I’ve had the pleasure of owning a dog and I really wanted to dress him up for Halloween! We decided he would be a hot dog but I thought it was too simple so I added LEDs to the mustard to light it up a bit. From working at the Tech I’ve learned a lot about soft circuits and sewing with conductive thread so I really wanted to use that on this costume. The issue I ran into was time. With juggling school, work and everything else I was really pressed for time the few nights before Halloween to finish this. At least I got the circuit done even though I didn’t get to add extra decorations to the hotdog. Here’s the steps I took to complete this project.
First I started with the circuit. This was going to take the longest since I was sewing it into the costume. The circuit consisted of 3 parallel sets of 3 LEDs in series for a total of 9 LEDs. Since I was only using a 9V battery I needed resistors on each set of 3 LEDs. I calculated around 410 ohms but ended up using a 390 ohm since that was as close as I could get. I also sewed in a button so I could turn his costume on and off.
Sewn in 390 ohm resistor.
Sewn in 3 prong push button.
I think sewing the circuit took me about an hour. It was tricky trying to keep the thread taught and making sure none of my lines crossed. I bought conductive thread on amazon (just know it’s thicker than normal thread so make sure you have a needle with a bigger eye).
Completed circuit.
Testing the circuit!
Our dog’s name sewn into the side of the hot dog.
I covered the conductive lines with tape so they wouldn’t touch his fur.
I covered the circuit and added a hole for the button.
As I was sewing on each trio, I made sure check the connection as I went along to make sure each set was lighting up. Thank goodness they all lit up so when I went to test all 9 it worked!
It lights up!
Here it is in the dark.
I think this took about a days worth of time to finish this. I’m extremely happy with how it came out. He looked like the cutest little hotdog ever:
My pup being a hot dog.
I had to loop the hot dog costume through his harness so it would stay.
As we were walking around that night he got a lot of compliments from those passing by. I’m definitely going to get started on next year’s costume earlier this time. You can check out the other video I took of him before we left on my Instagram. The only problem I had was keeping his hotdog was slipping off. I had attached it to his harness but it wasn’t really staying. I had to add an extra strip of velcro on one side so I could pull the strap around farther. However, it still slid around a lot so next year I must remember to attach his costume to his actual harness. Here’s a video of the result:
Engineer with a Twist 