The Skull CTF

by Wokwi

A mind-bending hardware puzzle in three acts

View all updates Apr 16, 2021

From Out the Muck

by Uri Shaked

Ahoy Mateys!

Hopelessly Stuck

Shouldst thou find thyself hopelessly stuck, as did one miserable soul who wrote to us, we emplore thee to armor thy spirit against dispair and consider performing the rituals revealed below:

  1. Flagellate thyself with the ATtiny45 datasheet. (It's long and not very easy to understand. We are aware. But it does contain everything you need to know about the ATtiny45 chip...)
  2. Redeem thy soul by watching the AVR: Architecture, Assembly & Reverse Engineering online course. You'll learn how to nagivate that enormous datasheet, explore the inner-workings of AVR chips, and fiddle with the simulator.

And when you truly hit bottom—when that final moment of existential dread comes for what remains of your dignity—we invite you to draw power from the following incantation: SatH’oTS IaGWtL. ¹

Early Furcula

"I think the difficulty change between the first two levels is just right for me, and I like how the challenges are building on top of the previous steps instead of being unconnected puzzles."

…said the first person to Capture the Flag. Will you be next?

ChallengeFirst to solveSolved to date
Capture the FlagH|_|3H|_|31
Mind Control
The Virus
Medulla Oblongata

¹ Suffering at the Hands (?) of The Skull Is a Great Way to Learn

About the Author

Uri Shaked


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Product Choices


The Skull

A single The Skull CTF board (☠)


SparkFun Programmer

From the Crowd Supply Basics project.

Design your own puzzles and load them into The Skull's brain using this programmer! Mini USB cable not included.

AVR Pocket Programmer by SparkFun


EconoStik Header: DR VT SMT 2x3

From the Crowd Supply Basics project.

Use with the SparkFun Programmer.

One Amphenol FCI EconoStik™ 2.54mm Header. SMD/SMT Mounting style, Straight angled male pins, gold-plating. Voltage rating: 110 V



Wokwi creates tools for the Arduino and maker community, such as AVR8js, the Open source Arduino Simulator, and GoodArduinoCode.

Uri Shaked

JA Electronics


PCB Fabrication & PCB Assembly

See Also

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