Final Project

Oops I Did It Again

A curtain that insists you leave

Oops I Did It Again is a curtain that nudges you to step away when you’ve been in the same space for too long. It’s built around the experience of getting so absorbed in a project that taking a break gets pushed aside and self-care is neglected. When timers or notifications are often simply too easy to ignore. The curtain first is calm and easy to dismiss, but over time it becomes more insistent, shifting from subtle color changes to increasingly intense light patterns until it’s hard to stay put.

It takes the form of a 90s doorway bead curtain, pulling from personal childhood memories of early prized possessions, bought with scarce money, when objects felt important and worth protecting. That familiarity gets turned against you. The curtain can become “distressed” over time, tapping into the tendency to care for others more easily than for yourself. A kind of Tamagotchi—like experience, but one that tricks you into self-care by making you take care of it.

Britney Spears, Robert Sebree 2000

The system detects when someone actually passes through and leaves the room, using motion sensing and a magnetic field sensor to distinguish a person from something smaller like a cat. If no exit is registered, it escalates; if no movement is detected at all, it settles into a resting state. Passing through is rewarded, returning is acknowledged, and over time the system logs this data locally, allowing it to be combined with mood or medication tracking to build insight into longer-term patterns.

System overview

The curtain consists of multiple flexible strands, each containing a series of small light nodes (LEDs). These are controlled by a microcontroller and respond to sensor input.

Input: magnetic field for movement of the curtain, motion sensors to detect entering and exiting
Processing: a microcontroller translates this input into light patterns
Output: LEDs embedded in the strands create a dynamic, semi-transparent display

Design

For the design of my curtain I wanted to challenge myself to stay close to the original, as to evoke those fond childhood memories of having a bead curtain as prized possession I wanted to care for. I also felt the reference may get lost by making a more modern design.

3D design

All the 3D designs for this project are made by me in either Freecad or Blender. For visualization purposes I've sometimes used AI, but never for the actual CAD files send to machines.

Beads

For the beads I've the same design throughout Fab Academy, first appearing in 3D-printing week, later being used in molding and casting week and application programming. For the final beads I've changed it's shaped and size slightly, but kept the overall design the same.

Top bar

Lights

The light patterns get slowly more distressed over time as there is no interaction with the curtain. I've designed this behavior for week 15 with some help from ChatGPT. I then translated them into MicroPython code using Codex, you can find the code in the files section below. In the future I want to custom design my own light patterns.

Electronics

For the electronics I designed two boars, one main PCB housing the microcontroller and exposing all the pins needed for the sensors and lights. The hall sensor has it's own little board and communicates over I2C with the microcontroller. All designs are made in KiCad and processed for the mill using Mods.

Main PCB

Hall sensor PCB

Production

All the parts for this project have been made by me at the Fab Lab at Waag or at home; sometimes with a little help from Henk & Irja and my classmates Chris & Remco, thanks y'll.

Beads

The 200 beads I've printed at home on my Prusa Mini+ using Fiberlogy easy pet-g.

Top bar

The top bar consists of a rail, which is made up of 6 parts holding the electronics and strands in place. These parts have been 3D printed at home using silver PLA by eSun.

Electronics

All electronics have been milled just like documented in week 8. The cables I've made using ribbon cable and a crimp set with Dupont connectors Henk supplied me with. For the mircocontroller I used a Raspberry Pi Pico.

BOM

Main Board

Qty	Component	Notes	Price	Source
1	Raspberry Pi Pico	Main MCU	$6	Waag inventory
2	4.99kΩ resistor	I²C pull-ups for SDA/SCL	$0.20	Waag inventory
2	5-pin header	LED strip outputs (`DATA`)	$1.46	Waag inventory
2	3-pin socket	HC-SR501 connections (`3V3`, `GND`, `DATA`)	$3.22	Waag inventory
1	4-pin socket	TLE493D breakout (`3V3`, `GND`, `SDA`, `SCL`)	$2.13	Waag inventory
1	2-pin header	Power split toward MCU power	$0.47	Waag inventory
1	Custom PCB (main board)	FR1		Waag inventory

Hall Sensor Board

Qty	Component	Notes	Price	Source
1	Infineon TLE493D-A2B6	I²C hall/magnetic sensor	$2	Waag inventory
1	100nF ceramic capacitor	Decoupling cap for TLE493D	$0.07	Waag inventory
1	4-pin header	TLE493D breakout (`3V3`, `GND`, `SDA`, `SCL`)	$0.82	Waag inventory
1	Custom PCB (TLE493D breakout)	FR1		Waag inventory

Misc

Qty	Component	Notes	Price	Source
2	HC-SR501	External PIR modules	$2.00	Octronic
0.43kg	Fiberlogy Easy PET-G pure transparent	Beads filament	$8.55
0.05kg	eSun silver silk PLA	Bar filament	$1.14
98x12cm	Acrylic sheet	Back plate		Waag inventory
90cm	Ribbon cable			Waag inventory
1	Lidl Parkside crimp set		$25	Waag inventory
1	Old USB Cable			My house
1	Power supply		$10	bol.com

Power Requirements

The LED packaging specifies:

Output power: 0.1 W per LED
RGB output current: 5 V 5 mA

The current specification is most likely given per RGB color channel.
Since each LED contains red, green, and blue channels:

Red ≈ 5 mA
Green ≈ 5 mA
Blue ≈ 5 mA

Estimate using the packaging specification:

200 × 0.1 W = 20 W

Required current at 5 V:

20 W ÷ 5 V = 4 A

Measured power consumption

To verify the LED power consumption, a current measurement was performed using 20 LEDs set to full white brightness.

Number of LEDs tested: 20
Supply voltage: 5 V
Measured current: 0.329 A

Current per LED:

0.329 A ÷ 20 = 0.01645 A
≈ 16.5 mA per LED

Power per LED:

5 V × 0.01645 A = 0.08225 W
≈ 0.082 W per LED

Estimated Total System Consumption

The final installation contains approximately 200 LEDs.

Estimated total current:

200 × 16.5 mA = 3300 mA
≈ 3.3 A

Estimated total power consumption:

5 V × 3.3 A = 16.5 W

I ended up buying a 5V 18W charger online.

Fabrication and design research

The design draws inspiration from the 90s classic bead curtain, the aim is not to get the design as close to the original, but it would be nice if the reference is obvious for those whom remember the original all too well. Below I describe what I've learned from during Fab Academy while researching how I would go about making an interactive version of this object.

The OG bead curtain for design reference

Week 5

In week 5 I explored this design direction by making a small 3D-printed bead curtain test. I was interested in the logic of solid beads becoming flexible once connected, and used the assignment to experiment with a faceted bead shape, a rod running through it, and later a simple linked mechanism that could wiggle a bit more like a curtain.

Week 8

In week 8 I learned how to design and produce custom PCBs, which is directly relevant for embedding light into the curtain. I worked on boards that could drive multiple LEDs and got familiar with the full process from schematic to milling and testing. This gave me a better understanding of how to control several light points at once, and how to think about distributing electronics across a system rather than treating it as a single unit.

Week 9

During week 9 I focused on input devices that could be useful for my final project. Unfortunately the magnetic field sensors got delayed in the mail, so for this week I played with a motion and flex sensor instead. For the motion sensor I build a little PCB with a microcontroller socket and a LED that lights up when motion is detected.

Week 10

In week 10 I focused on output devices and explored different types of addressable RGB LEDs for the curtain. Since light is currently the main output for the project, this week was important for understanding both the technical setup and the visual qualities of different LED systems.

I designed and milled a custom PCB that can control multiple LED strands independently, since the final curtain will consist of separate hanging strands rather than one continuous strip. I also experimented with different LED formats and became particularly interested in small “pebble” LEDs, which diffuse light more softly and feel closer to beads hanging in space than flat LED strips do.

Week 15

In week 15 I built a browser-based simulation of the curtain using ThreeJS and the Rapier physics engine. The goal was to prototype the movement and interaction of the final project before building the full physical version.

The simulation models strands of beads with physics-based movement and lets me experiment with different interaction and lighting behaviours. I also used it to prototype the “distress” logic of the curtain, where the light patterns gradually escalate over time until someone passes through.

Click here to open simulation in fullscreen

This week also became an experiment in working with AI-assisted coding. Rather than focusing on polished code structure, I used ChatGPT as a collaborative tool to quickly prototype physics systems, materials, lighting behavior and serial communication with a physical PCB prototype.

Week 16

In week 16 I focused on system integration for the final project.

Inspiration & References

This project is inspired by projects like Random International’s Rain Room, Studio Drift and United Visual Artists and many more. What I find interesting in these works is how they use light and repetition to create a spatial experience you can move through.

Within Fab Academy there are a lot of projects that deal with LEDs, sensors and interaction, usually in the form of panels or wearables. While not directly similar, they were helpful for thinking about how to build a system with multiple light points. Examples include work like Juliana Lozano — Kinetic Curtain, Adriana Mexicano — wearable vest with proximity sensor + LEDs + optical fiber, Nicole Bakker — The Airable, wearable with LED feedback based on sensed data and Diane Walsh — felt artwork + large LED array.

Files

Other ideas

Just cause it's fun, here's some ideas that didn't quite make it:

pimp my cargo bike
hand/body size fidget spinner for my neurodivergent babes, other stimming/pressure devices (or like a wapperman machine?!)
cat doorbell (send to Ricardo Marques)
e-ink keyboard
thermal fax for smartphones
wearable displaying satellite data