapid shaking produces a higher voltage. You must get the end of the magnet to fully pass though the coil so the voltage will be a maximum. That&rsquo;s why the slide extends past the coils at the top and bottom of the diagram. The circuit consists of two 600-turn coils in series, driving a voltage doubler. Each coil produces a positive and negative pulse, each time the magnet passes from one end of the slide to the other. The positive pulse charges the top electrolytic via the top diode and the negative pulse charges the lower electrolytic, via the lower diode. The voltage across each electrolytic is combined to produce a voltage for the white LED. When the combined voltage is greater than 3.2v, the LED illuminates. The electrolytics help to keep the LED illuminated while the magnet starts to make another pass.
I just built this a flashlight by exactly the same specs as shown in this project except I used a capacitor instead of a battery and it works brilliantly. I can short the capacitor and then charge it up to five volts. Colin you are wrong in you statement about this not working the statement is pompous and ill thought out.
How many turns did you put on the coil?
I have no clue how many turns I did, I just fixed my pipe (I used a medical syringe with the piston taken out) to the sewing machine and slammed down on the pedal. Colin I recoment that you build one of these so that you can participate in the discussion not only from the theoretical side. Be a participant and not a spectator. One point I want to tell everyone is that using Shotky diodes could be benificial because of their low voltage drop.
If you don't know how many turns you put on the coil and your project worked, maybe you can answer all the emails I get from readers who did not get their project to work.
Of course I can. So lets begin: 74% of your correspondents failed to burn or scrape the insulation of the copper wire for the coil. This can be remedied by burning or scraping the end of the copper and solder it back in place. 18% of them connected the diode bridge the wrong way round (boy is that embarrassing). 82% are using broken batteries (shorted or too high resistance) or too big batteries (takes forever to charge). A capacitor is good during development because its behavior is more reliable. 23% have a short in the coil or the copper is broken somewhere. Measure it and you will see if its broken. You could possibly measure the resistance to see if it is shortened but I do not really know what to expect from that measurement. 17% never actually tried but like socializing and theorizing online. 42% have analysis-paralysis and can not start without solving it in their head before beginning... like how many turns do I have to have on the coil? How much current can I generate? How big should the magnet be? Does the length of the pipe matter? 6% have a cold soldering point somewhere. 100% of them are seeking help from someone that has not managed to get it to work in the first place. (kindling the cinder to a flame.) Some people may fall into more than one category. 95% of all statistics are made up on the spot.
Thats a total of 467%...Something is not right here
&nbsp;Well it kind of is right. If I have 100 people in a hall i might say that 30% of them had coffee this morning - that's 30 people. I could also say that 99% percent of the people in the hall went to sleep last night - thats 99 people. that doesn't mean i have 129 people :P
You fail to calculate that 64% of those mentioned fall into 31.4% of the categories mentioned....
Well then...ITs still 400%
Percentages are like magic.
Ah...O...K?
Quote one.
Obviously I have not seen your arrangement but bunching up the coil will make the whole arrangement much more efficient.
That was not the issue. You claimed that this would not work but it does. It may be inefficient and impractical but it works brilliantly. You should try it. Its fun.
What makes you think it does not work,can't you see the picture? Or did i miss something?