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View Poll Results: Which board would you like?

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  • 1AA NiMH with strobe

    33 16.10%
  • 1AA NiMH without strobe

    75 36.59%
  • 3.7V Li-Ion with strobe

    63 30.73%
  • 3.7V Li-Ion without strobe

    78 38.05%
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Thread: FS: Microprocessor controlled drivers

  1. #211

    Default Re: Microprocessor controlled drivers

    Love the driver, but I still need a NiMH cell that isn't old and tired...Larryk, where are you?
    Last edited by TranquillityBase; 08-05-2007 at 08:45 PM. Reason: O.T.

  2. #212
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Nice work TB! Is the all shiny pill custom made? The driver fits perfectly.

    I must admit I don't recognize the host. It looks well made and got very nice threads.

  3. #213

    Default Re: Microprocessor controlled drivers

    Quote Originally Posted by RV7 View Post
    Nice work TB! Is the all shiny pill custom made? The driver fits perfectly.

    I must admit I don't recognize the host. It looks well made and got very nice threads.
    Thanks RV7...

    Yes, the heatsink, and the host are custom made...The larger diameter board works perfectly for this design.
    Last edited by TranquillityBase; 08-04-2007 at 02:30 PM.

  4. #214
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers


  5. #215

    Default Re: Microprocessor controlled drivers

    Quote Originally Posted by RV7 View Post
    Maybe I'll try a Cree Q2 next...

  6. #216
    Retired Administrator Norm's Avatar
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    Default Re: Microprocessor controlled drivers

    That's a beautifully little light TB. I'd love to own something as pretty as that.
    Norm

  7. #217
    Flashaholic* larryk's Avatar
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    Talking Re: Microprocessor controlled drivers

    Quote Originally Posted by TranquillityBase View Post
    Sure koala...I chucked the heatsink back in the lathe, held the marker firmly against the tool post, turned the lathe on, and advanced the carridge feed until the marker just touched the part. The lines make centering the LED, much easier...

    Here's a completed 1AA light...RV7 driver, Seoul USVOI (From Photonfanatic) McR20S reflector, and a McClicky switch...Yep, same poop, different day, as far as the light body is concerned, but I had a few solid reasons for choosing this design. One, the head and the switch housing were already completed. Two, I wanted a McR20S light to use for direct comparison with the last light I built. And reason number three, lack of glass and o-rings for a smaller diameter light.

    Love the driver, but I still need a NiMH cell that isn't old and tired...Larryk, where are you?

    I'm right here TB. If you want to try a AA Enloop let me know. I also have some AA E2 Lithium batteries if you want to be the first to push the limits of the driver. OK, forget the E2's and just sell me the light and I'll try them.
    Last edited by larryk; 08-06-2007 at 01:41 AM.
    Collins Dynamics CD-12, CD-12 Magnum, Microfire Warrior, Iluminator HID, Costco HID, ,Maxabeam, Polarian Helios, RayzorLite ,BarnBurner,and a bunch of small lights.

  8. #218

    Default Re: Microprocessor controlled drivers

    Hi RV7,

    I have a couple of questions if you don't mind sharing some of the details of your single AA NiMH design.

    If you would prefer to keep your design's details to yourself that's fine, but I'd love to compare notes because I have also been tinkering around trying to come up with a high output driver that will have reasonable efficiency with only 0.8 to 1.5 volts of drive.

    In PSpice, I can get about 75 percent efficiency with 1.2 volts of input and about 1.4 amps of output current with a reasonably simple all N-Channel MOSFET synchronous rectifier boost converter setup using modern low RDSon devices.

    My circuit uses discreet low cost devices with no fancy 'gate-drivers' etc, and does have a fairly low parts count, but I am wondering if perhaps there may be an even simpler way to do the synchronous rectification now that P-Channel devices have improved to have RDSon specs that are also in the low milliohm range (I created the all N-Channel boost circuit a few years ago when P-Channel RDSon specs were really poor).

    What kind of MOSFETS are you using, and does your boost driver have synchronous rectification or just a Schottky Diode?

    With some MPU's able to source or sink 100ma, I would suppose that good Gate Drive should be possible directly from the Microcontroller itself if bootstrapping is used, but this raises questions of how to insure reliable startup at 0.8 volts or less, since this is below the gate threshold of even today's Super-MOSFET devices.

    What kind of MPU are you using and does it guarantee startup and operation at 0.8v or is it also bootstarapped from the LED voltage (with some kind of startup oscillator to drive the boost converter until the bootstrap voltage kicks in)?

    Just curious how you solved these issues.

  9. #219

    Default Re: Microprocessor controlled drivers

    Larryk and I did some light meter testing last night, and the RV7 1AA light is the only light in my arsenal that gained in brightness as the head warmed up. We tested that particular light with a Energizer 2500 NiMH, Sanyo 2000 NiMH eneloop, Energizer E2 Lithium, and a standard alkaline cell...The eneloop was the clear winner, with the E2 Lithium a close second.

    I don't know why it gains in brightness, but I like it...we probably watched the meter numbers for a good five minutes, and it was still climbing...After the head was fully warmed-up, we quicky switched cells to see the difference between the four test cells.
    Last edited by TranquillityBase; 08-05-2007 at 08:57 PM. Reason: O.T.

  10. #220
    Flashaholic* ledaholic's Avatar
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    Default Re: Microprocessor controlled drivers

    Hey TB,
    What's it gonna take to talk you out of that light?

  11. #221
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    Default Re: Microprocessor controlled drivers

    *
    Last edited by jch79; 08-06-2007 at 01:54 PM.

  12. #222

    Default Re: Microprocessor controlled drivers

    *
    Last edited by TranquillityBase; 08-05-2007 at 08:55 PM. Reason: O.T.

  13. #223
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    Default Re: Microprocessor controlled drivers

    *
    Last edited by jch79; 08-06-2007 at 01:54 PM.

  14. #224
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    Default Re: Microprocessor controlled drivers

    to the gentleman with the gun...



  15. #225
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Quote Originally Posted by Luminescent View Post
    Hi RV7, I have a couple of questions if you don't mind sharing some of the details of your single AA NiMH design...
    I never tried to hide the design by sealing the circuit with goo or sanding off components marks. Anyone with the know how can buy a driver from me, disassemble it and figure out how it works.

    I use N-MOS and Schottky, and a PIC directly driving the gate. Your Spice simulation seems pretty accurate, but I’m yet to see an AA battery that can output 1.4x3/75% amps at 1.2V.
    Last edited by RV7; 08-05-2007 at 08:33 PM.

  16. #226
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Seems everyone is drooling over TB's masterpiece. Maybe TB should start a thread offering it for $1m each?

    Now can we get back on the track of this thread? Thanks.

  17. #227
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    TB, mind sharing your light meter readings?

    Seems E2 isn't that great in high current applications. NiMH still rules!

  18. #228

    Default Re: Microprocessor controlled drivers

    Sorry RV7, I don't own a light meter...I was using Larryk's light meter last night.

    BTW, is there another way to remove the masking agent, without scratching the gold?

  19. #229
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Hi TB, you can try a chemical stripper such as methylene chloride with a swab combined with masking tape. Or you can try scrape with the blade of a butter spreader.

  20. #230

    Default Re: Microprocessor controlled drivers

    Quote Originally Posted by RV7 View Post
    I never tried to hide the design by sealing the circuit with goo or sanding off components marks. Anyone with the know how can buy a driver from me, disassemble it and figure out how it works.

    I use N-MOS and Schottky, and a PIC directly driving the gate. Your Spice simulation seems pretty accurate, but Iím yet to see an AA battery that can output 1.4x3/75% amps at 1.2V.
    Thanks for the info.

    At this high of drive current, I think the LED Vf will be higher (even for a low Vf bin LED) so I would figure:

    1.4 * 3.6 = 5.04 load watts

    5.04 load watts * (1 / 0.75) = 6.72 input watts

    6.72 input watts / 1.0v loaded cell voltage = 6.72 amps at the battery

    I have seen maximum discharge quoted as 2C to 4C for NiMH AA cells and 6.7 amps is only a little above the 3C rate for a 2000mAH cell. I think this would probably be near the cells upper limit, and so even the 1 volt loaded voltage would be a bit overly optimistic, and with constant current regulation at the LED, if the cell voltage drops under load to 0.8 we would exceed the 4C rate.

    NiCad cells have lower overall capacity than NiMH but also have much lower internal resistance, so at this high a discharge current, I am pretty sure that one of the good old politically incorrect NiCad AA's could handle things a lot better, (even though this would be a 6C rate or higher depending on the cells capacity).

    I suspect that the run times would be similar, but the NiMH cell would dump most of it's energy in internal heating, and cell life would be shortened, where the NiCad would have a fairly short discharge time (10 min or less) but would not be damaged.

    So, if you want to try one of your 1AA designs at a really high load current, try a nice fresh high capacity NiCAD cell (be careful though because these cells will put out insanely high currents if something in the circuit fails and short circuits).

    Wonder how long NiCad cells will even continue to be available?

    Does anyone know if there is an absolute cutoff date for sales of NiCad batteries in the U.S. ?

  21. #231
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Yep my black decker cordless vacuum uses NiCad batteries that output 10A! They're getting old and I painfully found they can't be replaced by NiMH batteries.

    I actually tested my driver with some NiCad batteries taken out from old motorola walky talkies. The output is good but runtime is too short and I'm not interested in buying any NiCad.

    For the current design (750mA output), NiMH seems to be the best choice and almost everyone has a bunch of them.

  22. #232
    Flashaholic* AndyTiedye's Avatar
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    Default Re: Microprocessor controlled drivers

    They still use NiCds in solar-powered LED lights.

  23. #233
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    Default Re: Microprocessor controlled drivers

    Will any more AA drivers be available soon?



    Colin.

  24. #234
    Flashaholic* koala's Avatar
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    Default Re: Microprocessor controlled drivers

    Hello RV7,

    Got the drivers today, they are nicely built. I got a chuckle and I probe into the boost circuit. I was expecting some super special boost IC controllers, but it's such a elegant and simple design. I must reinstate that finding the right inductor core and wire turns is hard to achieve. You must be having sore fingers winding those inductors.

    I got numerous boards, so seperated one of the PIC control and the boost. I didn't need the control board in a AA light, so I used the boost. I hadve another light I installed the PIC control. It will be direct driven(plus the miliohms in the mosfet) with 3.6v 17670. I would like to know what's the max current the mosfet can handle, I don't want to blow it up. It seems to be doing fine with 3.4v 660mA.

    Thanks for reading,
    Vince.
    Arc4+ mods/repair. LED drop in for SF E-Series. Onion Rings for SF A2.

  25. #235

    Default Re: Microprocessor controlled drivers

    Hey.. got emm and they look great.
    Nice clean work, just by inspection. Wish I had time to install in something just for actual realtime opinion. I'm sure it will rock with what I read so for..

    ThanX
    X..
    So much to learn, so little time.. ')
    DFW Texas Spring Fling CPF and LPF Flashapalooza, TBA? ')

  26. #236
    Flashaholic RV7's Avatar
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    Default Re: Microprocessor controlled drivers

    Colin, yes more AA drivers in a smaller form factor will be made, but not very soon. This weekend I'm coming to your island and will be busy until the end of the month.

    Vince, the PWM module is perfect for direct drive. It's a piece of cake for the mosfet. Yes you're right that the design is not a revolutionary technology break through. The concept is not new. The key is selecting the right components. The reason it's not found in mass manufactured lights yet is, I guess, because it's not easy to automate the winding and soldering of the inductor (you do get sore fingers winding those inductors).

  27. #237
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    Default Re: Microprocessor controlled drivers

    Quote Originally Posted by RV7 View Post
    Colin, yes more AA drivers in a smaller form factor will be made, but not very soon. This weekend I'm coming to your island and will be busy until the end of the month.
    Great - I'll keep watch for them.

    I hope you enjoy your time in the UK.



    Colin.

  28. #238
    Flashaholic* ledaholic's Avatar
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    Default Re: Microprocessor controlled drivers

    RV7,
    I got my 2 boards yesterday, very nice. I modded my L4 with 1 of your drivers, a SSCP4, and a 18650 body and a 4.5Ah NiMh battery which is the same sixe as a 18650 Li-Ion. This combo should make a really nice light with considerable run time. Thanks for the boards.

  29. #239
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    Default Re: Microprocessor controlled drivers

    Hi RV7 -boards arrived thanks.They are bueaties.

    Did my first mod ever on a DX Cree AA light -worked great. Used a Q5 Cree
    Not as bright as McGizmo XR-19C -but pretty close.
    Very happy with results.

    Cheers
    Dom

  30. #240

    Default Re: Microprocessor controlled drivers

    I received my boards on Monday. Very nice. Many thanks and I hope the subsequent drivers work out just as well.

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