Penny Cosplay (Inspector Gadget) Costume

After working on this project over the span of two years, It’s finally time to share my costume for Penny from Inspector Gadget. I made the wig, I made the computer book, I made the watch, I customized the clothes, and I put together a look for the Inspector. In this post, I’ll share how I built each element of this cosplay.


Here are all the supplies I used to make this project:


Penny’s outfit:

Penny’s computer book and Penny’s watch each have their own build instructions.

Inspector’s costume:

Making The Foam Wig

We’ll start from the top and work our way down, starting with the foam wig.

I used a snapback baseball hat as the base for this wig. This way I know it will fit me no matter how I wear my hair, or also will fit somebody else. I cut off the brim and then used plastic wrap and tape to make a pattern. The plastic makes it easy to remove the tape, the tape takes the shape of the outside of the hat, and then I cut it in several places to make it flat.

I traced the resulting pattern onto some thick cosplay foam and marked the front and the back. Then I cut out the pieces using a utility knife and cutting mat and started gluing the pieces together along the cut seams using hot glue.

By the way, if you haven’t treated yourself to the modern convenience of a cordless hot glue gun, or if you know someone still using a corded hot glue gun, this is your sign to get on that for the holidays.

I don’t have a wig form so I improvised with a magic arm and some paper packaging material. As I added the two halves of the foam base to the hat, I decided I wanted a little more space between the back of the wig and the snapback, again for hair management purposes. When I wear a hat I usually clip my hair to the snapback part directly, and this is also a technique to help keep the wig on my head securely.

I added in Penny’s side fringe, which first looked like sideburns, and made me want to make another wig with sideburns. Another time.

Out of the thickest foam in my multipack, I sketched and cut out Penny’s iconic pigtails, and hot glued them to the back of the base.

Then I pulled out my heat gun and started using it to smooth and shape the foam. I had never used this stuff before this project, and it’s super easy and fun. Highly recommend.

I then took thinner foam and cut it into triangular pieces to add more piecing to Penny’s hairdo, as well as pieces to attach to the front side of the pigtails.

After I was happy with the look and shape of the wig, I took it outside to spray paint it bright yellow. I used a rubberized paint so it wouldn’t flake off the flexible foam once it dried.

Making Penny’s Shirt

To make Penny’s shirt, I took a rectangle of white knit jersey fabric and attached it to the torso of a plain red t-shirt. I used a zigzag stitch on my sewing machine to allow the stretchy fabric to continue to stretch.

The pants were made in a similar way– I just added bits of fabric on top of a base pair of green sweatpants. The color choice is super important, though, and the first color light green I bought, online of course, was definitely not looking right, so I had to try again.

Making Penny’s Computer Book

Next up it’s Penny’s Computer Book. I carved out the inside of a book I had painted blue and stuffed it with the most lookalike electronics I could find, referencing my Pinterest board while using the extensive catalog filters on Digi-Key, the sponsor of this video. I actually have a dedicated post about video over on their channel about the computer book project build. It’s got audio from the show, a screen, a bunch of illuminated buttons, a faux display made from LED pixels, and some special Wi-Fi features too using the Arduino Nano ESP32.

Making Penny’s Computer Watch

I’ll be sharing the other microcontroller build for this project, Penny’s computer watch, soon- I’m just putting the finishing touches on this 3D printed project using the Arduino Nicla Voice. You can see this and Penny’s Computer Book in person at the upcoming Maker Faire Rome (2023). I won’t be there this time, sadly, but tell them I sent you and ask for my sticker.

Inspector Gadget’s Costume

Onto Inspector Gadget’s costume. I don’t think folks will necessarily get who Penny is without the inspector, and also my Halloween costume partner is a tall man.

The Inspector’s hat is a plain grey fedora topped with a rotating red light. This is the most approachable DIY out of the whole series because it’s just two Amazon products sewn together. I drilled small holes in the base of the battery-powered light and stitched through them directly to the hat. The Inspector’s got a lot of unwieldy things in his hat, but this look is very wearable and not likely to get you stuck in any doorways.

The rest of the Inspector’s outfit includes the following unaltered clothing items: most importantly: a grey trenchcoat, blue pants, blue tie, white button-down shirt, and a pair of dark solid-color shoes.

Thank you for coming along with me on this multi-media project journey– you know it’s my favorite thing to combine crafts and technology together.

I started this project last year, and then halfway through, my dog Olive got cancer. We tried to treat it but it didn’t work. I prioritized spending time with her and put this project in a box. So I’m glad I finally got it back out of storage and finished it and want to dedicate this project to her. She’s the Brain to my Penny.

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