Ac Powered Led Circular Magnifier Work Lamp

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AC Powered White LED Circular Magnifier Work Lamp by arcticpenguin on March 9, 2008

Table of Contents intro: AC Powered White LED Circular Magnifier Work Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 1: Background to the LED light bulb idea. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 2: It is not just Environmentally Green . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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File Downloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 3: Tools, Parts and Stuff you'll need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 4: It needs to be stated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 5: Lower Power Unit Dissection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 6: Upper Unit Dissection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 7: Layout of the new lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 8: Holing the donut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 9: LED Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 step 10: Assembling the lamp head unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 step 11: Power On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 step 12: There you have it! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Make Magazine Special Offer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

intro: AC Powered White LED Circular Magnifier Work Lamp , Use bright LEDs to replace florescent circular light in magnifier work lamp. Let there be light! A medium difficulty Instructable to fix a circular magnifier work lamp by converting to a very low energy, high reliability alternative light source that avoids using mercury contaminated florescent light bulbs.

step 1: Background to the LED light bulb idea. , Ok, so I cannot turn down a challenge either. I bought this really nice, nearly new, Magnifier Work Lamp for only $4 in a local Thrift Shop. Great bargain, says I, these regularly retail for $50 to $100 and this was a good one. So what if the bulb is blown, says I, as I noticed it would not light when I plugged it in before buying. New bulbs can not cost that much, right? Hahaha. What a bargain, says I! At home, I tried easy fix #1... replace the bulb... Darn! Still not working! Followed with easy fix #2... take apart the power box near the base. Yay! Found a wire shorted beneath the cover plate screw. Noted the electrical flash marks by the screw hole. See pix. Repaired insulation and tested the lamp. Darn again! Next was easy fix #3... take the light head apart (instructions below) Triple Darn! Looked good. Most likely, the little lamp starter card part (mine was heat-shrink in black) was blown during the short circuit in the lower power box. Spent the next few days in electrical supply stores learning that the little lamp starter card part that leads power to the lamp is not available in my area. Crap Darn! Just not going to be my week was it? Better get this fixed or I just blew my $4 and possibly my reputation.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

step 2: It is not just Environmentally Green , My Honest Admission - The so-called Green aspect to saving electricity never even crossed my mind until the project was completed. But then if you need an environmentally friendly science project idea? Then a light went on above my head. Figuring that LEDs are getting cheaper and brighter all the time, I would try using a group of LEDs, but I needed a circuit. At [www.DiscoverCircuits.com DiscoverCircuits] I searched for LED and found this interesting article, with some pix. AC Powered White LED Strings designed by David A. Johnson, P.E. May 14, 2007 A while back a guy by the name of Ken Schultz sent me a simple drawing of how he connected a string of 30 LEDs, to make a nice under the counter accent light, powered by 120vac. He wired the strings in two series sections of 15 LED each, but wired in opposite directions. He then used just one capacitor to limit the AC current through the two stings. I looked at the circuit and decided that it seemed quite reasonable. The only change I decided to make was to add a metal oxide resistor in series with the capacitor, to act as fuse and to limit the peak current, should there be a voltage spike on the AC line. With the two strings of 15, the current is first pumped through one series string, and then as the AC line polarity changes, it flows through the second string. Since the capacitor acts as a constant current source, you can use other string numbers. The capacitor value shown keeps the current limited to about 20ma for the LEDs. In Europe and Australia, where the line frequency is 50Hz, you may see a noticeable strobing of the LEDs, if there is substantial separation between the two different polarity strings." "Soktha from France ([email protected]) sent me his version of this circuit, using two strings of 14, for a total of 28 white LEDs. He mounted the LEDs onto a wood stick. When powered up from a 240vac 50Hz source, the devices provided a nice white light. Seems it does not matter how many LEDs are used if they are somewhat balanced. As well a bonus, is it should works worldwide on wall power. The schematic is a pdf file.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Schematic states 0.47uf 250V capacitor, while this is a 0.22uf capacitor. I followed the schematic diagram. 2. Can't make out the color code on this but schematic calls for 1K 1W resistor.

Image Notes 1. Seems to me his layout doesn't match the schematics. I wired according to the schematic diagram.

File Downloads LED strip 0 light schematics pdf.pdf ((792x612) 11 KB) [NOTE: When saving, if you see .tmp as the file ext, rename it to 'LED strip 0 light schematics pdf.pdf']

step 3: Tools, Parts and Stuff you'll need , Lots of LEDs, I bought a pack of 100 on ebay (JELED Electronic Co Ltd, Hong Kong) for about $20. These are the Jumbo 10mm, white LEDs, 140,000mcd (confusing light units), and 20mA. Just get lots of the brightest you can find. I used 60, but next time I may use all 100 focused to different focal distances. These also came with 100 matching resistors (we do not require these here). 1x Capacitor - 0.47uf 250V, non-electrolytic 1x Resistor - 1K 1Watt, metal oxide 1x Square foot of white painted paneling, cardstock or such (not metal) Drill with small bit (1/16inch) and one big one (larger than your scroll saw blade) Scroll saw Screwdriver Solder, iron, etc Masking tape Crimp terminals are quick and easy but you can also solder and of course duct tape, naturally! (What is a project without it?)

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

step 4: It needs to be stated , OK, Here it comes - IT IS ELECTRICITY FOLKS, THINK SAFETY! If you electrocute yourself, it is your fault that 120volts is rushing through your body, and you should have listened when I tell you to make sure to UNPLUG THIS UNIT WHILE WORKING ON IT. There will be LIVE WALL POWER EXPOSED AT CERTAIN TIMES. Kids, get an adult to help. Consider yourself warned!

step 5: Lower Power Unit Dissection , Pull the plug from any power source and do not put it back in until the last step. Take the lower power box apart. Note the wiring, as yours might be slightly or totally different to mine. Inside the power box I found - the ground (green) wire connected to the power box wall with a screw - the neutral (white) wire went directly to the lamp head - the hot (black) wire connected in series through the ballast coil then went to the lamp head. Simply remove the ballast coil and crimp the capacitor between the two black wire ends. Cut the white wire and crimp the resistor between the white wire ends. Insulate any exposed metal (I used heat shrink but electrical tape will work fine). Close the power box with the cover plate.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Black marks at screw from electric short. 2. Discard this transformer/choke.

Image Notes 1. Remove 2 screws.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Capacitor 0.47uf 250V non-electrolytic. Heatshrink or tape. 2. Resistor 1K 1W metal oxide. Heatshrink or tape. 3. Cover screws. 4. Black marks from electric short.

step 6: Upper Unit Dissection , Take apart the lamp head unit. Remove and save the flimsy plastic light diffuser shell. Discard the florescent lamp, unless it is still good. Remove and save the three lamp clips and screws, being careful of the heavy glass lens, mine did not break somehow when I dropped it on the concrete floor. From this point on the lamp head unit is not heavy enough to counter the arm springs and will rise. Discard the white reflector metal piece complete with plug and lamp starter part (mine was heat shrinked in black), retaining most of the wire available. Electrically speaking, you should now have the black and white whites from the lower power box; the black goes through the on/off switch and ends, while the white wire just ends. (Using existing wire saves having to snake feed new wire). Note that on mine the black wire is crimped to a short piece of white retained from the discarded parts, consider this still the black wire, you may want to color it with a marker for future). If you use a meter to verify 120Vac present and the switch is working remember to again unplug after.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Lens and light shield held on by 3 screws 2. On/Off switch

Image Notes 1. Modify all three of these clamps. This one is close to original shape. 2. Cut each clip and save this part. 3. Discard these parts.

step 7: Layout of the new lamp , Tape the nice surface of the white board with masking tape to protect from scratches during all the handling required and to provide a surface to draw on. It also helps keep the cutting and drilling neat. Remember to measure twice and cut once. A large circle-drawing compass is most handy in laying out the project. Cut the white board piece to a round circle of a diameter just less than the diameter of the light head, my circle was 8.7 inches (221mm). Band saws work great for this, but a scroll saw will work as well. Layout and draw the inner circle just larger than the lens; do not cut this out until the holes are drilled. I was able to insert my circle partway and used the open lens hole to trace a draft circle. Then I corrected the trace to make this circle a bit larger. My circle was 5.2 inches (132mm). Ok, here is the tough part. You need to draw the four equally spaced circles that the LED's will be aligned on, then divide the circles evenly depending on how many LEDs you use. Since I decided to make my light strings 2 sets of 30 LEDs in series with each set of 30 consisting of 2 strings of 15 LEDs in series. I needed to divide each of my 4 circles into 15 equal sections. I found that my circles were too close to fit the jumbo LEDs perpendicular to the circles. I tried to get fancy with a spiral effect. Now go do it. To make it easy to layout the 2 holes per LED I then used a small circle (same diameter as the LED legs are wide) to speed layout.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. After all the small holes are drilled make this hole to start the scroll saw to cutout center.

step 8: Holing the donut , Then use a drill (a drill press is great here) to make 2 holes per LED. Make the holes where each small circle crosses the large circle lines so the LED can be tuned in or out to direct the light to the focal point near the lens. Now use the large drill bit to make a hole somewhere within the inner circle. Cut out the inner circle to finish "the donut" with a scroll saw. If you are following closely you will notice I cheated the order a bit for the pix. At this point remove the masking tape, take a moment to admire your handiwork.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Drill press makes this job real easy.

Image Notes 1. 2 holes per LED.

step 9: LED Wiring , When inserting the LEDs remember the polarity. You can see the polarity when looking carefully in the gel head of the LED. I oriented the holes so that the even circle LEDs are oriented the same polarity and the odd circles are in reversed polarity. Consider the inner circle as even. I put a small piece of tubing on each leg to raise the LED off the board so it could later be adjusted for focal point alignment. You could also use tiny beads or even small bits of wire insulation too. Manage to get a good picture of the wiring job so you can get an idea from the pix and from the Dave Johnson strip light, just think round instead of straight. Most of the solder connections can be done using the LED leads (use extra bare wire as required). Finish the wiring with two wire pigtails as shown. This makes for easier testing and assembly. Use the duct tape to cover the wiring on the back of the donut. (You may want to jump ahead at this point and test the wiring. Remember; do not just connect 120Vac to the pigtails, as the circuit also requires the capacitor and resistor. Instead temporarily connect to the upper lamp head unit to test.)

Image Notes 1. Look here and you'll see the polarity. 2. If you choose the drill bit right the LED will only go in this far.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Small tubing standoffs. 2. See the polarity?

Image Notes 1. These cross links are shown in the schematic but are not on the earlier strip light picture. Image Notes 1. Attach pigtails.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Insulate the wiring from the metal lamp head. I used duck tape.

step 10: Assembling the lamp head unit , Crimp-connect the LED lamp assembly pigtail wires to the black and white wires available in the Lamp Head unit. Here is a great time to test to see if proceeding would be a waste of time. Plug in and turn on to see that the LEDs light. Yehaw! Then unplug again to continue. Reassemble the lamp head unit but do not install the flimsy plastic light diffuser shell yet. I used the original florescent lamp holding clips modified a bit, see pix, because these clips also hold in the glass lens, so why reinvent the wheel. I found no need to rebalance the weight of the upper lamp unit to compensate the springs as the final weight was about equal enough to original weight head weight. You may need to add a bit of weight, or not.

Image Notes 1. AC Powered White LED Circular Magnifier Work Lamp

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

step 11: Power On , Stand back, plug it in and flip the switch! Mine worked on first try, of course, and so should yours! Shine your new light on a blank area at a good working focal distance. Final tune the LEDs individually to work out dark spots etc. The main pix shows mine before and after tuning the LEDs. You will notice how it seems there is less light output than the florescent lamp. This is because the LEDs are focused through the gel head that directs the light specifically to your working area rather than everywhere else. That is exactly what we desire in a magnifier lamp. So it does really work. Lets compare. Philips Circline 8 inch General Purpose Color = Cool-White Light Color Temperature = 4100K Dispersion Pattern = 360 degrees Expected Life = 10,000 (4 years based on 6 hour days) Energy Used = 22 watts Light Output = 1050 lumens LED Replacement Light, Instuctables Project Color = a Cool White Light Color Temperature = 7000K Dispersion Pattern = 12 degrees Expected Life = 1000,000 hours Energy Used = about 4.2 watts Light Output = 610 lux at 16 inches 1340 lux at 12 inches 1900 lux at 10 inches 2700 lux at 8 inches 2270 lux at 6 inches 940 lux at 4 inches Ok, so I will not bother to go into all the difficult mathematical details about this (I'd have to understand them first). Basically lumens stated on the flourescent light are dispersed everywhere while the LEDs have a narrow light beam so a comparison is difficult. The lux measurements above were taken with an LX1010B Digital Lux Meter. As a comparison my bench-top measures 490 lux and is illuminated by 2x 48 inch 40 watt florescent tubes suspended 5 feet above.

Image Notes 1. This pix looking through lens prior to fine tuning the LEDs.

Image Notes 1. This pix looking through lens after fine tuning the LEDs.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Image Notes 1. Finished tuning. Great lighting. With light diffuser attached.

step 12: There you have it! , Call over everyone you know, and even some you do not. Plan your bragging plan while you await their arrival. Because unless they build one, they will never get one. Enjoy. by Egon Pavlis Biomedtronix www . Biomedtronix . ca

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

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Comments 23 comments Add Comment

bilti says:

Sep 19, 2008. 9:50 AM REPLY

Is it possible to use a bridge rectifier? the blinking at 25 rate is not confortable

soktha says:

Jul 13, 2008. 4:29 AM REPLY

I've just followed the diagram designed by David A. Johnson and adapted to 220 vac ( France ). the capacitor is not polarized ( 400V capacitor, 0.22uf ) the resistor is a metal oxyd ( 1K 1W ). also for the second experimentation, i've put 72 Leds ( always followed the provided diagram ) the lamp works fine. diagram and detail : http://www.discovercircuits.com/H-Corner/AC-Powered.htm Again, thanks to David A. Johnson. Soktha

bilti says:

Mar 22, 2008. 11:29 PM REPLY

Hello, How many led`s I can use if I have 220V?

Derin says:

Jul 3, 2008. 2:07 AM REPLY

double of 110V

arcticpenguin says:

Mar 23, 2008. 2:19 PM REPLY I have no experience with 220V here. Having said that I refer you to the information in step 2 where I quote the article that supplied the schematic and circuit description. My understanding that within reason there is no limit as we are powering by constant current. In paragraph 3 of step 2 I provide a link using the words "DiscoverCircuits". Just click there and you can possibly email Dave Johnson himself for help.

Derin says:

Jun 28, 2008. 12:36 PM REPLY

the same cap system is also used inside a hairdryer since there is a 12VDC motor inside

skrubol says:

Jun 13, 2008. 11:37 AM REPLY Unless you're trying to limit non-LED components, a bridge rectifier would make for a better operating circuit (convert to DC.) Run the AC through the bridge, put the cap in parallel with the rectifier output, and the resistor in series (current limiter, necessary for LED's.) You could also put an inductor in series with the input of the rectifier to limit the current instead of the resistor (more efficient,) but the math is more of a pain, and I think it needs to be a very large value inductor (which means the inductor is large and expensive... On second thought, just stick with the resistor.)

July Dragon says:

Apr 2, 2008. 11:29 PM REPLY

Great work! But have you try leaving the lighting ON for a long time without switching it OFF and see that all the LEDs are working fine? Thanks.

lrooff says:

Mar 14, 2008. 7:39 AM REPLY It's a neat project and should reduce the use of electricity for the lamp, but as far as keeping mercury out of the environment, it's likely to have the opposite effect for the simple reason that the florescent bulb which would otherwise remain in use in the lamp for several years is now going to wind up in the dump right away.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

arcticpenguin says:

Mar 14, 2008. 10:51 AM REPLY

I'm not advocating getting rid of a fluorescent lamp to place LED's but only when one has to be replaced anyway. Everyone should be aware by now that fluorescent lamps are mercury safe as long as they are not broken. Once it burns out it must be treated as hazardous waste and needs to be taken to a handling facility. It is unlikely that most people will do this though as they don't do it for fluorescent stick lamps yet.

Derin says:

Mar 21, 2008. 12:10 PM REPLY

im sorry but we don't have handling facilities here

ScottSEA says:

Mar 15, 2008. 2:41 PM REPLY

An excellent and useful instructable. Well done.

Stokes says:

Mar 13, 2008. 2:11 PM REPLY

The schematic shows a polarized capacitor... is that right?

arcticpenguin says:

Mar 13, 2008. 4:33 PM REPLY I see what you mean. Though, in my day this was the symbol for any capacitor and there would be a dot or small plus sign to label polarity. http://library.thinkquest.org/10784/circuit_symbols.html This link shows the symbols I'm used to as far as capacitors go anyway. Because of the written circuit description that I found I went with a non-electrolytic. I believe it is because an electrolytic would not work properly as the current limiting while on AC. Thanks

Stokes says:

Mar 13, 2008. 9:13 PM REPLY I stand corrected. Knowing that the symbol with one curved end isn't necessarily polarized makes some other schematics I've seen make a lot more sense. I think I have all the parts sitting around to build a small version of one of these; I'll have to take a look!

offlogic says:

Mar 12, 2008. 6:12 PM REPLY Loved your Instructable! I have two such fluorescent magnifiers at home, and a number of them at work. The work lamps are all "O.C. White" brand, which are fine lamps no mistake there, but they use a custom lamp size with a list price of $30 to $40 each. Outrageous! Next time we need a new "bulb" I'll whip out an LED array like the one you speak of....

GorillazMiko says:

Mar 11, 2008. 3:53 PM REPLY Wow, great job! I really want one of these in my rooms, but that would probably be a bit too hard for me to make. Still, great job.

Spokehedz says:

Mar 11, 2008. 1:35 PM REPLY

have you checked out some of the constant current LED sources on DealExtreme lately? They seem like an ideal part for this project. Plus, you could wire the LED's in series, so you could save on a bunch of wiring--and you would be able to use the high-brightness Luxeon LED's. Instead of hundreds of LED's, you just need one. http://www.dealextreme.com/details.dx/sku.11077 I was thinking about making my own lamp from one of these. Replace a Halogen light with an LED.

arcticpenguin says:

Mar 11, 2008. 3:47 PM REPLY

Interesting item for sure. I wonder what is actually inside the $9.15 white box. The circuit I'm using is a simple capacitor to limit current to about 20mA. Change the value of the capacitor will change the current limited. Cost about $2. Then I looked up the Luxeon LEDs you mention and the largest ring they have is only 5.5 inches diameter, much smaller than the 8 inch I required. That lists for $160. Even the cost of the pucks are $17 to $20 each. For the cost of 2 pucks I can buy a used lamp and totally convert it. For the cost of a ring, even though it is too small, I could by 2 new circular Magnifier lamps, more if I go to ebay. While it is a nice idea it's just too darn expensive for my tastes. Maybe worth it for a professional technical application but not for the hobby. An LED is a focused light rather than a halogen, fluorescent and incandescent. You'll find for most applications you'll need the 360 degree dispersion.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

Thanks

LinuxH4x0r says:

Mar 11, 2008. 6:12 AM REPLY

Great Idea! Much better than those florescent tubes. +1

arcticpenguin says:

Mar 11, 2008. 7:40 AM REPLY Maybe not as cheap initially but when you consider decontaminating a mercury spill? Definately more fun though. I figure eventually something like this will be commercially available, but until then. Thanks.

rgbphil says:

Mar 10, 2008. 9:57 PM REPLY

Great idea, I've just gone through replacing my ring flouro on my own magnifier lamp. Couple of points though....I presume you meant your configuration is 2 sets of 30 LEDs, in parrallel with each set consisting of 2 strings of 15 LEDs in series?? I'm trying to figure out how you could get 60 LEDs in series going on 120VAC, the combined forward voltage for 60LEDs would be around 192V (assuming a forward voltage of 3.2V per LED). Could you add a cct diagram showing the electrical connections? Concerning the 120VAC supply, I'd recommend another warning that when adjusting the beam of the LEDs, that the ring will be at mains voltage.

arcticpenguin says:

Mar 11, 2008. 7:34 AM REPLY

rgbphil, Thanks for your comments. At the bottom of Step 2 I've included a pdf file that is the schematics. I tried doing up a pix of it but the text is not clear enough. Once you see the pdf you'll see the circuit is rather simple. That with article I quoted will explain the theory better. When adjusting the beam of LEDs the ring is at Mains voltage but no exposed metal is present, it is all taped and insulated behind the whiteboard. Thanks

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/