neal has them onstock and ships to the US ;)
Just got the update that they’re in stock at MTN and just ordered. I’m good, thanks all.
Does anyone know what three flashes followed by a step-down means?
I was using the “short tube” (18350) at the standard one-click brightness setting while taking out the garbage. Then it flashed three times and stepped down to a little brighter than moonlight setting. The flashlight wasn’t hot and when I checked the battery, it was at 3.1v. I had be using it for about 40 minutes prior, then took a break with it off for about 15 minutes. Not sure that this signifies.
The battery is getting weak…The high output causes the battery to ‘sag’ and draw it below the cut off for low voltage protection. From the OP:
“This driver also has low-voltage protection. At 3.0V it’ll drop to the lowest level, and at 2.8V it’ll shut itself off as far as possible. It still has a very small amount of parasitic drain though, so don’t leave it in post-LVP mode for months or years at a time. It would be a good idea to change the battery within a few days, or unscrew the tube to cut power.”
Yeah, the shipping from China is painfully slow, I ordered D4/D1s on the 4th and the last info I got just said
“Your item has been processed through a facility in GUANGZHOU EMS, CHINA”
Nothing since
Many thanks! I was going off of the battery specs that it wouldn’t need charging until 2.75V (efest). Good to know that it’s be around 3.0V for this driver.
I usually use the “long” tube that it came with, but I went for a trail run and having it super tiny is convenient while jogging.
Although the driver puts LVP at 2.8V to 3.0V, the reason it does that is because of how the cell behaves. With li-ion cells, there is usually no point in trying to run at lower than 3.0V or so, because there’s virtually no energy left in the cell at that point. Here’s what HKJ measured on that Efest cell: (I’d suggest recharging any time it gets below ~3.4V, not 2.75V)
The bottom curves are measured at a 5A discharge rate, top curves at 0.2A. The top ones are pretty close to what the battcheck mode sees, so if battcheck says 3.3V that means it’s probably time to recharge.
Can you ask Hank if he make this a limited edition for sale?
I think there will be SS version too
oh…i miss probably any post…where to buy this silver version?
The silver version is not for sale yet.
I heard that the temperature isn’t calibrated on the d4 & the d1 .
I did an experiment to see if there’s much difference in my d4 & d1’s temperature sensing by leaving them overnight at room temperature in the same place & the results were d4 = 18 *C
& the d1 = 33*C .
I used them for a while then let them cool down for an hour & then did another check & d4=24*C , d1=34*C.
So they each read a difference of 10-15*C,
Both had freshly charged batteries.
Yes, the temperature sensor is not factory-calibrated… so measurements differ from unit to unit. That’s part of why it has a calibration function for the user to set its temperature limit.
Today I found out if I go camping I’ll be good with this D4, paper and a black marker lol.
And no, I did not colored that container black lol.
My D1 & D4 reads .1volts lower than my fluke meter.
With a full battery @4.2 both units read 4.1 volts.
Dang Nev, you got bad ones, send em on over to me and I’ll spank em for ya, put em on the shelf of shame… 
There is, unfortunately, some variation in the reference voltage used in the attiny85. IIRC, it can vary anywhere from 1.0V to 1.2V and still be in spec, and the battcheck calculations are done by comparing VCC to Vref with an assumption that Vref is 1.1V.
This isn’t about the emitter choice, it’s random variation in the MCU. Not much can be done about it, aside from manually calibrating each unit with custom firmware or custom settings.
I might try to add a way to calibrate these things without reflashing in future drivers, like the FW3A, but I wouldn’t count on anything soon. There isn’t always ROM space to devote to user-calibration options, or a spare pin to use for things like optical programming. However, I would still like to make something which can be calibrated by selecting options on a web page then holding the light up to the page while it blinks binary data to a built-in optical sensor.
I hope my D1s ( on its way) will be a bad one too 
… blinks binary data to an optical sensor
… merely hold it up to an open window on the screen
are we going high tech here at BLF or WHAT?
Our very own ToyKeeper can stay at home and become famous for flashlight code. You heard it first here people, Budget Light Forum bursting the proverbial seams of the box…