this was supposed to be my entry into the awesome contest Old Lumens organised, but life got in the way. However, I still need it as I have a bunch of car work coming up and I gave my old headlamp to a friend. Although my old one was much better than holding a torch in my mouth, it had a bunch of flaws. The P4 was pretty cool with crappy colour rendering and was pretty spotty. The low wasn't low enough and had visible PWM when looking at rotating parts. Finally, and the thing that pissed me off the most, the 3xAAA battery box at the back was modded with a single 18650 holder (much better than constantly replacing alkalines) which was great for battery life but constantly got in the way when I was lying on my back trying to find or fix something under the car.
Aim - high CRI wide beam headlamp, with everything on the front of the headband and build in USB charging. Has to be robust and comfortable as it's going to get a lot of use.
First step was modding the USB>li-ion charging board to fit inside my 1in.sq. alu tubing housing.
stock (you can get 'em off eBay for $2-3)
I've used a bunch of these and in previous builds I've cut the USB connector end of and soldered wires between the two halves (v. fiddly). Being lazy and short of time, I wondered if instead I could just cut the board enough to bend it but leave the +ve and -ve traces intact.
bent. black tape is there to isolate a capacitor underneath the connector when it's bent
end caps cut for the switch and charger. Tapped for 4-40 screws
switch and charger board 5min epoxied in place. Driver is a 1.4A DrJones mobydrv. It was originally meant to be a 1A lupodrv board, then I swapped the lupodrv MCU to a 2A board and this one ended up on a 2A board, from which I removed the 2 chips on the back. I still don't remember why I did it that way, but I'll rarely use it on high anyway.
ran out of time last night to wire up the battery, so I'll hopefully do that tonight. Then I can measure up the combined width and cut the housing tube to fit. After that I need to cut and bend a bit of tube to cover the LED and optic and a u-shaped piece to bolt it to the Magicshine headband ($3.50). Oh, and stick a bit of innertube over the switch for some water/dust resistance. Charger port will get a rubber USB plug and the hole (to see the charge state LEDs) has already been filled with 5min epoxy.
thanks! I’ve never done an “in progress” build thread before, so hopefully it’ll help me keep up the momentum. I’ve been planning this for over 6mths, so overdue stuff will always get done, eventually
no more progress. I had the “pleasure” of spending last night replacing a CV joint boot on the car so work on the headlamp (which I sorely missed last night) will hopefully resume tonight. Unless the new rear springs arrive today that is…
finally got the battery wired up and couldn't help but hook up the LED (Nichia 219 from Illumination Supply on an alu Sinkpad sample) to see if it worked. Always the scariest part of a build, but it lives!
close up of the wiring
I'm really digging the electronic switch as it's so easy to use and saves at least 1cm compared to a judco clickie.
If it doesn't take to long to change the springs on my car tonight I'll start on the housing. The main tube won't take long, but the optic cover will be a bit fiddlier.
thanks, I’m very excited about finishing this light and it’ll get a lot of use. One benefit to taking so long to build things is that I get to ruminate on problems/ features, which is how I came up with the idea to slice the charger. That and soldering to the +ve USB port trace is a royal PITA
I’ll warn you, the housing isn’t going to be terribly attractive! The optic/ LED cover will be removeable so that I can swap out the LED or optic in the future, plus it’ll add some surface area for cooling.
blushes er, I wouldn’t go that far. I am a very good tinkerer though This isn’t much different to other builds I’ve done, so it doesn’t feel that innovative to me. I’m just looking forward to having my headlamp exactly as I want it - when you can spend a whole day with your head stuck in an engine bay, little niggles can become very annoying.
Intriguing
One question: if the battery stays connected to a charger all the time, won’t there be some voltage leaking back to charger?
Like those cheap chargers, not even plugged in mains but if you insert the battery it will lit up green led!
I have to admit, that making this with hand tools and your skills, took you much less effort, than it would take me, machining it out of a solid piece of material. So Matt, again, you deserve a slap in your face, for making us so uncreative and lazy with all the equipment we have access to. As alway, congrats mate. Can’t wait to see the finished product.
I don’t think that happens, although I haven’t done anything to test it. If it does occur it would have to be a pretty tiny leak as some of the lights I have with these chargers (work light that got thoroughly smacked by a drive axle Tuesday night, commuter bike light etc) don’t get used for up to several months depending on the time of year and they still have a decent charge when I go to use them. Neither status LED is lit when not charging.
ouch, that slap hurt! I’d love to machine a light like this, but that 1in.sq. tubing is so convenient - the battery, LED, driver and (most importantly) charger board all fit easily and the material is really easy to cut and finish. I think this is my 11th or so alu tubing light, so I’ve got all the techniques down pat. The slightly thicker wall tubing is better as it’s easier to tap, but the thin wall stuff I have now is lighter and I got 2ft more of it for $5 less than the other stuff
Remember, when you got that lathe, I told you to ditch that tubing? I’m really glad you didn’t. And that slap wasn’t ment to hurt at all, I’m just jellaous I don’t have any spare to time to make stuff. I still have at least three unfinished projects that I’m not likely to finish. Keep it up mate.
you know what, I do remember that now I know what you mean about finding the time, it’s never easy and my project list gets added to quicker than things get taken off it. Still, when you do find the time, the things you make are even more precious!
BTW, I haven’t forgotten the lathe. I recently bought a 4 jaw independent chuck for it, which has the same thread diameter and pitch as the original, so I can swap between them easily. 2 more things need doing, making a fiber optic work light and finishing the milling attachment. Then I can start on my new helmet light - hopefully it’ll be done before the end of the year, although I won’t be able to test any thermal monitoring until spring as some of my winter night rides hit –15C
Nice work. I have a question to ask is that the charger, the battery and the driver seem to be always connected. In case the driver is accidentally pushed on when charging, will this damage the charging IC TP4056 ?
The datasheet claims the drain is 2uA. You can’t actually trust the datasheet on chinese chips though (its claimed charge profile doesn’t match reality for one). But even if its not as low as 2uA it should still be small enough.
