intangible interaction
Proximity Sensor Research
Curious Cube
Intangible Interaction Among Us
w/ Seeha Park
Jan 23rd, 2026
1) Observation
In the case of sound-reactive light, we use implicit interaction design framework to analyze the system.
reactive to motion
common error: duration of light depends on motion rather than presence
→ light will turn off even when present
vs. sound
common error: detection of sound through volume(decibels)
→ difficulty differentiating between human and non-human sounds, and light will turn off even when present
2) Research:
Motion:
Instruction Manual: WIRELESS 3 IN 1 LED NIGHT LIGHT
ㄴ mostly listed as “motion sensor” without any specifications
ㄴ most likely to be proximity sensor, such as ToF
Sound:
ㄴ High Pass Filter Frequency
ㄴ Audio Input Signal Gain
3) Ideation
stage/performance design such as haunted house
By programing a delay between interaction and reaction, either reacting to motion or sound, one can create a horror ambience.
Proximity Sensor Research
w/ Matt, Seeha, Jisoo
Jan 29, 2026
LIDAR-Lite V3HP Laser Ranging Module
LIDAR stands for Light Detection and Ranging. Basically, it shoots a laser beam at something and measures how long it takes for the light to bounce back. Since light travels stupid fast (like 186,000 miles per second), the sensor needs some seriously precise timing to figure out distances.
The cool thing compared to ultrasonic sensors is that LIDAR doesn't care about echoes or weird room acoustics. And unlike basic IR sensors that just tell you "something's kinda close," LIDAR gives you actual distance measurements in centimeters.
Sensing Angle
This is a focused point LIDAR, meaning it measures along a single narrow beam instead of scanning a wide area. The beam divergence is 8 milliradians, which works out to roughly 0.46 degrees. Super narrow! The laser spot gets about 8mm wider for every meter of distance, so at max range (40m) you're looking at a spot around 32cm across.
Distance Range
| What | How Much |
|---|---|
| Minimum Range | Around 5cm (gets weird below 30cm) |
| Maximum Range | 40 meters (spec), ~20 meters (stable in our tests) |
| Resolution | 1 cm |
| Accuracy | Plus or minus 2.5 cm beyond 2 meters |
Note: While Garmin specs say 40m, in our actual experiments we found the stable reliable max was around 20 meters. Beyond that, readings started getting flaky. Your mileage may vary depending on lighting conditions and target surface.
Also worth noting: when an object is out of range, the sensor returns 0. So if you're seeing 0cm readings, it doesn't mean something is touching the sensor, it means there's nothing within detectable range.
Speed
It can pump out over 1000 measurements per second. The older V3 maxed out at 500Hz, so this thing is literally twice as fast. That matters a lot if you're tracking something moving quickly.
The Boring But Important Stuff
| Spec | Value |
|---|---|
| Voltage | 4.75 to 5V (don't go over 6V!) |
| Power Draw (idle) | 65 mA |
| Power Draw (measuring) | 85 mA |
| Laser Wavelength | 905 nm (infrared, you can't see it) |
| Weight | 34 grams |
| Size | 24.5 x 53.5 x 33.5 mm |
| Waterproof Rating | IPX7 |
| Communication | I2C or PWM |
Oh and it's a Class 1 laser, which means it's eye safe under normal use. So you won't accidentally blind yourself, which is nice.
How This Thing Actually Works
The sensor has two tubes on the front. One shoots out the laser pulse, the other catches it when it bounces back. Here's the basic flow:
Step 1: Laser pulse goes out through the transmitter tube
Step 2: Hits whatever you're pointing at
Step 3: Bounces back to the receiver tube
Step 4: Calculates the round trip time
Step 5: Get a distance in centimeters
What People Actually Use These For
- Drones. Altitude hold, terrain following, obstacle avoidance, precision landing. The low weight and long range make it perfect.
- Robots. Navigation, obstacle detection, measuring distances for grabbing stuff.
- DIY 3D Scanners. Mount it on a pan tilt mechanism, sweep it around, collect points, boom you've got a point cloud.
- Autonomous vehicles. Ground proximity and obstacle sensing for unmanned ground vehicles.
Other Sensors in the class
VL53L0X: ToF (Longer range)
APDS9960: Proximity, Light, RGB, and Gesture Sensor
Mini PIR: Passive infrared sensor
Presence Sensor
Curious Cube
Feb 3 - Mar 10
What is it?
QQQ is a soft musical interface. From outside, it’s an adorable, fluffy cube, but the “inner part” is a little evil. It will make unpleasant noise when you move it around.
With a strap, it could also be a wearable instrument that considers the body as the “wall”.
Inspiration
The inspiration came from the world’s first electronic instrument—the Theremin. I did a prototype Theremin experiment in my pcomp class last semester, and I also wanted to make a soft instrument. So a simple idea came up: use two proximity sensors on the front and side faces of the cube. If you place the cube into an open box, the two sensors can detect the (x, y) position and make different sounds based on the distance from the walls.
555 Timer
Another thing I wanted to experiment with is analog circuits. I used two 555 timers in my circuit and two IR sensors that control the pitch and the tempo. The first sensor that came to my mind was the ToF sensor, which is a digital sensor, not an analog sensor. So I pivoted to an IR sensor because it outputs analog data. You can consider it a variable voltage.
Pin 5 on the 555 timer is the control voltage pin. I connected the Vo pin (voltage output) of the IR sensor to Pin 5 (you can check this in my schematic). To connect the two 555 timers, I connected one timer’s reset pin (Pin 4) to the other timer’s output pin (Pin 3).
IR Sensor
In my first test (using a single 555 for tempo change), I found the result to be less obvious for tempo changes (I should have tested pitch first), which slowed me down quite a bit. I read the datasheet of the GP2Y0A41SK0F, a short-range IR sensor. After that, I started to add the pitch part into my circuit, and it turned out that the pitch change is much more obvious compared to tempo, which made me happy.
Besides building the circuit, I observed something interesting: both pitch and tempo are not linear when I move the cube linearly. I looked at the datasheet again and found that the output voltage follows a curve, with a peak at 4 cm. So one of the tasks I asked the class to do was to find its lowest and slowest position. The answer is obvious if you look at the datasheet—it’s 4 cm by 4 cm.
Enclosure Design
I’ve always wanted to combine my hobbies with my professional practice, and I finally decided to do that in this project. I had the idea of making a soft instrument last semester, but it was just in my head. In this case, I decided to crochet the cover of my 3D-printed enclosure, which can also be considered the solid structure.
The first cube I made had less consideration. I didn’t think about the mounting parts for both the speaker and the IR sensors, and honestly, it was a little too big. I wanted it to be as compact as possible. So I learned how to model and print a single test part for the cube so that I didn’t have to wait 12 hours to print a full cube just to see if the components would fit. But things happened anyway. It turned out that the test part was printed upright, but in the actual cube case it is the facade, so it condensed a little bit because of gravity. It still worked with screws—or maybe even better—but it wasn’t what I expected.
My next step is to add a switch to the circuit so that I don’t have to open the cube and plug in the battery every time I want to show people this project. Or maybe I should also use a motion detection sensor. Then whenever you move the cube, it will make noisy sounds! :)))) FUN!