Project Lamplighter - my homemade LED keychain fob

[archimedes]

Yes, it looks fantastic !

 

[KuanR]

That looks great! I'm interested to know more about the latest setup

 

[mcbrat]

nice. a copper one of those with that warm glow would be awesome!

 

[calipsoii]

Thanks for all the interest guys! It's super busy in my household and my updates might be a little slow so bear with me.

The LED is a 2x1mm SMD suspended on tiny wires inside 8mm glass tubing. I temporarily abandoned the Pyrex tubing since it was too hard to cut and switched to laboratory "soft glass". I've done all I can to harden the glass and it's caged on all sides by metal so we'll see how durable it is. I've dropped my keys a couple times with no problem but testing will continue.

The circuit draws 35μA from 4x LR41 cells. It could be much more efficient, longer running and cheaper if I switched to LR44's but I don't like their larger diameter. The fob is exactly as wide as I want it to be right now so I'm willing to buy $4 worth of cells every 6 months.

The LED's glass chamber is capped on both ends by white plastic which helps reflect the light and does a great job lighting the entire window. At night on my bedside table it glows like a tiny campfire and I really enjoy the look.

There are a few things on my To-Do list for the next one:

• Increase internal battery chamber diameter slightly
• Aquarium caulking on both ends of the window to help seal against water/dust
• Reinforce wires so they don't buckle under the stress of assembly
• Destructive testing (read: throwing this thing at my driveway over and over) to see how sturdy the glass window is

I'm really excited about having a working prototype and it makes me very proud to see it hanging from the ignition when I'm driving home in the dark. I hope to have a 2nd one built soon for testing and then I hope to make a few for anyone on here who would be interested.

Stay tuned!

 

[DrafterDan]

I like the 'caged' look, very unique.

 

[mcmc]

That is so awesome and what a marvel of engineering!
I also agree with you on thinner being worth the couple bucks a year =)

I know it would require some additional engineering but maybe you could offer different sizes for different batteries?

Also - have you thought about burying the SMD in Norland61? That would take care of sturdiness issues!

 

[gunga]

That is sooo cool. Just a mini keychain oil lantern...

 

[bmetcalfe28]

I WANT ONE or MORE. Great work man keep after it I agree with above post on the Copper also.

 

[sassaquin]

That is wicked cool. :thumbsup:
And yes, I am interested in purchasing one.

 

[KuanR]

I'm definitely interested and this will be worn around my neck! Please put me down for one

 

[Icarus]

Can you post a close-up of the LED please? :thanks:

I like that it is made from brass! :twothumbs

 

[Mr. Nobody]

I want one !

 

[calipsoii]

nice. a copper one of those with that warm glow would be awesome!

C101 copper almost tore my old lathe apart. I haven't tried it on the new one but that experience scared me enough to have a healthy respect for it. May give a shot in the future but not right now. I have been working in bronze though! Little redder than brass and looks better than copper when tarnished.

Also - have you thought about burying the SMD in Norland61?

Filling the glass tube with Norland would probably cost a couple hundred dollars! It does a great job securing things in tiny spaces but it's not economical to use in large quantities. As for potting just the emitter in epoxy, it's not really needed as the solder holds it plenty tight. The wires are my problem - keeping them taut is a challenge.

Can you post a close-up of the LED please?

Please disregard the curly wire - one of them snapped loose during final installation and I have no way to fix it on this prototype.

 

[bmetcalfe28]

Man these are really awesome. Hope you will be releasing before too long.

 

[Icarus]

As for potting just the emitter in epoxy, it's not really needed as the solder holds it plenty tight. The wires are my problem - keeping them taut is a challenge.



Please disregard the curly wire - one of them snapped loose during final installation and I have no way to fix it on this prototype.

Thank you very much for posting those pictures! They are very good! :thumbsup:

As for the wires to the LED, I see that both wires are going to the top of the tube. It might be easier to keep the wires straight and holding the LED in place when you add a thin brass disk at the top and bottom of the glass tube and run/solder the wires from the LED through a hole in the center of the brass disk.

 

[calipsoii]

solder the wires from the LED through a hole in the center of the brass disk.

No can do my friend, the wires are carrying the current to the LED. Soldering them to a disk would cause an electrical short which is why I'm using white Delrin. A think a bit of tape or some caulking would do the trick though!

 

[Icarus]

Supposing the brass housing is connected to the - of the batteries, the bottom brass disk could be connected to the - of the LED and make contact with the bottom of the lantern. The top brass disk connected to the + of the LED could have a brass nippel to make contact with the + of the battery. I don't know how the lantern looks inside but if necessary a delrin disk + brass nippel could be used as the top disk of the glass tube. Then there is no risk for an electrical short.

 

[nfetterly]

Add me to your list. I subscribed to the thread a few days ago. Love bronze, have 2 watches made from bronze.

 

[Nitroz]

Encapsulating that in clear resin or epoxy would be nice, and would add protection to the wires and the LED.

Put me on the list for a brass.

 

[Illum]

Encapsulating that in clear resin or epoxy would be nice, and would add protection to the wires and the LED.

Put me on the list for a brass.

one possible problem with that is that as resin cures it produces quite a bit of heat. Whats the word of that wreaking havoc on an SMT LED?