Make an LED Cat Harness




Introduction: Make an LED Cat Harness

About: I'm an Industrial Designer by background, and I've worked on children's toys, backpacks, luggage, and footwear. Outside of work, I'm super interested in the intersection of textiles and technology and how so...

If you've got an adventure cat, you'll want to sew him this LED vest so that you can go on nighttime adventures. Camping with cats?! Yes!

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Step 1: Gather Materials



C Conductive Thread:

D Breathable Mesh Fabric (Anything you have that is breathable should be good, but this is what I had leftover from another project) : (About a 1 foot x 2 foot piece)

E Swatch of scrap material that matches your mesh (about 3"x3")

F Regular Sewing Needles

G Heavy Duty Machine Sewing Needles

H Knit Machine Sewing Needles

I Fabric Scissors :

J Extra Wide, Double Fold Bias Tape (X2)

K 1" Side Release Buckle:

L 1" Webbing (About 6")

M 1" D Rings (X2)

N Silver Sharpie

O Measuring Tape

P Sticky Velcro:

Q Seam Ripper

R Straight Pins

S Regular Sewing Machine Thread

T Bobbin

U Cat

Not Pictured: Paper ,Sewing Machine

Step 2: Make Your Pattern

Print out the pattern provided and cut it out. The colors are for reference when piecing the pattern together, but it's not strictly necessary to print in color - you can just refer to the computer. I made mine using kraft paper (similar to a paper grocery bag), but you can use regular printer paper if that's all you have handy. Cut out the pattern pieces.

Tape the pattern pieces together along the short, straight edges. Match the colored lines together as shown in the diagram in image 5.

You can use a paperclip to mimic where velcro will later fasten the pattern together.

Step 3: Try It on Your Cat

This can be tricky, depending on how chill your cat is. My cat is pretty cool (and he's used to my shenanigans), but it still takes some skill. I recommend laying the pattern down on the floor and then dropping your cat's paws into the arm holes from above as shown in image 1. Then it's a scramble to wrap the vest around his torso before he fidgets out of it.

What you are looking for here is overall fit. I developed this pattern for my cat (who is large, part MainCoon about 13lbs) so you may need to make some adjustments to your pattern after seeing how it fits your cat. If you need to alter the pattern, do so now.

Step 4: Cut Out the Fabric Pieces

Put your fabric face down on the table. Lay out your pattern pieces on top in a way that uses the least amount of fabric and trace them with an ink that is visible. I used silver sharpie here to show on black fabric. IMPORTANT: Make sure that all of your pattern pieces are face up.

Your drawn line will be on the outside of the pattern pieces, so you will be drawing a shape that is slightly bigger than the pattern piece itself. Now cut out the pattern pieces, keeping the cut line toward the inside of your drawn line so that you preserve the original size.

Step 5: Prepare a Battery Pocket

To make the battery cover, cut a small piece of scrap fabric. I made mine a 3.5"x3.5" square, but it can be slightly smaller. Fold an edge over and sew a line over the top (top stitch) using a straight stitch on your sewing machine. All you are doing here is eliminating a raw edge on your battery cover.

Next, line up the fabric a couple of inches from the end of PATTERN PIECE 3. You want the fabric piece to overlap enough so that you can fit the entire Lilypad underneath with room to spare around the edge for sewing.

Pin the square in place (image 4). Next, open up a piece of the double fold bias tape and pin it so that a folded edge aligns with the long edge of pattern piece 3 and continue the tape over the fabric square (image 5).

Step 6: Sew in the First Piece of Bias Tape

You need to use special needles to sew knit fabric (image 1). Use the key that came with your machine for turning the screw to loosen the existing needle, or use a coin if you can't find the key. Change the needle and re-tighten the screw.

Next, sew straight down the middle of the bias tape as close to the middle folded edge as possible. Your result should look like this (image 4).

Step 7: Begin Your Circuit

Thread you needle with conductive thread. Be patient, the thread can fray.

Study the circuit diagram provided in image 2 to visualize where your components will go. Image 3 shows the fabric pieces along with the circuit. As you can see, the Lilypad is sewn underneath the fabric cover you have already created, and the rest of the circuit is sewn into the bias tape that you just attached in the previous step.

Sew your Lilypad into place by repeatedly looping the thread through the POSITIVE hole on the board. Sew tight, close stitches to assure a solid connection. Then sew the thread away from the battery and into the binding to get to the spot where you will put your first LED.

Step 8: Attach the Positive Side of the LEDs

Sew in the LEDs through their positive holes, making sure that each LED is in the same orientation as in the diagram and that you keep the thread to the same side of the LEDs. Do not switch sides of the LEDs or there will be no room for your negative thread.

The spacing isn't too important here, just see how many LEDs you have and how they fit nicely into the pattern piece. This is the only place you need LEDs, so feel free to use all you've got!

Step 9: Sew in the Negative Thread

I got anxious to see that my circuit was working, so I stopped sewing the positive thread and began to sew the negative thread simultaneously. If you like, you can sew in the positive side of all of the LEDs before starting this step.

WITH A NEW THREAD, sew through the negative hole on the Lilypad repeatedly to form a solid connection. Continue to follow the diagram for the track of the negative thread, making sure you never cross the positive thread. As soon as you have the battery attached to one LED, you can turn on your circuit to see the first LED light up*

*If it isn't lighting up, try flipping the battery. If it still isn't working, try a new battery (they drain quickly!). If you still aren't having any luck, make double sure that the threads aren't crossing anywhere.

Step 10: Your Piece Should Look Like This

When you are finished sewing in all of the LEDs, turn on the battery pack and make sure everything is lit. Twist it around a little and make sure nothing is flickering. If you see a flicker, you are probably experiencing a short circuit, which would mean that somewhere in your circuit the negative and positive threads are touching.

Next, fold the bias tape over the LEDs.

Step 11: Close the Bias Tape

This step is tricky, but you want to flip over your pattern piece and start to tack down the bias tape. Your LEDs should be completely covered. As you can see in my photos, I made my way down the tape by sewing at an angle. I used the angle so that my seam would not be visible from the front of the piece, but this was purely aesthetic. At the end of this step, you should have the bias tape completely sewn down and the ends of it trimmed to be the same size as the pattern piece.

Step 12: Begin to Bind the Rest of the Edges

The point of binding is to eliminate raw edges of your fabric both for comfort and aesthetic reasons.

Unless you are a wonderful seamstress, or you have access to a production quality binding machine, your binding will likely not look perfect. As you can see in my finished product, there are many bumps in my prototype. Ideally you would be able to use stretch binding, but I could not find any for this project.

Here I opened up the bias tape and sewed down the middle line.

Step 13: Keep Binding the Edges

Using the same principle as in the previous steps, bind the rest of the edges on all 3 pattern pieces.

I found that in leu of stretch binding, it was helpful to make small slits with my scissors into one side of the binding for curved surfaces (image 1). Put the slit side down and turn the binding in small increments as you make your way around a curve (Image 2). Afterward, pin down the other side of the binding (image 4) and sew down the remaining edge (image 5).
As you can see in these images, I interchangeably use the machine's zipper foot (image 2) with the standard foot. I like that the zipper foot is clear and that I can have it closer to the actual seam, so I sometimes use it in tricky spots. There are pros and cons, so it's up to you which one you like best.

Step 14: Close the Battery Pocket

If you are able to execute tight turns with your binding, you can bind this edge the same as your previous ones. Since I don't have that ability, I cut a small piece of fabric and folded in the edges (image 1) and attached it to the open end of the pocket. I then attached two pieces of sticky-backed velcro.

Step 15: Attach the Pattern Pieces Together

Again, using the diagram provided in Step 3, line up the pattern pieces. Sew them together by pushing the edges right up to each other and using the zig zag stitch on your machine (image 1). This is better than overlapping the two fabric pieces because you want to avoid a big lump of the thick fabric. Once all of the seams are closed with zig stitches, cover the stitches with bias tape. Cut a short piece of bias tape and fold it over the seam in a loop (image 2 and 3) and sew over the top using a regular stitch or a zig stitch (image 4).

Next, attach a piece of sticky velcro soft side ( the inverse of your previous velcro ) in a strip on pattern piece 2.

Step 16: Attach the Buckles

For this step, you'll need to switch to heavy duty needles (image 1)Take a 4" piece of webbing and thread a D ring through it. Fold it in the middle and then attach the buckles (image 2). At this point, you should try the vest on your cat to determine where to place the buckles. The buckles should be 1-2 inches above the velcro straps, where the shoulder blades would be (but cats don't have a collar bone!) Place the webbing where you like it and then tack it down using the zig zag stitch on your machine.

Step 17: Tack Down the Velcro

The sticky velcro won't be sufficient for actually holding your cat in place. Don't skip this step our else your cat can squirm his way out of the vest! Danger!

However you can squeeze your machine around the vest, tack down both pieces of velcro in all 4 corners. You can see where I fit in some stitches in the above pictures.

Step 18: Try It On!

Isn't my kitty handsome? ;)

I used the leash that came with his old harness. Most leashes have a trigger hook on the end so they will attach easily to the D rings.

Step 19: Explore!

That's all! Take your cat outside at night for some fresh air. Camp. Walk. Whatever he likes.

If you liked my Instructable, please vote for it in the Cat Competition.

There's a ton of great reading on actually camping your cat, which you should absolutely read for the safety of your cat if that's an activity you'd like to try.

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    4 Discussions


    3 years ago

    Beautiful detail and organization to your presentation and construction...very impressive. Unfortunately, in my neighborhood, Peter (The Coyote) would love the visual dinner bell...a Cautionary California Tale.


    3 years ago

    Do you need a code to make this work? How do you get the lights to turn on?


    Reply 3 years ago

    No code needed! The Lilypad battery pack that I linked to has an on/off switch, so all you do is turn the Lilypad on, and the circuit will light up the LEDs!