The ultimate Be-Seen bicycle light build - P60 drop-in for 28mm aspheric lens.
NOTICE: ...this is NOT for you thrower fans; it is NOT for those who like absolute brightness; this mod IS for those who want a nice bike light with a wide dispersion beam that won't blind the very people you want to see you. These are front or rear Be-Seen lights; not specifically lights for seeing, although this does put out good light. This is a fixed unfocused solution with a wide variety of modes specific for your needs of cyclists that want to be seen from wide angles.
History: ... I've been using UltraOK 18650 blinky zoom lights for the past 3 years to be seen on my bike. I have had very positive comments about the lights, and the behavior of the cars in my vicinity has been more favorable than I could have ever expected.
Choices: ...a lot of time has been spent deciding how to get longer runtimes; lower flash rates; an appropriate emitter for the build; and the appropriate light output. I chose the XM-L emitter for the low Vf requirement at lower currents. The XM-L can run at 1A down to under 3V; the driver choice was the 16-mode NANJG 101-AK driver because of the "police" and 1hz strobes. There are other nice modes here but these are fairly unique and easy to dial out if you don't want them. I also choose a 1A drive current to the XM-L as this is sufficient for the purpose of this light. This is also the current the UltraOK zoomies run at into XR-E Q5 emitters. This should make this light a bit brighter than the Q5's but provide consistent light output throughout the battery life.
The host I chose was the UltraFire 504B due to the 28mm lens and the robust, and replaceable tail switch. This is also a P60 host which was probably the easiest module to modify for my purposes. The 28mm aspheric lens came from Deal Extreme and the red film for the tail light version came from ebay. This essay is about the P60 drop-in build since any P60 host can be converted if you have the aspheric lens to fit it.
You have to admit, this is an impressive light:
Silver UltraFire 504B w/ red aspheric
1st I needed to know where to place the emitter. The actual position of the yellow stuff in relation to the lens. Turns out that the physical center of the 28mm optic is only about 5mm from the flat surface of the lens; not where one would think when you get an actual optical focus which is close the where the P60 would normally put the emitter. A previous experiment had given me some insight to the matter. But this CAD work was an eye-opening exercise. In this case, the die is at the physical center of the lens' sphere.
CAD study of the optics
Some machine work was required to the pill, the reflector, and a custom pedestal for the emitter. The pill was machined with a vent hole; The driver pocket was deepened for the NANJG drivers which are 1.6mm thick; the emitter "floor" was smoothed and flattened; and the ID of the emitter pocket was opened up significantly.
Pill being machined on the mini-lathe
An old smooth reflector was machined out to accept the pedestal, and the pedestal was machined from aluminum to drop-in in the pill and held by the reflector. You will see a shoulder on the pedestal and a pair of holes through the pedestal all the way through the pill. These holes are for the wires. The emitter side of the holes were also tapped to #2-56 so the emitter could be held for gluing. The hole in the center is there simply because that was what I found at ACE h/w. A future post will detail the pedestal for those wanting to duplicate the work.
View 1 of the modified parts
View 2 of the modified parts
It took me a while to figure this out but I decided that gluing the parts with Arctic Silver epoxy was the best way to go for holding the parts. I glued the pedestal in the pill aligning it with the drill bit and clamping the pedestal with the modified reflector.
Pedestal being glued into the pill
Making sure the wire holes lined up with the pill
At the same time, the emitter was glued to the pedestal being very careful not to get glue in the threads. This is the reason for the earlier breather hole in the pill so there was no trapped air space that would pop off the emitter.
The emitter with glue sitting on the pedestal
I used a Mylar washer with a pair of holes and some brass #2-56 screws to clamp the emitter star down to the pedestal while the thermal epoxy cured.
Emitter clamped to pedestal
Once the thermal epoxy cured, the Mylar washer and the screws are removed.
Emitter epoxied to pedestal
I placed the aspheric lens on the pill to check the ~1mm clearance. The 504B host has an ~1.8mm lip for a total of around 3mm clearance to the dome of the XM-L.
Emitter through aspheric lens
Once again I choose to use solid core wire; 22awg. I also opted for the Teflon coating that I stripped off the Illumination Supply 24awg stranded wire. This was a tight fit, but the high temperature that Teflon can take when soldering the wire made the effort well worth it. I wish I had some red and black, but this works good.
22awg solid wire and salvaged Teflon sleeves
The new NANJG 101-AK driver was received from KaiDomain in record time. This driver looks as good as any of the previous drivers I've received on this brand. I had little concern about DOA so I just went for the build.
NANJG driver and wires
A quick break and grind of the tabs on the driver made it ready to test fit into the pill. These often come a bit large but I had already accounted for this when machining the pill. Then a small twist at the end of the wire and the wires were quickly soldered to the driver. The insulation slid down to the solder joint easily. The spring was also soldered to the driver.
Wires and spring soldered to the driver
The insulation was trimmed to about 1/8" past the emitter star. The copper tails were left long. The driver was dropped in place making sure the driver "+" was to the "+" side of the emitter! ...and the driver was soldered to the pill with the aid of some extra wire to bridge the gap.
Driver soldered to pill
Now it is time to check the business side of the build. The insulation is well past the emitter star...
Emitter w/ wires ready for prep
Wires trimmed and formed ready to solder...
Wires dressed for soldering
Wires soldered, flux cleaned, ...fingers crossed.
Wires soldered to emitter
Moment of truth. Add reflector, large spring and check the emitter with the diode check function of the DVM; check the battery connections for shorts with the ohmmeter... all good.
Pedestal P60
Things look pretty funny through an aspheric lens. The emitter looks like it is as deep as a P60 with a normal lens. It really is only 3mm below the lens. The emitter itself looks about 5 times as tall... and everything is bigger. The lens has the red Rubylith in place making this an awesome red flooder.
"pulled" emitter
"zoom!"
...and a parting shot.
Stay tuned for the details of the pedestal and pill/reflector mod.
