intangible interaction
Proximity Sensor Research
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