*BLF LT1 Lantern Project) (updated Nov,17,2020)

To go further off-topic, how about the ATTiny 1616 ?
I did some comparisons while looking around for my own driver.

Also, having a 2nd quasi-standard MCU for more demanding drivers next to the ATTiny85 would be something nice to have.

Biggest drawback possibly is that it is only supported in the newest 8.1 gcc release, many needed code-changes and that you need a different programmer.

Primary advantages:

  • Many more PWM pins (for example, Timer0 has 4 compare registers in 16-bit mode and 8 in 8-bit mode)
  • DAC support
  • Single-Wire programming (UPDI Port)
  • Small 3x3x0.9 20-pin VQFN package


Also re: MCU pins, don’t forget that we can use a dirt cheap shift register to control the 7135s that are not being PWM’d. So 3 MCU pins for discrete steps, and PWM on 1 7135 for each color channel. It would require integration into the firmware, although coding for such a thing isn’t the most burdensome, but I’ll let TK speak for any difficulties that might be specific to the FSM firmware.

logic example in pseudo code:

totalRamp = 255
numChips = 8
stepsPerChip = totalRamp / numChips

chipsToShiftOn = currentLevel / stepsPerChip
remainder = currentLevel % stepsPerChip
pwmLevel = mapRemainderToByte(remainder)

shiftRegOutput(color, chipsToShiftOn)
pwmOutput(color, pwmLevel)

I agree with using what we have currently developed to get this light into production, and can imagine a V2 ~6-9 months behind would be a reasonable thing for those not able/willing to mod the V1.

For a V2, a buck driver really does make sense to me in this specific application. How it stacks up in real world efficiency is another question though. The 7135s are going to be shedding a lot of voltage the entire runtime. Only positive thing there is that it’ll be fully regulated, but that’s a lot of wasted energy that I’d love to try and eliminate.

This 1S buck driver development (again, not for a V1 lantern) would pay huge dividends to the rest of the community, who are once again forced back to 7135 drivers with the majority of ‘non-hotrod’ builds using the latest emitters. 2A would be okay, 3A good, and 4A great. I’ve been out of the loop for a while on the driver development side of things, so maybe something close to this already exists?

Cheers! And thanks to all for their past and continued efforts :beer:

Have you toured a PCB manufacturing plant and spoken to the production engineers about what makes their job most difficult ?

Usually daft designs, but they struggle on and make them anyway.

I have, many times, but mostly working on very exotic boards with upwards of 16 layers, blind and buried vias, polyimide dielectrics, Invar constraining layers, Z-axis expansion requiring innovative through-hole plating techniques (actually no through-holes), etc. Designed to last indefinitely, exoatmospheric. So I am a bit fussy.

Here are a couple of vids. showing how a basic 4 layer board is constructed:

Take a look at the German way: https://www.youtube.com/watch?v=T7S40GYESbY

Then contrast with the Chinese way, quite possibly where your PCBs come from (they make multi-project panels).: https://www.youtube.com/watch?v=ljOoGyCso8s

Cringe worthy Mansplaining on this one.

But in both cases, note that the drilling operation is the key mechanical process, each hole drilled individually, with a physical drill. Everything else is just lamination, photo plot exposure, developing, etching, plating, QC etc. which costs the same for any design. It is drilling the holes that costs money (drill wear and machine time, let them get blunt and no amount of plasma de-smear will fix it before applying black-hole/shadow process to get the electroplating started.)

On the Chinese video, drilling is at 13”22’

On the German one, 3”30’

In both cases, rather glossed over. Because it is a key technology for commercial competitiveness, if you can work out how to do it better/faster/cheaper that gives you an edge.

If you get into commercial production quantities, you will learn this.

Just imagine the capital equipment costs of setting up a modern PCB Fab, the staffing and training costs (they have to be really good, not easy to find, most youngsters don’t have the discipline), then there are the environmental controls, all those chemicals, heavy metals, etc.

You can’t just pour e.g. copper sulphate down the drain anymore. it would also be a waste, if you might need it to plate-up things then you can, but you will need a chem-lab to control the process (you need one anyway, one skilled educated person can do that, but OMG it would be a boring job.)

Bye the way, these rapid prototyping services are stupidly cheap. They are giving away the boards for barely the price of postage and packaging, it’s really altruism, hoping to encourage young engineers, and/or get the production contract. If they had been available when I was learning I might have taken a different direction.

If you will PM me an e-mail address, I’ll send you some jpegs showing my observations. It may just be that your software has rendered the design files incorrectly, happens all the time in PCB layout.

At the risk of being boring, here is the video that I should have posted first. Newbury Electronics, some of the nicest people, who really know their stuff, I’ve used them a lot, as I suspect have many UK people.

You’ll learn more from this one I think.

Eventually, yes. But not until the toolchain is more commonplace. For example, debian/stable uses gcc-avr 4.9.2 and debian/unstable is only updated to 5.4.0. So I’m sticking to architectures which are supported in those.

I’ve noticed people drawing a distinction between the words “lamp” and “lantern”, but I’m not clear on what the difference actually is. Can someone define it for me, please?

That spec looks perfect for my purposes :slight_smile:

Personally, I’d rather see two ports. That way, the plug / unplug mechanical wear will be spread out. Charging input via Micro USB or USB-C, powerbank output via full-size USB-A or USB-C.

I’m also not convinced by the idea of USB Power Delivery, because I don’t know how a Power Delivery port works with old-style USB devices. How would the single Power Delivery port figure out whether to take a charge from an old USB wall wart or send power to an old USB-chargeable phone?

I agree with this. The way to maximise the reliability of electronic components is to stop well short of their maximum ratings.

Do you draw these images yourself, ToyKeeper? You always seem to have one to hand for every occasion! They’re really nicely done, I smile whenever I see a new one :slight_smile:

Of course not, silly.

I just strike a pose and levitate the camera for a quick selfie.

Just to comment more on the USB C train, another benefit is the increased durability of the USB C port of the previous standard of micro USB. USB C as a spec is built like a tank, as compared to micro USB where I have personally experienced a number of cables and even a few ports going out over time. Granted I personally have not had a USB C phone for as long as I had been using micro USB, but I do feel that usb C would help the long term durability of the flashlight. This of course is in conjunction with the other benefits of USB C, being that it will likely be the ubiquitous port for the next 10 years, is reversable, can exchange power easily both ways, and saves space compared to USB A. Plus a single USB C port is easier to protect against water than a micro USB/USB A combo. I really hope this light comes with USB C. I’ll still buy one if it doesn’t, but it’s just one of the main reasons I got excited for this lights development anyways.

If Barry can source the USB-C interface plug/port without increasing cost per lantern to much we will go with USB-C. (as its the future format for much everything atm.

Ohh man! I’m SO cautiously excited about this!

In this context, a lantern is a portable lamp.

I.e. it has a handle for carrying it about (well this one doesn’t yet, but it better had if I’m going to buy one, otherwise it isn’t actually a lantern.) And it has a self contained power source.

E.g. I have an Anglepoise lamp on my desk. Plugged into the mains. This is not a lantern.

I also have a Vapalux M1 lantern (actually four) which I can carry around at base-camp, for beach and boat fishing. It also kicks out 1 kW of heat and runs for ten hours from 1 litre of paraffin, whilst shining as brightly as a 100W incandescent bulb. All done with a mantle, not an LED. It is the first thing that I would reach for in a SHTF situation, together with a jerrycan of paraffin. Particularly if the weather was chilly or very damp, and I needed to e.g. dry out clothes, on an airer above it.


Thank you :+1:

I am also interested in one perhaps also with sometimes named extras.

I take one for sure and depending on price maybe another 2-3

Realisticly WHEN could we expect this lantern??? Soon? this year? beginning of next year? in time for the next ice age?

I suspect like me some of us are needing/wanting a lantern like this sooner rather than later…

I know I for one and one other member of the forum who I know well are now relooking at the CL30R again which means we would very likely not bother with this one… I know some of you will say just hold out but when we use lanterns almost daily in autumn/winter for work and play I have to start and look at the need not the want. And currently I NEED to start an look to replace my current CL25R’s with something. But I WANT the BLF Lantern so the NEED out ways the want(was going to say Trumps the want but Trump is now a Dirty word)

SO a simple answer would be nice…thank you

It is done when it is done :wink:

So a TRUMP response!!!