It’s possible to get a dpst swtich, so you have one pole that “bootstraps” the MCU by turning on a transistor, and then you have the other that is used purely for click detection. It may even be possible to do this on a spst switch with some electronics trickery. When the MCU detects i’s below X volts, it sets the pin holding the transistor to “off” and the whole thing goes totally dark. No power until the button is clicked again.
Hardware wise, it would be best to use a mosfet to minimize quiescent current, and make sure to use very high value resistors for the “on” signal to the mosfet. Given the relatively high capacitance of the mosfet gate, you might even be able to get away with putting a capacitor on the line to hold it high, and just give it a periodic pulse to maintain voltage when in sleep, if you desired to keep the MCU running.
Have you measured the power used by the Q8 driver during standby, or after LVP activates?
In stock form, with the button LED off, standby drain is about 0.02 or 0.03 mA. Or after reflashing it with different fuse values, it’s even lower. If I recall correctly, it was something like 0.00002 mA. And with four cells, divide all these values by four. This makes the standby power virtually indistinguishable from zero, because it’s lower than the cell’s self-discharge rate. With the right fuse values and with the button LED off, I’ve found that I can actually take the battery out for a few minutes without making the MCU shut down. And it can still wake up on button press.
Atmel calls this “picopower”. It makes standby mode use such a small amount of power that it’s not necessary to design in clever power-disconnect circuits.
Yeah, I’m not suggesting it’s necessary, just providing input. I think it might be more relevant given a driver that couln’t use the super-low modes on the MCU or for a non LiIon battery. (AA Emergency light, for example).
That’s a super neat anecdote on pulling the cells!
BTW, I’ve been studying the FSM code for a potential MCU port, well done on the organization! I’m still picking up C syntax, but overall it’s very readable for me.
I wonder if there is a market for protected cells that only have LVP rather than LVP and over-current.
Oh yeah, it slipped my mind that USB is only 10 watt (2A@5v) at most. This would make it very slow if you were charging 3 or 4 batteries.
USB-C might be the better choice. A few flashlights already use this. It’s capable of 60W (3A@20v). So maybe the internal charge rates could be 1A to 1.5A per cell. That would greatly reduce charge time.
One problem I see with built in charging in general is that the Q8 can run on 1, 2, 3 or 4 cells. If the charging circuit delivers 4A@5v (1A for each of the 4 batteries) and you happen to be running only 1 battery in it, all 4A will go to the single cell and lead to disaster.
The jankiest Ukrainian? MCU in existence that they used in the MF02s. If I can find the time, it will be less of a “port” and more of a controlled demolition onto a new chip. Basically it would involve taking any of the references to atmel libraries plus any of the assumptions about timers and subbing in a compatibility library or something. I’ve posted a few findings in maukka’s MF02s review thread. Ultimately I don’t have a lot of hope, but it would be nice to do, as the driver is a quad channel boost driver running the XHP70.2 at 12v.
Actually USB Power Delivery (which uses Type C connector) allows for 100W, 20V 5A.
There are laptops (and adapters) on the market already which do (from memory) 95W.
Yeah, but I’m talking about the more common USB-C. 20-30 watts seems the most a charger would need.
I still don’t see it working well on a multi cell flashlight unless you were to limit it to 5 watts total. That’s 0.25A to each of 4 cells and a very slow charge. I think that’s the real issue.
Has any parallel battery light had a charger circuit built in? If so, I wonder how they dealt with this issue.
I remember Haikelite did a charger cap that went on a battery tube of 4 cells. It acted as a charger, power bank and mini flashlight. I never got any details on how it worked, though.
FWIW, the HI version should give a more consistent tint without the usual Cree rainbow. And if you want it less throwy, DC-Fix is cheap. Together, they should make for a very nice-looking beam.
I’m more interested in output levels. I’ll probably have the weakest output Q8 of anybody. 4000 lumen maybe. I want 6000, but no way with the HI version.
Nope. You know the big golden light in BLF’s front-page logo? It’s that light. An original Skyray King, modded with a BLF driver and some other things. Currently it has a prototype Q8 driver in it, and it’s what I used for part of FSM’s development.
Oooh I had completely forgotten about the original inspiration of the BLF Q8.
Very nice light BTW. Also, very smart idea to combine multi-tint/CCT LEDs. Maybe I should do that for my bathroom with some high CRI LEDs lol. The fluorescent lamp currently in makes everything look green.
Because of this, I feel like I look much worse during the evening than during the morning when there’s abundant sunlight.
Have you ever experimented with multi-tint high CRI LED strips setup BTW? I don’t know if it’s a false memory or not, but I have seen you write about it on BLF. Maybe I’m just hallucinating or something.
