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Sold/Expired FS: Leash Lantern AA LED lanterns

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Hi CPF!

I'm excited to share with you a project I've been working on for the last little while. I call it the Leash Lantern and it's a task light I built specifically for walking our dog at night. Its purpose is to serve as a bright indication device to make me more visible to drivers.


It gets dark from 4PM to 9AM for almost 6 months up here in Canada, so it can be very difficult as a driver to see pedestrians. My family's had a number of close calls with drivers who haven't seen us in crosswalks. We do use a number of little coin-cell lights from NiteIze, etc but they don't tolerate the subzero temperatures. Within 5 minutes they're dimming and usually 15 mins later they're dead. Plus they're wicked expensive to replace. They're pretty frustrating to use and I doubt they make us that visible, so I got the idea in my head to try and make something better. The lantern runs on 1xAA, so I feed it Energizer L91 Lithium primaries which are good to -40 plus they'll still hold 3500mAh of charge at that temperature.


I machined the first prototype myself a couple years ago, but this little batch was done by a local machinist in my town named Juan. He finds our hobby (in his words) "fascinating" and agreed to help. I'm super happy to have found him - most shops around here work for the oil & gas industry and literally laughed me out of their office when I visited. This batch is machined from solid bronze. The diffuser is white Delrin. It's o-ring sealed and super durable. I've dropped my prototype a great many times into puddles/snow/gravel and it looks pretty rough now but works great.


The driver is my 15VP boost driver. I build them by hand in my basement. The Leash Lantern uses a custom version of the firmware. It's a lot simpler and designed so I can use the Lantern with heavy winter gloves. Just twist on-off. When I come to a crosswalk I quickly turn it off-on and it goes into a timed 30s high-output "crosswalk mode" so cars can see me better, then steps back down to save battery power after I've crossed the street. All the advanced programming menu stuff is still there to play with the brightness and such.


I've received a lot of positive feedback on these! Cars have literally stopped in the street, rolled down the window, and asked "Hey, where'd you get that light?". Other dogwalkers have asked me about it. Cyclists have asked for one for their backpack. So in my opinion they do an excellent job at making me visible outside at night.

If you're interested in more details, or could use a little warm amber light in your life, these are listed for sale on my site. I'm asking $149USD. I build each of these by hand in my basement. They're 100% Made in Canada. And they come with a lifetime warranty against defects so if you have problems just send it back and I'll get it fixed up for you.

I'd love if you'd swing by and take a look. :)
https://copperandcurrent.com/products/leash-lantern

Thanks for looking and feel free to post with any questions or comments!

Best regards,

- Mike
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Thanks Arch! Never left, just don't have the time these days for my comprehensive build logs. Spend my free hour each night tinkering and building.

This batch is a very pleasing amber color, like a warm campfire following you around. They're super useful and I like them alot!

Great to see you back, and with (warm tinted) cool new stuff !

Cheers buddy :)
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Thanks thermal guy! Life got quite busy now that we have a couple children so I don't post as much anymore, but I still manage to spend some time with my lights every now and then. :)

Just now seeing your work. Great stuff!
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Awesome, I'm in.

Sent from my SM-N910T using Tapatalk

Love your stuff. I'm definitely in for one [emoji106]

Sent from my Pixel 3 using Tapatalk

Thanks so much for the positive words! Honest truth is that we use the lantern nightly (and have for several years) and I don't leave the house without it when it's dark outside. I've been tweaking on them for a while now to get the firmware and feel just so. I'm hopeful others might have use for one and find the same thing.

I have a dozen lovingly boxed up and ready to go, so should you want to try one they're available for order on my site.

Warmest regards :)

- Mike
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Very nice!
Does this driver accept 1.2v? What is the low voltage cut-off?

Yes, the driver has a voltage range of 0.9-Vled. It's intended for ~1.5V but would probably operate just fine on 3V.

There isn't a hard voltage cut-off in the firmware, but at 0.9V the circuit will begin to flash a low voltage warning (2 blinks). It will then continue to run until the battery dies.

It also monitors current through the LED every 8s and if it cannot stay in regulation (brightness is set too high for remaining battery voltage) the circuit will begin to step down through the brightness levels to extend runtime and prevent battery overload.
 

K2-bk-bl-rd

Flashlight Enthusiast
Joined
Jan 17, 2008
Messages
1,679
Would a warm tint, high CRI LED be a option? It's a really cool idea, but a different led, would make it more tempting for my uses!
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
Would a warm tint, high CRI LED be a option? It's a really cool idea, but a different led, would make it more tempting for my uses!

Certainly! If someone was pretty committed to buying one with a different LED, I'd be happy to make that happen. :)


 

mcbrat

Flashlight Enthusiast
Joined
Jan 28, 2013
Messages
3,971
Location
Iowa
The lantern will give 2 quick blinks every 30s when your
battery is getting low (< 0.9V).

at what point will it stop doing this? (is there a minimum V required for the flash or will it work like a vampire circuit?
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
at what point will it stop doing this? (is there a minimum V required for the flash or will it work like a vampire circuit?

It's not a linear circuit, it's a switching boost regulator, so when the circuit drops out of regulation it does so very quickly (maybe over the span of 10-30 mins?). It stays in regulation for almost the entire usable battery life, so by the time it's drained all the juice out the cell and dropped out of regulation, the battery is pretty much done after that.

I added two firmware features to help manage things:
  • Low battery monitoring, which polls the battery voltage every 30 seconds and gives a double-blink when it drops below 0.9V (there is some hysteresis built into this measurement to prevent false positives). This is just an indicator to the user, and no actions are taken within the circuit.
  • Output stepdown, which polls the output current every 8 seconds, and if it's not in regulation, blinks once and steps down 2 output levels (out of 24). It'll continue to do this until it reaches an output where it can stay regulated. In testing this greatly extends the battery life, as the cell's no longer being driven hard trying to provide the requested output at the cost of ever increasing battery current.

Both features can be turned off in the programming menu if you'd prefer just to let the circuit attempt to keep things in regulation without any kind of smart management. In that situation, once the circuit cannot maintain regulation the output will just naturally taper off, heat will build up, and it'll struggle to provide as much juice as it's able.
 

calipsoii

Flashlight Enthusiast
Joined
Apr 21, 2010
Messages
1,412
These are super clever. I just need to get a dog.

Oh thanks eala! Don't need a dog, just need some darkness. :) I clipped one to my belt loop when we went out on Halloween so the cars could see us. Worked a treat!
 
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