Make you dog light up during your night-time walks! Still on an LED high (and still have a lot of LED stuff left over from my first project), I decided that it would be helpful to make some sort of light doohickey that I can attach to my dog's collar when I walk him at night. His black fur has a nice sheen, but it sure makes it difficult to see where he is and *what* he's chewing on at night (ewww) at the not-so-well-lit dog park near my house.
The end result is a nifty mod resin clip that shines a semi-diffused LED light operated on 2 AA batteries through a switch. I used a silicone mold and clear resin to make the body (it was my first time casting!). Of course, a lot of these steps can be modified to personal preference. But the most important thing is: make sure that the simple circuit is safe and secured, and that the resin body + battery case is not too heavy! You might need to adjust what battery source and circuit you will need based on the size of your pet. Cisco (pictured below) is 90+ pounds.
MATERIALS FOR MAKING THE BODY:
(1) set of mold making rubber kit
(1) set of clear resin casting kit
(1) sandpaper at 150
(4+) mixing cups
(3+) wooden stir sticks
(1) can of mold release spray
(1) container for the mold
(1) object you want the mold of, in this case, a doggy bag bone-shaped dispenser
*optional (1) pack of air-dry molding clay if you want to make your own bone
MATERIALS FOR THE LED BATTERY PACK:
(1) 2 AA batteries
(1) battery case for 2 AA batteries (the one I got actually had the switch built in)
(1) 3.6 volt white LED (has no dimming or problems lighting up with the 3 volts from the batteries)
(2) velcro dots
a bit of electrical tape
a bit of chromatic/reflective tape
(1) dorky name tag clip
(1) strong cement glue or super clue
-air dusting can spray
Step 1: Prepping the Battery Case
The battery case I got actually had the switch build on the one of the larger sides. Naturally, that side is the side that will be facing outside of the resin body.
I trimmed the LED leads to about 1/4" long and spread them away from each other a bit. I also trimmed the battery case wires so that they're the right length to have the LED light sit in the center. I twisted the positive red wire to the positive smaller-headed LED lead and the black negative wire to the larger-headed LED lead. I'm not soldering until I test it for a while. The white 3.6 volt LED light works does light up and has no dimming problems with the 2x1.5 volts of battery juice going through it for 15 minutes. Then I soldered the LED leads to their counterpart wires after seeing that everything was wired correctly.
I covered the wires and the soldering areas with electric tape as insulation. Then I taped down the wire to the case so that the LED sits right smack in the center. I painted the sides of the battery pack white and I covered the LED side with some reflective duct tape. (In hopes that the light will diffuse and reflect a lot more when it's fitted inside the Glow Bone resin body...but I don't think I know enough about light refraction and reflection to be honest.)
Step 2: Making the Mold
When choosing the object to make a mold out of, make sure that the battery case can fit within the shape, and that it has a flat backside (this is why I am only casting half of my object since it doesn't have a flat side). The bone shape I chose seem to house the battery case nicely, with a margin of 1/8" from all four sides of the battery case. Use some modeling clay to make a little handle or ring onto your object.
I placed some coins in the bone object for stability since it was hollow and would float. Use shoddy water displacement to guesstimate how much mold rubber solution you will need. Aim to make a bit more than that amount.
Spritz the mold release spray in the plastic container and all over the bone object and wait for however long your spray's instructions tell you to wait.
Wear your safety goggles and gloves and start preparing the mold solutions according to the kit's instructions, and get'cho mold on!
After curing time, plop out your object and voila! You got your mold for the resin body!
PS. You might need to make a hairline incision along the inner arch of the little handle in order to get the clay handle out.
Step 3: Casting the Resin Body
The battery pack will not be totally embedded in the resin body-- the body and the battery case must be separate entities so that switching batteries will be possible. Cover your prepped battery case (without the batteries) and LED light with a layer of foil, a layer of plastic wrap, and another layer of foil. Make sure to smooth out the side with the LED-- that side will be faced down in the resin later. Cover the whole thing with scotch tape. To cover any possible rips.
To prevent overflowing of the resin, use the water displacement method again and figure out how much resin is needed to be put in the mold now with the added volume of the battery case. Aim to make a little more than that amount.
Spray some of the mold release all over the rubber mold (don't forget to aim inside the handle) and all over the now-foil-armored battery pack.
Strap up your safety goggles and rubber gloves and start preparing the clear resin cast solution according to your kit's instructions. Pour the solution into the mold.
Wait for an hour or two, or until the solution is in a soft ball stage of viscosity. Take the covered battery pack, aim it so that your margins are consistent, and place the battery case into the resin. Since the resin is very viscous after an hour or two, the battery case will not sink to the bottom, thus piercing through the resin body. However, the battery case might float unevenly so use a coin to even it out.
Wait for the resin to cure completely (about three days). Plop the resin out of the silicone mold, and pull the battery case out from the resin. Yay! Resin body complete!...almost.
Sand the outer surface (the "show surface") and the battery imprint side of the resin body to achieve a nice, even frosty texture. The sanding will diffuse the LED light more evenly from its central position. Use computer air dusting spray to get the sanded resin dust off.
Step 4: Finishing Touches
How is the battery case going to fit into the resin body? Good ol' velcro of course! Take your velcro dots and cement glue the fuzzier side ones to the battery pack, one on each side of the LED. Glue the more abrasive-sided dots to the inside surface of the resin body at appropriate spots. After the glue dries completely, fit the battery case into the resin body. We're almost there!
Instead of just any clamp-style clip, I opted to use an old nerdy convention nametag holder (okay, okay, fine, it was from Blizzcon 2005). With this kind of nametag clip, I can clip the Glow Bone onto the collar AND I can also use the snap tag and have it hang from the collar.
Glue down the clip onto the battery case. I thread the snap tag through the little handle so it wouldn't lean or tilt forward.
Switch it on and let your hound shine in the night!
Step 5: TEH AFTERMATH!
Here are some notes from using the Glow Bone for the past 4 days:
-Cisco seems oblivious to it when I put it on but he thinks it's magic when I switch the light on.
-I can see where he is clearly when I'm 10 meters away from him at night in the dog park.
-Other dogs like sniffing it.
-When CIsco sprints, the Glow Bone does bounce off his chest. In fear that one day he's going to run so fast that the Glow Bone bounces off his chest so much that it hits his lower jaw, I started clipping the bone onto his collar rather than hanging it using the snap tag.
-Cisco has no interest in eating the Glow Bone
-He now knows that when it's being clipped onto his collar, it means that he's going to the park, so he gets really excited.
VARIATIONS ON THE PROJECT
Just having the mold and the basic concept mapped out, I'm sure there are plenty of rad ways to modify this project. Here are some ideas for variations!:
Different Body Shapes
Rectangles, semi-circles, a fish shape...the list goes on. But keep in mind that the weight distribution should be even and that shapes that are more landscape-oriented than portrait-oriented will bounce a lot less when your pet runs due to the distance between the hinge to the collar and the resin body's center of gravity.
Making a Flexible Body
Instead of having a hard resin body, the body can be made out of flexible rubber silicone so it's more like a jacket of an "ipod skin" over the battery case. The downside of this is that most dog toys are made out of silicone, you wouldn't want to make the dog think this is one of his toys that he can destroy in his mouth.
Coloring/Embedding the Body
The resin can always be pigmented to a cool color or have things be embedded in it like a cool kid's retainers. Personalize the Glow Bone can be fun, but I personally just wanted something simple and bright.
Waterproofing and Sloberproofing (from other dogs)
I think the next iteration would have to be "proofing" the Glow Bone. I'll do some research on that!