This is my second project since I began my public project deadline framework, and my first instructable. The first project wasn't extremely technical, so I don't really feel that it is necessary to make an instructable for it.
Project: I wanted to start out with something simple that could just be a fun conversation piece, and came up with the idea with a user controlled RGB LED lantern. To make it a bit more interesting and coffee table worthy, I housed the electronics in an antique lantern body that I picked up at an Antique store. It turned out pretty well, and got the appropriate "oohs" and "aahs" when handed around for people to play with. There is a photo of the finished product below, as well as a lantern showing the ways a user can affect the lantern's operation.
There are two "Modes" that the lantern operates in. The first mode is simply color cycling. The user can change the speed the colors change and the brightness. The second mode is a solid color, and the user can change the color and the brightness.
Step 1: Materials
For this project, the parts I used were:
Antique Miner's Lantern (~$20)
Arduino Pro ($19.95)
2x RGB LED's (2 x $1.95 = $3.90)
Battery Holder - 4xAA Square ($1.95)
JST Jumper Wire ($0.95)
2x Rotary Encoders (2 x $1.08 = $2.16)
1/8" plastic sheet ($3.45)
3 resistors: from my toolbox. I don't remember what values I used, but will look them up and update this later.
6 capacitors: I used 1microF, but 10picoF is what I was aiming for. I only had larger values on hand, and my deadline was fast approaching, so I used a slightly less than optimal solution.
6 screws: 4 for attaching the Arduino, 2 for the plastic. I tapped the holes in the wood, but if you had some short wood screws, that could work, too.
4 standoffs: These are small standoffs to screw the Arduino into.
Epoxy or some other glue for plastic to metal and metal to metal.
Step 2: Prepare Lantern Base
I mounted the electronics inside what used to be the oil reservoir of the lantern, which was designed to have a small cap as the only access. In order to use the space, then, I had to cut off the bottom of the lantern, exposing the interior.
Before cutting on the lantern, I made sure to take the glass out to protect it. (Picture 2) In order to remove the glass, you lift up on the "lid" of the lantern, and then tilt it to one side. It only tilts to one side, and it barely clears when the lid is lifted all the way up. Once you have it tilted, it should be relatively easy to pull the glass out of the base.
Once the glass is out, remove the "wick holder", shown in the pictures, by twisting it counter clockwise and lifting out. Disassemble the two pieces, and discard the "wick extender" because it just gets in the way.
The next step is probably the only step in the process that I feel has safety concerns associated with it. Please be very careful. You are cutting into metal, which will shoot sparks and debris out. Don't cut yourself, be careful of eyes and skin, and make sure there is nothing combustible near you as you do this. I am not responsible for any injury, loss of property, or any other thing that you get into because you didn't take the proper precautions.
Anyway, once you have the lantern upside down in a stable location, use a dremel tool with a cutting wheel to cut out inside the bottom lip all the way around. You want to leave the original lip as a base so that it sits level and still looks in its original condition when you are done. The beauty of this project comes from the antique look with the modern electronics, so the goal is to make it look like a normal miner's lantern until you look under the bottom or turn it on.
Another note: while I was cutting away the bottom of the lantern, smoke started billowing through the hole. I was a bit concerned, for one main reason: I was shooting sparks into an old kerosene reservoir, and that seemed like it may have a few possible pitfalls, no matter how dry the reservoir is and the fact that kerosene is not very explosive... However, it turned out that the burning was because there was an old wick from the lantern that had fallen into the reservoir, and as I was shooting sparks into it, it started smoldering slowly.
Another thing to watch out for is that the metal can get very hot as you are cutting it. It will take a bit of work to cut, as it's a stronger metal (I believe it's iron), and will require some time and effort to cut and then smooth out a bit.
Sorry I didn't take many good pictures of this step. I wasn't especially organized early on in this project. You can see the base after it has been removed in the pictures, though.
Once the bottom has been cut out, you can reattach the wick holder. I also tried to brush up the lantern a bit, because it was pretty dirty, but I liked the look of the rust, so I didn't clean it too thoroughly so it could keep a good amount of its charm.
Step 3: Frost Glass
This step is pretty easy but very important. If you just put the LEDs in the lantern with clear glass, they are just a point of light in the middle of it. Etching the glass hides the LEDs so they are not apparent until the lantern is turned on, and they also provide a nice glow while the LEDs do their thing.
For etching glass, you just buy some etching cream and apply to the interior of the glass with a paint brush. Let it sit for a little bit, then wash off. I wanted a very uneven look, so I didn't worry about making it smooth.
Some notes on this step: I found that the etch did not take especially well, and I had to etch it three times in order to get the opacity I wanted. I am not sure if this is because of the way I rinsed it or because the glass was especially resistant to the etch or what. This was my first time ever etching anything, so I'm not sure how it compares.
Step 4: Assemble Circuit
I need to put together a schematic, but I'm still working on it. Sorry.
Step 5: Program Arduino
I have yet to comment out this code, so it's not as useful as it could be, but I will do that and repost it as soon as I get it done.
Step 6: Assemble
Finally things are coming into place. Things you need to do to assemble it:
Cut the plastic into a semicircle and drill holes for screws and encoders.
Cut the scrap wood into two standoffs.
Glue the wood into the base.
Glue the battery holder into the base.
Glue the metal standoffs into the base (for mounting the Arduino).
Feed the LEDs through the hole.
Screw the Arduino in place.
Attach the encoders to the plastic.
Screw the plastic in place.
None of these steps are that difficult, but I would recommend caution when gluing in the battery holder. If you clamp it too tight while gluing, it can be very difficult to get batteries in and out. Also, for gluing the metal standoffs for the Arduno in place, I made a jig out of another piece of plastic, and clamped that in place while it glued. I was leery of clamping on the Arduino and also that if the glue somehow stuck it in place, I wouldn't be able to remove it if I needed to.
Step 7: Finished Product
There you have it. It works! Please let me know if you have any further ideas for the lantern.
I have two encoders with push buttons, but am only using one of the push buttons. I'm not sure what the other one should be used for.
I have some ideas that for holidays, I could put special programming on the board so it would cycle holiday colors or something. I'm not sure how to implement this yet, but if you have any ideas, I would be happy to hear them.
Thank you very much for reading my instructable.