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  • Author Author: tariq.ahmad
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Unhackable Arduino Switch Matrix -- Episode 456

The other day at the hackerspace Dave was talking with members how to improve the safety in the space. Especially how to prevent other people from leaving dangerous devices running unattended. They quickly came up with a button that needs to be pressed once in a while, or otherwise the machines power would be shut off. Since it's a hackerspace the expectation of people building crude "Arduino with servo" devices to circumvent such a device was high. But having a 4x4 button matrix that would indicated a random button to press sounded tougher to get around, so the idea for this project was born. It also looks suspiciously like a midi-controller.

Bill of Materials

Product Name Manufacturer Quantity Buy Kit
ABX00028 - NANO EVERY DEVELOPMENT BRD, 8BIT AVR ARDUINO 1 Buy Now
1403010049 - 3D Printer Filament, 1.75mm Dia, White, PLA FILAMENTIVE 1 Buy Now
1403010042 - 3D Printer Filament, 1.75mm Dia, Black, PLA FILAMENTIVE 1 Buy Now
1403010037 - 3D Printer Filament, 1.75mm Dia, Orange, PLA FILAMENTIVE 1 Buy Now
Rotary Potentiometer, Conductive Plastic, 100 kohm, 1 Turns, Antilog, 200 mW, ± 20%, P160 Series TT ELECTRONICS / BI TECHNOLOGIES 4 Buy Now
Tactile Switch, B3F Series, Top Actuated, Through Hole, Round Button, 100 gf, 50mA at 24VDC OMRON 64 Buy Now

 

Additional Parts:

 

Product Name

relay board

Neopixel LED strip 30LEDs / cm

4 relay knobs
Attachments:
Additional Resources.zip
image
Unhackable Arduino Switch Matrix

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  • If someone really wanted to do that wouldn't a light sensor be all that you need to detect which button to press? They just make 16 of the device that you're trying to pretect against, and put a light sensor on each one. Or one button-pusher and sensor on a movable rail.

     

    Seems extremely un-unhackable to me. There are much better uses for a set of 16 backlit buttons.

  • in reply to vrighter

    Hi! Not sure what device you're describing here. Do you mean I should protect against a matrix of button pushing servos that trigger when the light of the button is turned on? Intriguing. what would be your solution, if would have the lights on on all of them and just change the color of the button? Right now the code isn't even testing if all buttons are pressed simultaneously image

     

    The title "unhackable" was a bit more clickbaity, but putting "dead man" switch on the title sounded like something the youtube algorithm wouldn't like.

     

    Thank you for registering so we could talk about this image

  • in reply to davedarko

    Not referring to specific device. Just the thing you mentioned you're trying to protect against, specifically any device designed to press one button repeatedly. In this case that button pushing device just needs a fatter finger that hits all buttons at the same time (but that's easy to fix in code, obviously) since pressing all of them would work anyway.

     

    If you changed color, I would just look at the brightest button.

     

    If they all changed colors then the button to press would have to be some specific color. Can't have the legitimate user not being able to figure out which button to press. But at least they'd all be lit up at the same time, defeating the brightness trick above. Of course you could just use an rgb color sensor. Things start getting more complicated for an average person.

     

    But keep in mind you made this for a hacker space. As in, a space which hosts the type of people who would build this type of thing just for fun (and maybe because you called it unhackable, clickbaity title or not, I would still take that as a challenge image )

  • in reply to vrighter

    one of the hackers that I respect highly just said: "I would just rip out the cable and short it otherwise, to get around it image

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