I’m wanting to build my own driver, I’ve got experience making PCBs. I don’t want to reinvent the wheel so I’m trying to find a proven schematic for a very reliable 3 mode flashlight driver. I like the idea of using an ATtiny13a chip (or whatever is equivalent or better) and 7135 regulators, due to simplicity and reliability. I’ve searched on this forum for an hour or so and can’t seem to find anything. Can somebody please point me to a schematic?
Thanks!
There are a couple of old schematics around, but you won’t find them by searching “schematic” because nobody really talks about them. If you search “driver” and find one you like that is uploaded to OSH Park, then you can download at least the source of the PCB, from which you can reverse-engineer a schematic. In some cases, members also upload schematic files and other relevant info about the driver to OSH Park. I have a few drivers up on OSH Park myself, but I never took the time to upload anything except the PCB source for manufacturing. If you’d like, I can give you an old Eagle PCB file of mine. But there are better driver files available, honestly.
As for modes, you will need a firmware, which you can find around here also. Fortunately, they are easier to get, since ToyKeeper has a repository of quite a few of them, HERE <<<
Just grab any NANJG driver. They’re pretty much exactly as you described.
The 105C has “stars” that when solder-shorted to ground tell the µC to do different things.
The 105D doesn’t have those stars, but has the annoying blink-on-low to let you switch modegroups.
Eg: LED Driver Schematic .
What do you think of this driver? OSH Park ~ It should make less heat since it is more efficient than a linear driver.
Does anybody know Alex Wells, and do you think he’d provide an eagle schematic file?
Thanks!
Alex Wells is BLF member “wight” and unfortunately hasn’t been seen here for almost a year. But the driver you picked doesn’t happen to have any source files uploaded. Only Gerber files are in the download link. I forgot a lot of drivers were done that way in the past. Sorry
Have a look at the Texas Avenger series, schematics and shared Oshpark links. Texas Avenger "TA" Driver series - Triple channel + Bistro or Narsil + Clicky or E-switch - The Ultimate open source driver!
Harley Quinn and Del have released things here as well.
Be aware good 7135’s are hard to find. Mountain Electronics and LCSC are the last two places I bought good ones from.
Thanks wtf. I’ve looked at it, and would like to modify the firmware to get 3 specific modes, I need 200ma, 600ma and something like 10hz flashing. I’m using this for taking photos of aquarium fish at night, and these exact intensity levels are perfect for this. The flashing confuses them, making them stay still for a few moments, then switching over to the 200ma or 600ma modes would be for photo graphing whether they are at the front or rear of my aquarium.
I’m guessing I wouldn’t even need the mosfet, and I can find a linear regulator in the SOT89 package rated for 300ma, instead of the hard to find 7135 (rated at 350ma). Then I could just use 2 of these 300ma regulators to get my 600ma, is my thinking correct?
Thanks!
If you can find or make a linear driver that has consistent output levels as the battery discharges it should work fine as long as you pay attention to a few details. If the flashlight host is small and needs to be on for a long time the linear driver could lead to overheating as it burns off excess voltage. Next you need to deal with tint shift, it can change a little or a lot with current changes depending on the led’s used, some people prefer pwm just to avoid tint shift. BLF member Mauuka has posted a lot of led CRI tests here.
Bistro firmware uses a “clicky” switch and can be modified if you don’t mind messing around with C programming. You could make a mode for your photography and then change to a normal flashlight mode using the configuration menu, no reflashing needed. Going from blinky modes to normal modes would be awkward, probably easier just to use a separate light for flashing the fish.
It might be better to just buy a complete driver than buying parts from various places and getting beat up by shipping fees. Mountain electronics sells kits and complete 7135 drivers as well as any other components you might need to modify or build a light for your needs. Led4power and Lexel sell linear drivers but delivery times will be longer due to them being on a different continent. Lexel and Mountain also sell good buck drivers which will run cooler than linear drivers.
I guess I have a unique situation. My LED voltage is 4.1V. My battery cell at full charge is 4.2, but goes to 3.6V as it discharges. What type of driver would work for this? A boost driver?
The most used driver schematic is this which was improved by BLF and lead to 3 channel drivers like TA drivers
the schematic is from TA
R1 19.1k 0603 1% or better
R2 4.7k 0603 1% or better
R3 100k 0603 5% or better
R4 47 Ohm 0603 5% or better
R5 4.7 Ohm 0603 5% or better
7135 350mA Micro One SOT89
C1 10uF 0805 X7R 10V
C2 0.1uF 0603 X7R 10V
OTC 1uF 0603 10% X7R 10V
D1 380mV SOD323 >50mA
Cheap MOSFET that’s rather good
Nexperia PSMN2R4-30MLDX
common good MOSFET´s are
Vishay SIR800 or SIR404
the most current capable with the lowest resistance and gate threshold
Infineon BSC009NE2LS5ATMA
Almost any driver that is made for a single cell lithium battery will work with that voltage range. The photography you plan on doing is what makes it tricky. Most flashlight firmware is designed to keep flashing modes separate from the regular modes to avoid accidentally activating them, so going from flash mode to lighting mode may not be fast enough.
A good picture requires good light so you need to research what leds will look good at both your intended power levels. If the light will be on a short period of time or the light is capable of dissipating the heat developed at your power levels overheating is nothing to worry about. Linear drivers and fully charged batteries are the worst combination for making heat which may or may not be a big deal for you.