If you do direct drive with resistors, keep in mind that the calculations above are “ideal”, i.e., they don’t take into account an already-existant resistances like the switch, the body, etc., so, assuming that there are such resistances, and how large they are, if you use the “theoretical” calculations, you’d end up under-driving the LEDs relative to their maximums. From an engineering standpoint, that’s a good thing, but from a hobbyist, or your standpoint, you may want to/prefer to over-drive the LEDs :), so adjust the values as you see fit.
Since a 219 on a well heatsinked sinkpad appear to give maximum output at about 4.3V (and survive 4.7V) I see no problem at all in just going direct drive here with this setup with just 3.8V max per emitter.
3V per might be a little under powered for this fugly monster. 8) Adding another(or more) resistor(s) in parallel will increase the current a bit with each added resistor.
holy cow, that’s not a “little” bit of threaded aluminium, unless that drill pack happens to be one of Ken’s toy batteries!
as for cutting that solid bar of aluminium, good luck I spent about 30min cutting through a bar a bit thinner than that with a jigsaw and metal blade, I shudder to think how long it would have taken by hand.
I put on my man shirt and my man pants. I cursed. I moaned. 14 minutes and one very sore tricep later, I was through. Now I have to make a miter box to cut these @#$! channel bits. (At least the channel will go quick.)
Quick edit: making the miter box was way too time consuming. And the channel went quick but was a complete fail for a few reasons that I’ll detail in the build section above. Back to the metal store…
your man pants must have more space for swinging pendulums as that’s bloody quick. Then again, B&D probably didn’t envisage some muppet cutting through 1x2in alu bar with their jigsaw
Fair dinkum. I’m sure OL did not realize what he would create when he was in the bowels off his shed smoking whatever dreaming up this comp. You guys doing the hand tools build all have one thing happening to you that is common through all the builds. Your all going to have arms on you like Arnold Schwarzenegger. Maybe when this comps over we could have another comp to see who has the biggest biceps off you all. Keep it up guys. I don’t think there will be any machine builds happening as you have put us all to shame.
Wow! That threaded aluminum with the Dewalt battery shown for size reference really put it's size into perspective! Wow! Are you sure this thing will really be portable? Maybe with a dolly to transport it?
Wow! You’ve come along pretty well. I’m a little surprised about that white wall shot… the beam looks not bad for a “tower of power” (you are from CA, right :laughing:!!
I don’t know if the broken hand tap is still bothering you (or if anyone reading this on the “interweb” cares).
I’ve run into similar situations before doing work on cars and completely agree drilling it out is a “no go.” The metal is harder than the vast majority of drill bits. That extreme hardness also makes it brittle so I have had good luck breaking it up with a punch and a ball peen hammer then extracting the pieces.
The traditional way of removing broken taps from aluminum and aluminium is to dissolve them out with nitric acid. The strength of the acid can be important. If it is too strong it passivates the tap material and they won’t dissolve. Too weak and the tap wont dissolve. A little googling should provide some help.
Other people report good results using alum (sold in grocery stores for pickling vegetables). You simmer the part for several hours in an alum solution. Also works for taps in copper/brass that nitric acid will dissolve.