You are totally right about the 47uF, missing ceramic resistor (near the red wire) and "01D" resistor, i just updated the schematic.
It took me too much time to reverse engineer the schematic because i was looking for a current drive like the PAM2803 and couldn't have it to fit what was on the board ;-) and i was expecting an Attiny too :-(
From what i have seen, without a current mode drive (a higher voltage with a higher value serial resistor is a decent current drive at low power) the led output might change pretty much from one led to the other even in the same batch (U/I curve irregularity) and is more temperature sensitive but that is certainly not a real concern for that kind of use :-)
The parallel 8205S and rather small inductor certainly help its current capabilities but efficiency probably sucks. I’m a bit skeptical about that “800mA”.
I’d really love to see an output/runtime graph on High…
Nice find !! I have watched many small boost IC datasheets but couldn't find one that was totally fiting !
I am somewhat short of time at work right now but i hope to be able to take this driver to the bench soon and see what it can do
So now we only miss the MCU ... i have seen that "gnd at pin 8" on some cheap driver's picture already but don't know that kind of IC well enough to guess what it could be. Idea anyone ?
Could be one of the countless 8-bitters that Holtek makes. Cheap and generic. I’ve found quite a few that have GND on pin8 but pin3 would be reset I assume… no luck so far. Maybe a PIC12Fxxx or a clone, VDD and GND match too.
Does it really matter though? It’s going to be far easier to shoehorn in an Attiny.
Thumbs up for a link to the boost controller, I’m pretty sure I hadn’t seen that one.
I’m interested to see some performance values of the driver. I’ll buy me a pair of T2 at Fasttech, 12.47$ –5% BLF code = 11.85$ ist the best offer around. Banggood, Gearbest, all more expensive despite some code offers.
In the meantime, I need 2 measurements: The outer diameter of the driver (roughly to 1/10 of a mm) and the inner diameter of the retaining ring.
Much obliged.
I’m already tweaking my Oshpark boost drivers for the T2, I’m pretty sure I’ll build them myself as I’m not that fond of shoehorning MCUs… any more
Trying to measure the current drained from the battery whith an ampmeter did some very weird things at max brightness. I guess that the voltage loss in the measurement shunt was too high and made the driver to enter a very fast ON-OFF loop.
So i measured the voltage across a (very) low R shunt and got 3A max with a freshly charged eneloop.
Changed the 0.2 ohms limiting resistor in the driver of a second T2 (stupid me who didn't think of measuring this one before modification for reference !) for a 0.5 ohms, got about 2A max and then 1 ohm wich was 1A max
Lux measurments are from a calibrated Minolta T-10A using a 20cm polystyrene foam ball setup according to Djozz's "fast and cheap integrating sphere". As i don't have a calibrating light for now i have no good way to convert from lux to lumen but a Convoy S2+ with xm-l2 T6-4C at 1.4A (4*7135) in mid (40%) mode (should be about 200lm ?) reads 924 lux with the same setup.
Get the T2 from their Taobao store instead. 淘宝网 - 淘!我喜欢
Taobao Description:
(2) Low voltage protection: When the battery voltage is between 2.9 and 3.1V, the flashlight will alarm, showing a weak brightness with 2 flashes per second.
(3) Reverse battery protection: the battery will not light up, but there will be no abnormalities, no need to worry about burning the battery or circuit
It has low voltage protection and reverse battery protection while the one on Aliexpress store doesn’t have them. Pretty disappointing as the Aliexpress store is direct from Convoy. Anyone contacted Simon about this?
Thanks, but nope, don’t intend on getting it from TaoBao, even because I don’t have 14500 cells to toss in it so the LVP is moot and I don’t think they even ship to my country. If anything, I’ll wait for Simon to have his stock updated/upgraded.
Really nice look and feel. I’m a sucker for the S2+, and this is absolutely its little brother.
Greatest asset is that a driver of 17mm does fit. Makes DIY much easier, and the trade-off of a slightly larger diameter is really insignificant.
Lineup:
From left to right
SK68 clone, Ultrafire SK58, Convoy T2 (/w clip + sling), Thorfire TG06, Uniquefire G10, Utorch UT01, Convoy T2, Manker T01, Thrunite Archer 1A
Stock mode spacing is already really good, waaaaaay much better than most, especially the expensive AA lights. But doubleclick-to-strobe and PWM are a downside. Leaves room for improvement.
Got my Convoy T2 last week. Haven’t had much time to play with it. First impression, big and heavy for a AA only
If you like the smaller lights, I recently took delivery of a batch of small Sofirn lights - SF10, SF12, SF14v2.0 & SP10v2.0. The SP10 comes in black, red and blue.
I really like Sofirn lights, but not the AA ones so much.
Speaking of size, their 3 clicky lights (SF10, SF12, SF14) are all larger than the T2.
And the SP10 is a momentary light (that comparison would really be apples and oranges) more in the ballpark of the UT01. I eyed the SP10 for some time, but refrained because of the don’t-drop-it-or-it’s-broken problem. And it’s much more difficult to mod them. Most lights I buy, I see them as hosts, which happen to have stuff inside…
Oh, and color, the Sofirn red is too pink for me. The Convoy red is good. Not as nice as the Maglite red, but good. I’d take blue and green as well…
Sorry to dig up an old thread, but I was poking around about the driver in the T2 and ran across this. Great schematic!
And yeah, that’s PIC-like layout, not compatible with our usual attiny’s. But the new ones (attiny412) would work, as long as you don’t mind the new architecture. The one downside I see… no provision for voltage readings via a voltage divider. And since the voltage coming into the MCU is boosted, internal vref readings are out of the question. So no driver-based LVP? Hmm… at least it’s a 17mm driver.