Inspector Gadget: Making Penny’s Computer Book

2023-10-17 | By bekathwia

License: See Original Project

Today, I’m sharing a special Arduino project – a replica of Penny’s computer book from ‎Inspector Gadget.‎

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I carved out a real book to fill it with electronics that look and behave like the book in the cartoon. ‎It’s powered by an Arduino Nano ESP32, which is available at DigiKey.‎

Research

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The first step to any good prop replica is thorough research. I gathered up a bunch of visuals of ‎Penny’s book to inform my bill of materials. It’s a relatively thick book with a blue cover, and it’s ‎got a small screen and button matrix on the cover, though you never actually see Penny using ‎this feature in the show.‎

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On the inside left, there’s a 3x4 button panel, a portrait-oriented screen, twelve illuminated green ‎buttons, a white button that lights up red, and three small square buttons, one each red, yellow, ‎and blue. On the inside right, there’s a large screen, which I plan to emulate stylistically rather ‎than literally.‎

Supplies

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To shop for the parts I needed, I used DigiKey’s extensive catalog filters. Here's a list of all the ‎parts:

Arduino Nano ESP32 1050-ABX00092-ND
Arduino MEGA2560 1050-1018-ND
USB cable (C-type and B-type)
Solderful breadboard DKS-SOLDERBREAD#02-ND
‎2.4” TFT display 1528-1471-ND
Gray buttons x12 EG2576-ND
Green illuminated buttons x12 563-2302-ND
White button illuminated red UB215SKG035C-1JB-ND
Square buttons in red EG1305-ND, blue EG2550-ND, and yellow EG2549-ND
Audio FX board 1528-1491-ND
Speaker 1528-4445-ND
LCD display 1528-1502-ND with I2C backpack 1528-1446-ND
‎4x4 matrix keypad 1528-2672-ND
NeoPixel stick 1528-1594-ND
Perfboard
USB battery pack or lipoly battery and 5V boost converter
‎30g stranded wire
Thick book
Blue paint mixed with matte medium
Black paper
Bookstand

Tools:‎

Making the Body of the Book

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For the main body of the book, I looked into blank books but couldn’t find any thick enough to ‎look right or hold all the components. So, I figured the least terrible printed hard-cover book to ‎destroy would be a collection of stories that are not at all scarce.‎

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I cut the cover to make way for a character LCD and matrix button panel. I sandwiched my ‎small cutting mat in the book to prevent cutting further than the cover layer.‎

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Inside, I laid out the parts for the left panel and arranged the button sets onto some small ‎perfboards. The mockup was looking good, so I could go ahead and solder the buttons in place.‎

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Once I had the holes in the cover made and verified the components fit, I got to painting the ‎book blue. I used a mixture of blue acrylic paint and acrylic matte medium, and I covered the ‎interior pages of the book with painter’s tape so I could easily handle the whole thing, painted the ‎front, back, and spine, and set it up to dry overnight.‎

Then I tested out my button panel by wiring it up to an Arduino Uno running a simple program to ‎toggle the LED on and off when the button is pressed.‎

Making the Inside of the Book

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The next step is where things start to get messy– cutting out the interior body of the book. I used ‎a ruler and utility knife to make progressively deeper cuts through the pages and used some ‎clamps to help hold the pages in place. I also cut a passageway through the bound edge, so I ‎could run wires between the two sides of the open book.‎

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I wired up the rest of the green button panel and fed its stranded wires through the hole I had cut ‎through the spine. Each button is wired up like the big white one shown here– all grounds are ‎connected to one wire, and then another two wires go to the switch and the LED.‎

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Next, it was time to install the other tested components into the book. I soldered stranded wires to ‎a TFT display and threaded them to the right side of the book.‎

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I connected the gray button panel to an audio FX board loaded with sounds from the show and ‎installed the speaker in the right side of the book. Then, I used little pieces of cardboard and my ‎hot glue gun to secure the components in place.‎

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I gave up on the idea that the book would fold shut again, so I glued the pages to each other in ‎the flipped-open position. I used rulers and clamps to hold the pages together while the glue dried.‎

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I’m using the Arduino Nano ESP32 as the microcontroller brain of this project. It’s got wifi and ‎Bluetooth crammed into a tiny footprint, supports both Arduino and MicroPython, and it’s ‎compatible with the Arduino IoT Cloud. I like that it has castellated pins so I can solder it directly ‎to a breadboard and keep my circuit profile as low as possible.‎

The Uncut Pages

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Before I could embed any more components into the right side, I needed to sort out the ‎remaining uncut pages. Using a separate paper template cut to match the interface, I cut a few ‎pages to serve as the compartment’s solid cover.‎

Then I cut a piece of black paper to match the openings on the left, and one big opening on the ‎right. Since some of the printed pages and component perfboard was visible, I used smaller ‎pieces of black paper to shore up the layer behind the black paper.‎

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I used that rectangle to guide cuts through the remaining right-side pages to create one large ‎cavity where the microcontroller can live.‎

The Electronics

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I have the ESP32 board driving the display and fun Wi-Fi features of this project, but it simply ‎doesn’t have enough i/o pins to deal with all the buttons and LEDs wired up on the left side, so I ‎employed an Arduino MEGA dedicated just to the illuminated buttons. They share power and ‎ground.‎

The MEGA also drives the pixel animation on a NeoPixel stick, which I’m using to simulate a ‎screen animation from the book in the show. I took a tip from Nerdforge and layered printed ‎transparency and paper to create a graphic with more dimension.‎

More About the WiFi

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The program generates a network you can join called Penny’s Computer Book, which launches ‎a captive portal after you join it.‎

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The page you’re shown has buttons that control some different outputs on the TFT display ‎including the MAD graphic, calling Brain the dog, and showing you the components used to build ‎the book.‎

Project Code and Circuit Diagram

Here is the code for both the Arduino Nano ESP32 and MEGA.‎

And the circuit diagram for this project:‎

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This project will be on display at the DigiKey booth at Maker Faire Rome 2023, along with ‎Penny’s video watch, which I’ll show you how to build in a future post.