Step 4: Assembling the electronics box

Now for the LED driving circuit.  The aluminum box is one I picked up at Fry's; just about anything the right size will do.

Drill some holes on the end, clean up the sharp edges, and insert some rubber grommets.  Insert the AC power cable, tie a knot in it to prevent it from slipping, and solder it to the circuit board.  Make sure that the live and neutral wires are hooked to the right place.  I had to check which wire was which on my multimeter--the "fat" prong on the plug side goes to neutral while the thin prong goes to hot/live.  Also make sure to get a very solid soldered connection--you don't want this coming undone!  The GFCI will help if anything goes seriously wrong, but you don't want to get to that point.

You'll need three wires for the other side--one for ground, one for LED positive, and one for the fan positive.  Insert the wires through the grommet and tie another knot.

I don't have a picture here, but for the interior connection you'll want ground to go to the black wire from the board, of course, as well as LED positive to red.  For the fan wire (yellow, here), you'll want to tie it to a reasonably beefy resistor (2 watt, 470 ohm is good).  The other side of the resistor goes to the normal positive lead.  Make sure to shrink-wrap everything.

When you finally test this, make sure to wear safety glasses the first time and stand back a ways.  Nothing should go wrong if you've been careful, but in the worst case a component could explode and send shrapnel out.  Be careful, and as before ASK FOR HELP if you aren't sure about the wiring.  AC wall power is nothing to play around with.

I used Kapton double-sided tape to attach the board to the case, but you may want something more robust.  The board had a large metal plate on the bottom that you can tap and screw into if you like.  I may just go that myself, but for now the tape is sufficient (Kapton is strong and heat-resistant).

By the way, this circuit board handles any input voltage from 85 to 265, so it will work equally well anywhere in the world if you have the right plug.
<p>i have an old 36 volt Li-ion drill battery, which does fluctuate a bit sometimes up to 40v on a full charge. Do you think it would power the led or fry it? the battery seems to only be able to power 2 12v car bulbs (incandescence, xenon etc). Not sure, still a little iffy on my electronic skills and my multi reader does not want to give me any info except voltage. It can only read up to 200ma so im assuming its higher than that.</p>
You're into your task lighting. I don't want to sound mean or anything but the most likely reason you snapped a bit is because the drill bit walked on you when you started it. Lubricant had nothing to do with it. You have to be doing super high speed production for lubrication to be a factor with aluminum. If you insist on using your DRO method use a center bit before you use a little twist drill. Better yet just use transfer punches and skip all of that measuring entirely. But then don't drill out on the mill with a vise bolted down. Small twist drills should be run into divots or they'll walk, flex, and snap. Not every time, but enough that common practice is to punch the work before drilling it.
Don't worry at all about &quot;sounding mean&quot;; I'm a beginning machinist and I know it.<br> <br> However, I don't believe that bit wandering was the problem here.&nbsp; That was in fact my first theory behind the breakage (even though I've never had a problem before on a very smooth, freshly face-milled surface), and so on the next hole I used a center bit (actually, a really beefy sharp-tipped chamfering mill).&nbsp; I then drilled down just a little ways and inspected the bit before going further.&nbsp; The aluminum had completely galled to the grooves, and I had to dig it out with a sharp object.<br> <br> A little spritz of lubricant solved the problem completely, giving me nicely-shaped chips instead of long strings that would gall to the bit deep inside the cut.&nbsp; The last two holes I stopped using the center drill, and I had no problems at all.<br> <br> You're probably right that I should always punch or center drill first, but the fact is that I'm lazy :-).&nbsp; That said, I've been meaning to pick up a set of shorty bits, which would also improve matters.&nbsp;
In light of the new information I wonder if you were running high enough RPM? Aluminum surface speed is high, about 300 surface feet per minute. Also, you know you are supposed to raise the bit out of the hole often to chuck the chips don't you? You can't expect the twist helix to completely clear the hole for you. You have to start raising after you've gone about the depth of the diameter you're drilling.<br> <br> I have seen materials stick to bits working it though. That can be because of poor tool finish. In which case then you would have to use some kind of a coating to overcome the deficiency, or buy better bits.<br> <br> For laughs I figured out what RPM you should have been running for the size hole it looks like you drilled and no milling machine can go that fast. It is slightly over 9,000 RPM. If you were going that fast the chips probably would have flown off the bit don't you think?<br> <br> I don't know what the top speed of the machine you were using is but I'd be surprised if it is over 4,500 RPM so being as you could only run about half of the speed you should you would have to adjust your technique some.<br> <br> I just got done running some little jobs here where I had to center drill start a number of holes. It is a pain. Works though. I made bearings brackets and lead screw lock collars for a CNC machine I'm making. The machine has 2 sets of double lead screws too so it added up to 8 of each. On the bearing brackets I drilled for 3 8-32 set screws a piece too. Oh, and I made a couple of extras in case I messed one up (I didn't but I felt better setting up different operations having made extras). So for the brackets alone I had to do about 30 chuck changes just for the center drill. Then another 30 to mount the bits. I'm striving to be lazy, so far it hasn't worked out for me yet though.<br> <br> P.S. Being lazy always ends up costing me extra work, materials, tools, time, etc. machining.
You're probably right about the spindle speed; I was at about 3k (machine didn't go much higher), and I think your 9k figure is the right ballpark. <br> <br>I was using peck drilling but a single diameter seems like overkill; I was going about 3 diameters at a time. Maybe shorter pecks would have prevented the break, but adding lube solved the problem equally well (this is starting to sound dirty...). The chips were actually being cleared well enough that I doubt I needed to peck drill at all. <br> <br>Sounds like a cool project you've got going. I have a mini mill at home that I've thought about converting to CNC. That's kinda on hold since TechShop has a nice Tormach CNC that's better than any home conversion that I could do.
I clear chips to stop birds nests from forming as much as for any other reason. There are too many variables to make any specific statements as to when chips should be cleared other than they need to be.<br> <br> As far as surface speeds go they are all known at this point. I use variations of this formula<br> <br> SFPM = PI * Dia. * RPM / 12<br> <br> 294.5 = 3.1415927 * 0.125 * 9000 / 12<br> <br> Aluminum working surface speed is between 250-300 SFPM but small diameter tools should be run faster to stress them less. The additional speed translates into less torque on the tool.<br> <br> There is a metric analogue to this formula but I am not very familiar with it. Whenever I need to work in metric units I convert to imperial measurements.<br> <br> Speeds and feeds is intermediate machining magic so it pays to become familiar with the topic as best as you can. For aluminum it is less important, when you work with harder materials like steel it becomes more critical. Perhaps this is because the relative hardness of your tools, and materials gets closer to one and another. Then you must rely less on sheer brute force, and more on finesse to get the job done.<br> <br> P.S. I didn't bother to look up what drill was used for your tap but just guessed it was about an eighth of an inch (0.125). I was only looking for a ballpark figure and knew you likely weren't even close. Calculating machining speeds is one of those rare places where math is really cool. heh
I did a similar setup for a SAD Light. I have problem with the power driver or the led array. It seems to be overheating after some times, only the strip of leds in the middle of the array stay lit. <br>
What kind of heatsink setup did you use? A good rule of thumb is that the LED should stay cool enough to touch without burning your finger. If that's not happening, you need a bigger heatsink or one that's in better thermal contact with the LED. A very smooth surface, thermal paste, and a reasonably high clamping force are important.
I checked a local supplier (Germany), and while they sell 50W LEDs, they cost 80&euro; and above (~100$)... I wonder where the price difference comes from...
Ebay is your friend, I found a supplier once that offered 5 of these 50 watt ones for about $40-50.
Interresting. I wonder whether their quality would be an issue, i.e. whether you would notice the extra money spent or not... At that price, I'd call it a bargain...
I'm not sure. Your local source may be higher quality, but the $16 unit I used seems perfectly good for my purposes. My source has even larger emitters but they start at $66 for 100W, so the 50W version is the best deal.
You sir, are improbably talented at naming projects. Nice work.

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