Digital Pumpkin Carving



P5.JS (JavaScript)



Two Weeks


Lydia Jessup

S. J. Zhang


When we were tasked to doing something fun for Halloween, we didn’t want to do another ghost with a servo motor inside. After a few meetings, our idea settled as a pumpkin drawing competition, and maybe Hey! we can later use all the data to teach a machine how to draw pumpkins.

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We found the ideal 32 x 32 LED matrix for our purpose, but without a data sheet. However we managed to find a few other people on the internet that worked on similar projects and followed their processes and recommendations on the power and set up.


I coded a simple drawing pad in JavaScript with P5.JS library to match the 32 x 32 LED matrix. A boolean expression checks if the mouse is pressed within the square range of any circle’s center. When the state is true, an opacity change is activated and the circle’s coordinate is printed. We later mapped the pixel coordinates into LED’s unit coordinate and send the string into the serial communication with the Arduino board.


After we got the matrix to map what we have on screen, we started making a simple pumpkin shell for the matrix. We wanted a nice rounded corner on the exterior so we tapped the corner LEDs to prevent lights shinning through.


The last thing before setting it up at the Halloween party was giving it a nice interface. My partner Lydia was very keen on capturing my css moment.

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Now go back to the top and try it one more time.