Listening to the Gut: A Sensory Feedback System
1. 🔍 Background: A Gut Feeling
2. 🌡️ Building the Bioreactor: Keeping the Gut Alive
3. 🎨 Embodiment and Design
4. 🔧 Dividing elements: Sound, Light, Movement
4.1 ⚙️ Power and Control: Fan Experiments
4.2 Piezo function and experimentation
5. 🔄 Integration: Code, Logic, and Interactions
6. 🌀 Reflections and Next Steps

Published May 27, 2025

Gut-Gut Connection

A sensory device that listens to your gut—literally—triggering light, wind, and flow in response to your body’s subtle signals.

BeginnerFull instructions provided10 hours125

Things used in this project

Hardware components

Arduino UNO

ControlEverything.com Piezo Sensor

Axial Fan, 12 VDC

Rotary potentiometer (generic)

Power MOSFET N-Channel

1N4007 – High Voltage, High Current Rated Diode

Resistor 220 ohm

SparkFun LilyPad Rainbow LED (strip of 7 colors)

air pump

Software apps and online services

Arduino IDE

Autodesk Fusion

Hand tools and fabrication machines

3D Printer (generic)

Story

Listening to the Gut: A Sensory Feedback System

1. 🔍 Background: A Gut Feeling

This project was born from a desire to connect more intimately with the often-overlooked intelligence of the gut. In many cultures and recent science, the gut is referred to as the "second brain"—responsible not only for digestion, but also for emotion, immunity, intuition, and instinct. I was fascinated by this idea, and wondered: what would it look like to design a system that listens to the gut and reacts in real-time, making the invisible visible?

This inquiry guided the development of a multi-sensory installation that could respond to subtle bodily signals, emphasizing presence and awareness. I wanted the system to feel alive and reactive—not just visually, but through touch and movement as well. The first goal was not to measure the gut’s data, but to care for it. That’s when the concept of a bioreactor emerged.

2. 🌡️ Building the Bioreactor: Keeping the Gut Alive

The core of this project was a living system—a vessel designed to keep gut bacteria alive. The idea was to build a bioreactor to maintain and cultivate a twin of my gut bacteria under controlled conditions.

I envisioned the bioreactor as a transparent belly, a semi-living object that breathes, flows, and reacts. To create this, I needed basic elements:

a stable container, aeration mechanisms (air pump), fluid movement (enabled by a DIY stirrer), and sensory input and output to reflect the system's state.

The initial housing was a simple jar wrapped in heating and airflow systems. But the ultimate aim was symbiosis—the human provides signals (touch, presence), and the gut responds.

3. 🎨 Embodiment and Design

With the knowledge of which components I will be using, I started working on a simple 3D model of the casing for the electrical components and a barrier for the fan with magnets to hold on to.

4. 🔧 Dividing elements: Sound, Light, Movement

The first step was identifying an input from the body that was accessible yet meaningful. I chose to work with a piezo sensor, typically used to detect vibration or pressure, which could pick up the low-frequency rumbles from the abdomen. I imagined these internal gurgles and pulses as data waiting to be transformed into color, andair movement.

Alongside the piezo, I incorporated a NeoPixel LED strip to visualize the intensity of vibrations in magenta hues—a color chosen for its visceral yet ethereal feel.

To make the feedback multi-modal, I added a small 5V fan (symbolizing breath or wind in the belly) and a relay-controlled water pump to represent gut fluidity and flow.

4.1 ⚙️ Power and Control: Fan Experiments

Controlling the fan turned out to be more complicated than expected. Initially, I tried powering it directly from the Arduino using PWM, but the fan required more current than the Arduino could supply. I then used a 5V external power supply, a PN2222 NPN transistor, and later a MOSFET to drive the fan safely with PWM control.

I mapped the potentiometer readings to the fan's speed, allowing users to adjust the intensity of the wind. Interestingly, the fan wouldn't start below 5V, so I had to recalibrate the control range to reflect its working threshold.

4.2 Piezo function and experimentation

In order to capture the sound of the gut, I tried a couple times to play with the code and hardware of the piezo. I found that sometimes the piezo, was too sensitive and had to be adjusted with code. Or not sensitive enough. In the end the contraption that I had had a weird threshold, meaning that if it detected a high noise, it remained less sensible. I did a sort of insulation element in order for the piezo to be as stable as possible using cardboard and foam. This turned out to be a good solution.

5. 🔄 Integration: Code, Logic, and Interactions

The core loop began to take shape:

The piezo sensor continuously read analog vibration values.
Values above a certain threshold triggered an increase in LED brightness, which would then fade slowly.
The push button acted as a mode switch—when pressed, it turned on the relay for the pump and allowed PWM fan control.
A potentiometer scaled the fan speed based on user preference.

The code brought all elements together, and it finally felt like the gut had a voice—or at least a glow, a breath, and a flow.

6. 🌀 Reflections and Next Steps

Building this project was both deeply technical and metaphorical. It taught me to figure out ways in which I can listen to my body both through technology, but also with my body itself. Each problem became a moment of reflection.

Next steps include:

Replacing the piezo with a more accurate contact microphone or stomach EMG

Replacing the piezo with a more accurate contact microphone or stomach EMG
Making the setup wearable (a belt or abdominal interface)
Creating a networked version where multiple people’s guts can be in dialogue

Ultimately, this project is about slowing down, tuning in, and creating artifacts that encourage bodily awareness in a technological world.

Code

Combined Sensors

#include <Adafruit_NeoPixel.h>

#define TOUCH_PIN 2
#define PIEZO_PIN A0
#define POT_PIN A1
#define RELAY_PIN 7
#define FAN_PWM_PIN 5
#define LED_PIN 6
#define NUMPIXELS 10

Adafruit_NeoPixel pixels(NUMPIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  pinMode(TOUCH_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(FAN_PWM_PIN, OUTPUT);
  pixels.begin();
  Serial.begin(9600);
}

void loop() {
  int piezoValue = analogRead(PIEZO_PIN);
  int potValue = analogRead(POT_PIN);
  int mappedPot = map(potValue, 0, 1023, 0, 255);
  bool buttonPressed = digitalRead(TOUCH_PIN) == HIGH;

  if (buttonPressed) {
    digitalWrite(RELAY_PIN, HIGH);
    analogWrite(FAN_PWM_PIN, mappedPot);
  } else {
    digitalWrite(RELAY_PIN, LOW);
    analogWrite(FAN_PWM_PIN, 0);
  }

  // LED response to gut signal
  int brightness = map(piezoValue, 0, 1023, 0, 255);
  for (int i = 0; i < NUMPIXELS; i++) {
    pixels.setPixelColor(i, pixels.Color(brightness, 0, brightness)); // Magenta
  }
  pixels.show();

  delay(50);
}