*BLF LT1 Lantern Project* (batch #2 rolling in soon!)

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DBSAR
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Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

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Phlogiston
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DBSAR wrote:
Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

I got a bit confused about the final decision: did you go for the 7135 version or the FET version?

DBSAR
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Phlogiston wrote:
DBSAR wrote:
Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

I got a bit confused about the final decision: did you go for the 7135 version or the FET version?

i believe the FET version was decided on & the design for that model sent from Lexel to me.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

Phlogiston
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Thank you Smile

ToyKeeper
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Should I take a shot at making code for this driver even though I don’t have the hardware to test on? At least then Barry & Co would have something to flash on the MCU.

I can’t guarantee it would work, but … it might.

I can probably get the tint-control stuff working, at least, since that seems to use pretty standard PWM. But I’m not sure about powerbank functions. I need more info about what the USB and opamp enable pin is supposed to do. Lexel, how should that work? Does the pin enable both the USB powerbank circuit and the primary LED output? I’m not sure if the pin needs to go high for regular LED modes, or for powering other devices, or for charging the lantern itself, or a combination.

DBSAR
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ToyKeeper wrote:
Should I take a shot at making code for this driver even though I don’t have the hardware to test on? At least then Barry & Co would have something to flash on the MCU.

I can’t guarantee it would work, but … it might.

I can probably get the tint-control stuff working, at least, since that seems to use pretty standard PWM. But I’m not sure about powerbank functions. I need more info about what the USB and opamp enable pin is supposed to do. Lexel, how should that work? Does the pin enable both the USB powerbank circuit and the primary LED output? I’m not sure if the pin needs to go high for regular LED modes, or for powering other devices, or for charging the lantern itself, or a combination.

I believe Lexel offered to build a test driver, (at an unknown cost, which i am unable to dedicate any large amount of funds to at this time) but i believe Barry was going to have their engineers look at the driver design specs Lexel sent me to see if they can build that FET driver posted earlier. Then it may be possible for them to build some test units to send you. (building the driver is out of my ability range) but you can contact Barry or Lexel directly if you want to get more info on the driver hardware.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

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Jabe1
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Put me down for one, maybe two.

k125bw
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@listbot add 2

im interested in 2 lanterns

pechelman
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sbslider][quote=Ilmatic wrote:

You can check the “live” version of the list anytime in the links below.

interest list sorted by entry number

interest list sorted by user names

It appears the “live” version isn’t being updated?

Last entry I see in the google doc is 979 CrashOne from post 2587

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I took a short break from updating the interest list as I have been on vacation, and now work travel. Also I was hoping the listbot would pick the job up but it appears to not be working. I will comb the thread over the next few days and get caught up. I apologize for any inconvenience or burden this has caused folks.

PocketSammich wrote: I don’t need this, but I want it. Please sign me up.

pechelman
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No worries at all on my end. Just thought it would be worth mentioning. Probably easier to catch up now than in a couple of months Smile

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pechelman wrote:
No worries at all on my end. Just thought it would be worth mentioning. Probably easier to catch up now than in a couple of months Smile

Definitely. I went through that once already.

PocketSammich wrote: I don’t need this, but I want it. Please sign me up.

DBSAR
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sbslider wrote:
pechelman wrote:
No worries at all on my end. Just thought it would be worth mentioning. Probably easier to catch up now than in a couple of months Smile
Definitely. I went through that once already.

I still have to post the one you sent me last week, ( i been a bit overloaded with work this past week or two.)

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

Tom Tom
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DBSAR wrote:
Phlogiston wrote:
DBSAR wrote:
Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

I got a bit confused about the final decision: did you go for the 7135 version or the FET version?

i believe the FET version was decided on & the design for that model sent from Lexel to me.

That disappoints me, I think this is the last thing that needs a FET instead of well managed linear drive. Either one, or two, or even three banks of 7135s. Even just one bank with PWM. Not many 7135s needed to achieve desired lumens.

Which would be more consistent throughout the cell discharge, assuming suitable LED Vf, as well as much more efficient (run-time).

ISTR that the prototype uses the Q8 driver with the FET disconnected and a NanjG 7135 driver connected to the gate pin instead, as a second 7135 bank.

Also not sure how it fits in with the two different sets of colour temp LEDs and mixing. I don’t see how a FET has any purpose in that arrangement, just two banks of e.g. 7135s, one for the lower colour temp LEDs, the other for the higher.

Perhaps a FET could just override any of that subtlety and give “Max Power” for those who insist (maybe they shouldn’t be buying a practical lantern).

The only point of a FET is to (over) drive the LEDs to the absolute max. that the particular combination of cell max. current and ESR, state of charge, LED transfer characteristic etc. can deliver. In short blasts. Inefficiently. Sure, wind it down with fast PWM but that will make no difference to the inefficiency (short run time and inconsistent output as the cells discharge).

To summarise: why does this lantern need a FET driver ?

But I am not on the interest list, just an observer, so crack on please.

I hope I have mis-understood.

DBSAR
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Tom Tom wrote:
DBSAR wrote:
Phlogiston wrote:
DBSAR wrote:
Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

I got a bit confused about the final decision: did you go for the 7135 version or the FET version?

i believe the FET version was decided on & the design for that model sent from Lexel to me.

That disappoints me, I think this is the last thing that needs a FET instead of well managed linear drive. Either one, or two, or even three banks of 7135s. Even just one bank with PWM. Not many 7135s needed to achieve desired lumens.

Which would be more consistent throughout the cell discharge, assuming suitable LED Vf, as well as much more efficient (run-time).

ISTR that the prototype uses the Q8 driver with the FET disconnected and a NanjG 7135 driver connected to the gate pin instead, as a second 7135 bank.

Also not sure how it fits in with the two different sets of colour temp LEDs and mixing. I don’t see how a FET has any purpose in that arrangement, just two banks of e.g. 7135s, one for the lower colour temp LEDs, the other for the higher.

Perhaps a FET could just override any of that subtlety and give “Max Power” for those who insist (maybe they shouldn’t be buying a practical lantern).

The only point of a FET is to (over) drive the LEDs to the absolute max. that the particular combination of cell max. current and ESR, state of charge, LED transfer characteristic etc. can deliver. In short blasts. Inefficiently. Sure, wind it down with fast PWM but that will make no difference to the inefficiency (short run time and inconsistent output as the cells discharge).

To summarise: why does this lantern need a FET driver ?

But I am not on the interest list, just an observer, so crack on please.

I hope I have mis-understood.

I had originally planned on the 7135s, but left the driver & firmware for that part in the lands of Lexel & Toykeeper as they know much more than i do about driver design & circuits. Maybe chat with them about your thoughts on it.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

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Tom Tom wrote:
DBSAR wrote:
Phlogiston wrote:
DBSAR wrote:
Hi everyone, I was away for a couple days, but back now. I sent the driver files & info to Barry from Lexel.

I got a bit confused about the final decision: did you go for the 7135 version or the FET version?

i believe the FET version was decided on & the design for that model sent from Lexel to me.

That disappoints me, I think this is the last thing that needs a FET instead of well managed linear drive. Either one, or two, or even three banks of 7135s. Even just one bank with PWM. Not many 7135s needed to achieve desired lumens.

Which would be more consistent throughout the cell discharge, assuming suitable LED Vf, as well as much more efficient (run-time).

ISTR that the prototype uses the Q8 driver with the FET disconnected and a NanjG 7135 driver connected to the gate pin instead, as a second 7135 bank.

Also not sure how it fits in with the two different sets of colour temp LEDs and mixing. I don’t see how a FET has any purpose in that arrangement, just two banks of e.g. 7135s, one for the lower colour temp LEDs, the other for the higher.

Perhaps a FET could just override any of that subtlety and give “Max Power” for those who insist (maybe they shouldn’t be buying a practical lantern).

The only point of a FET is to (over) drive the LEDs to the absolute max. that the particular combination of cell max. current and ESR, state of charge, LED transfer characteristic etc. can deliver. In short blasts. Inefficiently. Sure, wind it down with fast PWM but that will make no difference to the inefficiency (short run time and inconsistent output as the cells discharge).

To summarise: why does this lantern need a FET driver ?

But I am not on the interest list, just an observer, so crack on please.

I hope I have mis-understood.


You have misunderstood.
The point is to have linear driver. But instead of a bank of 7135s it should be based on a FET driven in linear mode.
This won’t be a hot rod driven as far as batteries allow but a nicely regulated light.
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Agro wrote:
You have misunderstood. The point is to have linear driver. But instead of a bank of 7135s it should be based on a FET driven in linear mode. This won’t be a hot rod driven as far as batteries allow but a nicely regulated light.

Good to hear that. that’s the way to go.

I didn’t realise that Lexel had developed a linear variable driver (using a FET, but that’s not the important bit).

AFAIK only Led4Power has a proven one at the moment.

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Co-owner/Engineer at STO Flashlights.

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I am a real fan of minimizing power losses (e.g., most lumins for the longest time). I don’t care what color the light is. I am one of those that view this as an emergency lamp. If I understand what is being debated, FET + PWM yields the best use of battery resources vs a whole bunch of analog devices. And reduces extraneous heat generation.

I remain a: No holes in the light, no charging of external devices, no charging of internal batteries. It is a light. It has batteries. Stop there. That is a lamp.

puglife2
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Having AM radio could be a nice addition tho

spinynorman
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I think a bunch of lanterns like this would come in pretty handy around here the next few days (weeks). – From the NC coast.

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To build one prototype driver
about 17$ Oshpark with slow shipping for 3 boards
Order parts I do not have stocked 20$ With shipping costs
5$ parts I have stocked
6-7$ assembly time
5$ testing time
DHL express to china 35$

But if they make it in China its cheaper and faster to make one

When the light goes in production we can talk about free samples or a payment for the design, at the moment funds for me building a prototype would not speed it up

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@Lexel: What are the specs of the power bank circuit in the final design?

For instance:

  • Max. output current to USB devices
  • Charge rate of the lantern batteries
  • USB output type: e.g Type-A with BC1.2 DCP / Type-C with PD 2.0/3.0
  • USB input type: e.g microUSB 5V / Type-C with PD 2.0/3.0
  • Possibility of using the lantern while being charged
  • Possibility of using the lantern while charging external devices

Thanks for the clarification and keep up the good work Smile

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Table 4. Charging Parameter Default Setting
DEFAULT MODE bq25895
Charging Voltage 4.208 V
Charging Current 2.048 A
Pre-charge Current 128 mA
Termination Current 256 mA
Temperature Profile Cold/Hot
Safety Timer 12 hour

USB type is mechanical of the light not driver
max. USB out of the chip is 2.4A but this gets reduced by a resistor on DELs layout as I understood to 1.5A
Batteries get charged with 2A as we do not use the chips internal bus

the chip supports up to 5A, but likely the Powerbank chip needs to be programmed differently not sure how that works

Lantern can be used while charging/discharging,
there is an enable pin from MCU not sure how this will be configured if output is enabled or not when the lantern is off

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Pleaae put me down for one (this is the reason I just joined BLF 5 minutes ago).

After reading much of this thread, I have been looking for this lantern for the longest time!

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spinynorman wrote:
I think a bunch of lanterns like this would come in pretty handy around here the next few days (weeks). – From the NC coast.

Yeah, I’m sure they would. But any light capable of lighting up a room well enough to see will be handy, TBH. This storm likely won’t care if you have DBSAR lanterns or Q8’s with a Styrofoam cup on top as a makeshift diffuser. Wink

EDIT: Oh yeah, if you’re at the coast, you should really evacuate if you can. Sadly, some people can’t or won’t. I’m pretty far inland at Salisbury, but it’s probably going to get interesting here too, if Florence goes as predicted.

The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy

DBSAR
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Lexel wrote:
To build one prototype driver
about 17$ Oshpark with slow shipping for 3 boards
Order parts I do not have stocked 20$ With shipping costs
5$ parts I have stocked
6-7$ assembly time
5$ testing time
DHL express to china 35$

But if they make it in China its cheaper and faster to make one

When the light goes in production we can talk about free samples or a payment for the design, at the moment funds for me building a prototype would not speed it up

definitely understandable. ( especially with the higher cost of shipping to the China engineers.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

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alternety wrote:
I am a real fan of minimizing power losses (e.g., most lumins for the longest time). I don’t care what color the light is. I am one of those that view this as an emergency lamp. If I understand what is being debated, FET + PWM yields the best use of battery resources vs a whole bunch of analog devices. And reduces extraneous heat generation.

I remain a: No holes in the light, no charging of external devices, no charging of internal batteries. It is a light. It has batteries. Stop there. That is a lamp.

No, you have that the wrong way around. FET+PWM (or in DC FET= “Turbo”) is the least efficient way of driving an LED. But can give spectacular output when over-driving LEDs. Irrelevant for a lantern, actually undesirable.

Look at all the chatter about which FET, cell, LED, host, reflector, MCPCB, copper addition, spring mods. etc. can, in combination, give “Max Power”—-) for a few seconds before they overheat. Really not relevant for a lantern IMHO.

FET+1, the staple BLF driver architecture, uses 7135 linear up to 350 mA, then the FET kicks in (inefficiently) above that. The single 7135 also allows the efficient firefly and moonlight modes that would not be possible with just a crude FET. And would have some utility in a lantern.

Linear drive, typically using a bunch of 7135s, either banked up in sophisticated manner like Mike C does, or double-down or triple-down, or just one bank sized for max. output, with fast PWM to dim down, is a decent compromise of efficiency, cost, complexity, ease of design.

Personally I wish the 7135 had never been invented. It has stifled innovation for so many years because it works and scales so well, and is inexpensive. Due to being cloned (sometimes well, sometimes not) by so many others (I don’t even think AMC exists any more).

What Led4Power is doing is much more clever, but proprietary. And I fully agree it should be proprietary, speaking as a professional electronics engineer who has to make a living.

This has always been the case for BLF hardware, there is a great reluctance to actually publish schematic diagrams and bills of material for review and critique, I have mostly had to reverse-engineer them from e.g. the OSHpark layouts.

I see that this is also the way that some BLF designers are now working, in some sort of collaboration with manufacturers. Be it hardware or firmware. And I support that. OSHpark and the various open source software models are fine, but not something that I particularly embrace. Engineers should be paid for their efforts by commercial manufacturers, no matter how derivative they are.

If they choose to give away their unique innovations, circuit design, algorithms, hard-won empirical knowledge, that’s down to them (I would not). If they simply re-purpose derivative works from others, that’s down to their conscience as to whether they also acknowledge their inspiration.

Decent work should be rewarded. Whether financially, or by seeking popular acclamation, or the worthiness of “charity”, or otherwise.

Motivation is a complicated subject, particularly on social media like this, we are all different, there are no simple truths.

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