initial commit

README.md

@@ -1,2 +1,15 @@
-# FLIP-ESP32-I2C-OLED
-more details to come, a project for making a FLIP fluid simulation with accelerometer + gyro with a cheap OLED and an ESP32 board
+I wanted to make an ESP32 based 128x64 I2C OLED FLIP simulator,
+inspired by:
+https://mitxela.com/projects/fluid-pendant
+
+but with way cheaper and easier components.
+
+It seemse like there's not a huge body of work on this, but I did find this project:
+https://wokwi.com/projects/420908950128021505
+
+(no user information)
+
+
+anyway...documentation will go on my site: https://zeyus.com/
+
+I'm going to use the following components:

fluid.cpp

@@ -0,0 +1,106 @@
+#include <iostream>
+#include <vector>
+#include <chrono>
+#include <cstdlib>
+#include <cmath>
+
+using namespace std;
+
+// Simulation constants
+const int SIM_WIDTH = 64;
+const int SIM_HEIGHT = 32;
+const int NUM_PARTICLES = 100;
+
+struct Particle {
+    double x, y;
+    double vx, vy;
+};
+
+vector<Particle> particles(NUM_PARTICLES);
+
+void initializeParticles() {
+    for (auto& p : particles) {
+        p.x = rand() % SIM_WIDTH;
+        p.y = rand() % (SIM_HEIGHT / 2);
+        p.vx = (rand() % 200 - 100) / 100.0 * 0.7;
+        p.vy = (rand() % 100 - 50) / 100.0;
+    }
+}
+
+void updatePhysics() {
+    const double gravity = 0.15;
+    const double damping = 0.82;
+    const double border = 2.0;
+
+    for (auto& p : particles) {
+        p.vy += gravity;
+        p.x += p.vx;
+        p.y += p.vy;
+
+        // Horizontal boundary collisions
+        if (p.x < border || p.x >= SIM_WIDTH - border) {
+            p.vx = -p.vx * damping;
+            p.x = max(border, min(p.x, SIM_WIDTH - border - 0.1));
+        }
+
+        // Vertical boundary collisions
+        if (p.y < border || p.y >= SIM_HEIGHT - border) {
+            p.vy = -p.vy * damping;
+            p.y = max(border, min(p.y, SIM_HEIGHT - border - 0.1));
+        }
+    }
+}
+
+void drawFrame() {
+    vector<vector<char> > grid(SIM_HEIGHT, vector<char>(SIM_WIDTH, ' '));
+
+    // Plot particles
+    for (const auto& p : particles) {
+        int x = static_cast<int>(p.x);
+        int y = static_cast<int>(p.y);
+        x = max(0, min(SIM_WIDTH - 1, x));
+        y = max(0, min(SIM_HEIGHT - 1, y));
+        grid[y][x] = 'o';
+    }
+
+    // Clear screen and reset cursor
+    cout << "\033[H";
+
+    // Draw grid
+    for (const auto& row : grid) {
+        for (char c : row) {
+            cout << c;
+        }
+        cout << '\n';
+    }
+    cout << flush;
+}
+
+int main() {
+    srand(time(nullptr));
+    initializeParticles();
+    
+    // Hide cursor
+    cout << "\033[?25l";
+
+    auto last_frame = chrono::steady_clock::now();
+    const chrono::milliseconds frame_delay(33);
+
+    try {
+        while (true) {
+            auto now = chrono::steady_clock::now();
+            if (now - last_frame >= frame_delay) {
+                updatePhysics();
+                drawFrame();
+                last_frame = now;
+            }
+        }
+    } catch (...) {
+        // Show cursor before exiting
+        cout << "\033[?25h";
+    }
+
+    // Restore cursor
+    cout << "\033[?25h";
+    return 0;
+}

fluid.py

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+import time
+import random
+import sys
+
+# Simulation constants
+SIM_WIDTH = 128
+SIM_HEIGHT = 64
+NUM_PARTICLES = 200
+GRAVITY = 0.5
+DAMPING = 0.82
+BORDER = 2.0
+FRAME_DELAY = 0.033  # ~30 FPS
+
+class Particle:
+    def __init__(self):
+        self.x = random.uniform(BORDER, SIM_WIDTH - BORDER)
+        self.y = random.uniform(BORDER, SIM_HEIGHT/2 - BORDER)
+        self.vx = random.uniform(-1, 1) * 0.7
+        self.vy = random.uniform(-0.5, 0.5)
+
+def initialize_particles(num_particles):
+    return [Particle() for _ in range(num_particles)]
+
+def update_physics(particles):
+    for p in particles:
+        # Apply gravity
+        p.vy += GRAVITY
+        
+        # Update position
+        p.x += p.vx
+        p.y += p.vy
+
+        # Horizontal boundary collisions
+        if p.x < BORDER or p.x >= SIM_WIDTH - BORDER:
+            p.vx *= -DAMPING
+            p.x = max(BORDER, min(p.x, SIM_WIDTH - BORDER - 0.1))
+
+        # Vertical boundary collisions
+        if p.y < BORDER or p.y >= SIM_HEIGHT - BORDER:
+            p.vy *= -DAMPING
+            p.y = max(BORDER, min(p.y, SIM_HEIGHT - BORDER - 0.1))
+
+def draw_frame(particles):
+    # Initialize empty grid
+    grid = [[' ' for _ in range(SIM_WIDTH)] for _ in range(SIM_HEIGHT)]
+    
+    # Plot particles
+    for p in particles:
+        x = int(p.x)
+        y = int(p.y)
+        if 0 <= x < SIM_WIDTH and 0 <= y < SIM_HEIGHT:
+            grid[y][x] = 'o'
+    
+    # Build frame buffer
+    buffer = []
+    for row in grid:
+        buffer.append(''.join(row))
+    
+    # Clear screen and move cursor to top-left
+    sys.stdout.write('\033[H\033[J')
+    sys.stdout.write('\n'.join(buffer))
+    sys.stdout.flush()
+
+def main():
+    particles = initialize_particles(NUM_PARTICLES)
+    
+    # Hide cursor
+    sys.stdout.write('\033[?25l')
+    sys.stdout.flush()
+
+    try:
+        while True:
+            start_time = time.monotonic()
+            
+            update_physics(particles)
+            draw_frame(particles)
+            
+            # Frame rate control
+            elapsed = time.monotonic() - start_time
+            sleep_time = FRAME_DELAY - elapsed
+            if sleep_time > 0:
+                time.sleep(sleep_time)
+                
+    except KeyboardInterrupt:
+        pass
+    finally:
+        # Show cursor before exiting
+        sys.stdout.write('\033[?25h')
+        sys.stdout.flush()
+
+if __name__ == "__main__":
+    main()

sketch.ino

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+#include <Arduino.h>
+#include <ESP32-HUB75-MatrixPanel-I2S-DMA.h>
+
+// Config
+#define PANEL_RES_X 64
+#define PANEL_RES_Y 32
+#define NUM_PANELS 2
+#define SIM_WIDTH (PANEL_RES_X * NUM_PANELS)
+#define SIM_HEIGHT PANEL_RES_Y
+#define NUM_PARTICLES 100
+#define FIXED_SHIFT 8
+
+typedef int16_t fixed_t;
+#define TO_FIXED(x) ((fixed_t)((x) * (1 << FIXED_SHIFT)))
+#define TO_FLOAT(x) ((float)(x) / (1 << FIXED_SHIFT))
+
+struct Particle {
+  fixed_t x, y;
+  fixed_t vx, vy;
+};
+
+Particle particles[NUM_PARTICLES];
+MatrixPanel_I2S_DMA *dma_display;
+
+/*
+// Wokwi-compatible pin configuration
+HUB75_I2S_CFG::i2s_pins _pins = {
+  .r1 = 25, .g1 = 26, .b1 = 27, 
+  .r2 = 14, .g2 = 12, .b2 = 13, 
+  .a = 23, .b = 19, .c = 5, .d = 17, 
+  .e = -1, // Required for 64x64 panels
+  .lat = 4, .oe = 15, .clk = 16
+};
+*/
+
+// ESP32-S3-WROOM-1 HUB75 Pin Mapping
+HUB75_I2S_CFG::i2s_pins _pins = {
+  .r1 = 1,  .g1 = 2,  .b1 = 3,
+  .r2 = 4,  .g2 = 5,  .b2 = 6,
+  .a = 7,   .b = 8,   .c = 9,
+  .d = 10,  .e = -1,  // 'e' only needed for 64x64 panels
+  .lat = 11, .oe = 12, .clk = 13
+};
+
+// Color palette
+const uint16_t COLORS[] = {
+  0x001F, 0x03FF, 0x07FF, 0x7FE0, 0x7F80, 0xFFE0, 0xFD20, 0xF800
+};
+const int NUM_COLORS = sizeof(COLORS)/sizeof(COLORS[0]);
+
+void setup() {
+
+  HUB75_I2S_CFG mxconfig(
+    PANEL_RES_X,
+    PANEL_RES_Y,
+    NUM_PANELS,
+    _pins,
+    HUB75_I2S_CFG::FM6126A,
+    false,
+    HUB75_I2S_CFG::HZ_10M,
+    true,
+    HUB75_I2S_CFG::SHIFTREG,
+    false,
+    0
+  );
+
+  mxconfig.double_buff = true;
+  dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+  dma_display->begin();
+  dma_display->setBrightness(255);
+
+  // Initialize particles
+  for (int i = 0; i < NUM_PARTICLES; i++) {
+    particles[i].x = TO_FIXED(random(SIM_WIDTH));
+    particles[i].y = TO_FIXED(random(SIM_HEIGHT/2));
+    particles[i].vx = TO_FIXED((random(-100, 100)/100.0) * 0.7);
+    particles[i].vy = TO_FIXED((random(-50, 50)/100.0));
+  }
+}
+
+void updatePhysics() {
+  const fixed_t gravity = TO_FIXED(0.15);
+  const fixed_t damping = TO_FIXED(0.82);
+  const fixed_t border = TO_FIXED(2.0);
+
+  for (int i = 0; i < NUM_PARTICLES; i++) {
+    particles[i].vy += gravity;
+    particles[i].x += particles[i].vx;
+    particles[i].y += particles[i].vy;
+
+    // Boundary collisions
+    if (particles[i].x < border || particles[i].x >= TO_FIXED(SIM_WIDTH) - border) {
+      particles[i].vx = -particles[i].vx * damping;
+      particles[i].x = constrain(particles[i].x, border, TO_FIXED(SIM_WIDTH) - border);
+    }
+    if (particles[i].y < border || particles[i].y >= TO_FIXED(SIM_HEIGHT) - border) {
+      particles[i].vy = -particles[i].vy * damping;
+      particles[i].y = constrain(particles[i].y, border, TO_FIXED(SIM_HEIGHT) - border);
+    }
+  }
+}
+
+void drawParticles() {
+  dma_display->fillScreen(0);
+  
+  for (int i = 0; i < NUM_PARTICLES; i++) {
+    int x = constrain(TO_FLOAT(particles[i].x), 0, SIM_WIDTH-1);
+    int y = constrain(TO_FLOAT(particles[i].y), 0, SIM_HEIGHT-1);
+    
+    // Simplified color selection
+    uint16_t color = COLORS[(abs(particles[i].vx) + abs(particles[i].vy)) % NUM_COLORS];
+    
+    dma_display->drawPixel(x, y, color);
+  }
+}
+
+void loop() {
+  static uint32_t last_frame = 0;
+  const uint32_t frame_time = 33; // ~30 FPS
+
+  if (millis() - last_frame >= frame_time) {
+    updatePhysics();
+    drawParticles();
+    last_frame = millis();
+  }
+}