6th Annual BLF Handmade Entry (Finished!) - gchart

Ok guys, this is the first time I’ve entered. And I’m going to start small (I have four small kids, so my only “work time” is after everyone is asleep and I can sneak off to the garage). In looking at past entries, even the idea in my head doesn’t hold a candle to the wonderful creations from years past. But alas, you have to start somewhere, right?

Behold, the flip-lantern! Well, at least a sketch of it.

I’m thinking a small cylindrical housing of frosted glass or plastic (whatever item I can find of appropriate size) with flat caps of wood or metal at either end. A cap can be removed to access the “light engine” inside, which will likely be a sandwich of two custom PCBs held together by copper rods, holding a 18650 between them. The plan is for the PCBs to have 4x 80+ CRI 4000K 2835 LEDs on each one (8 total) being powered by a single 7135 for approximately 150 lumens. Also mounted on the PCB will be a mercury tilt switch and a LDO+resistor combo Current Regulating Diode (Semitec S-120T) to drive the LEDs at around 1mA when you flip the lantern upside down. Flip it back upright and the mercury switch will enable the 7135. Pretty basic, but it should be a fun first build.

Stay tuned!


Tasks Completed:

  • Initial sketch done
  • LEDs ordered
  • Components (minus LEDs) received
  • PCBs received
  • Housing completed
  • Prototype built and tested
  • Final PCBs have been populated
  • Battery guard cut, sanded, and polished
  • Solder battery guard in place
  • Solder conducting rods in place
  • Final touch-ups


Tasks In-Progress:

  • Nada


Future Tasks:

  • Nada


Final Pictures

PCBs before assembly

PCB labelling

Internals, front

Internals, back

High power

Low power

Here’s a proper shot of it, before the diffusion foam:

GIF animation



  • Custom PCBs using white solder mask for reflection (Oshpark link)
  • ~150 lumens from 8x 4000K 80-CRI 2835 LEDs (in High mode)
  • On-off switch for traveling/storage
  • Uses a mercury tilt switch to switch between High and Low modes
  • High mode uses a single 7135 to driver 350 mA to the 8 LEDs
  • Low mode uses a 1 mA Current Regulating Diode (Semitec S-120T) to deliver 1 mA to the 8 LEDs
  • End caps are cut from a Poplar plank, shaped via sanding, and then polyurethaned
  • Housing is plastic (cut from a seasoning shaker), roughed up with sandpaper, and sprayed with Frosted Glass spray. Additional diffusion provided by some sheet foam.
  • Battery guard was cut from a 3/4” copper pipe and shaped with a drill, angle grinder, files, sand paper, and then Mother’s Mag Polish
  • Connection between the two PCBs consists of two copper rods. This also provides a bit of structural integrity in addition to the battery guard.

PS - I have 6 extra PCBs from PCBway. I will likely never use them, so if anyone would like to build their own version of this, let me know and I could probably send you a set (sorry… US only, international shipping would be prohibitively expensive).

Cool, looks like a nice idea :+1:

Subscribed :+1:

EDIT: don’t forget:

Thanks for the reminder; done!

Cool idea! :+1:

Subscribed to see how this proceeds. :slight_smile:

Looks cool!

Sounds like you have a plan. :slight_smile:
Maybe you could fit in one of those little usb chargers as well?
Ok, I’m back in my box. :stuck_out_tongue:

subscribed because its a lantern build! :slight_smile:

I like the idea (a TP4056?). I dunno if it’ll fit well into the design, but I’ll definitely keep it in mind if it looks like it’ll fit!

Nice idea, looking forward to watching the progress.

You are the man, to do this that is. :slight_smile:

Do many LEDs in parallel, so they all get a smaller bit of current, that way you get much higher lumens/W and you can get longer runtime :slight_smile:

Ingenious :slight_smile:

Love the tilt idea, though some kind of lockout would be useful. :slight_smile:

Good luck!

Have any of you tried PCBWay or AllPCB for your PCBs? I’m leaning towards PCBWay for this project. I always use Oshpark but I’m looking to get ones with white solder mask. They’re both in China, but seem to have good prices, lots of options, and pretty quick turn around time.

Cant help you there. I’ve only used Oshpark.

Ok, I’m still learning about proper driver designs, so I’m going to throw my schematic and PCB out here for critique before I order it. The PCB has been uploaded to Oshpark, but I will likely be using a different service (see above).


Another note… I decided to simplify a bit and spec out a Current Regulating Diode (1ma version) in place of the LDO+resistor. I’ve never seen one used but they appear pretty basic.

Oh, another thing… While this is one board, I’m basically designing it as if they were two separate ones, the circuitry is independent of each other. One side will be used as the main board of the lantern while the other will be a slave board.

Why is there a ring around the center pad? What purpose does it serve?

Looking at your schematic. Can you describe to me in words how you expect it to function? I’m having a hard time trying to understand it. :person_facepalming:

EDIT: In particular, the switching doesn’t make sense to me. I understand the slide switch disconnects the ground and turns the light off, but what is the tilt switch supposed to accomplish?