diff --git a/.github/workflows/deploy-webapp.yml b/.github/workflows/deploy-webapp.yml
new file mode 100644
index 00000000..7c4ac13e
--- /dev/null
+++ b/.github/workflows/deploy-webapp.yml
@@ -0,0 +1,61 @@
+# Simple workflow for deploying WebAssembly app to GitHub Pages
+name: Deploy WebAssembly app to Pages
+
+on:
+  # Runs on pushes targeting the default branch
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  # Single deploy job since we're just deploying
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set Up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.x
+
+      - name: Install Dependencies
+        run: |
+          pip install -r webapp/requirements.txt
+
+      - name: Build the WebAssembly app
+        run: |
+          shinylive export webapp site
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v3
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v2
+        with:
+          # Upload the 'site' directory, where your app has been built
+          path: "site"
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v2
diff --git a/.ruff.toml b/.ruff.toml
index 1cfeeb74..ead4d843 100644
--- a/.ruff.toml
+++ b/.ruff.toml
@@ -26,6 +26,7 @@ ignore = [
 [per-file-ignores]
 "tests/*.py" = ["ALL"]
 ".github/*py" = ["INP001"]
+"webapp/*py" = ["ALL"]
 
 [flake8-pytest-style]
 fixture-parentheses = false
diff --git a/webapp/app.py b/webapp/app.py
new file mode 100644
index 00000000..f99369cb
--- /dev/null
+++ b/webapp/app.py
@@ -0,0 +1,268 @@
+"""Simple web app to visualize brightness over time."""
+
+import math
+
+import matplotlib.pyplot as plt
+import numpy as np
+from shiny import App, render, ui
+
+
+def lerp(x, x1, x2, y1, y2):
+    """Linearly interpolate between two values."""
+    return y1 + (x - x1) * (y2 - y1) / (x2 - x1)
+
+
+def clamp(value: float, minimum: float, maximum: float) -> float:
+    """Clamp value between minimum and maximum."""
+    return max(minimum, min(value, maximum))
+
+
+def find_a_b(x1: float, x2: float, y1: float, y2: float) -> tuple[float, float]:
+    a = (math.atanh(2 * y2 - 1) - math.atanh(2 * y1 - 1)) / (x2 - x1)
+    b = x1 - (math.atanh(2 * y1 - 1) / a)
+    return a, b
+
+
+def scaled_tanh(
+    x: float,
+    a: float,
+    b: float,
+    y_min: float = 0.0,
+    y_max: float = 1.0,
+) -> float:
+    """Apply a scaled and shifted tanh function to a given input."""
+    return y_min + (y_max - y_min) * 0.5 * (math.tanh(a * (x - b)) + 1)
+
+
+def is_closer_to_sunrise_than_sunset(time, sunrise_time, sunset_time):
+    """Return True if the time is closer to sunrise than sunset."""
+    return abs(time - sunrise_time) < abs(time - sunset_time)
+
+
+def brightness_linear(
+    time,
+    sunrise_time,
+    sunset_time,
+    time_light,
+    time_dark,
+    max_brightness,
+    min_brightness,
+):
+    """Calculate the brightness for the 'linear' mode."""
+    closer_to_sunrise = is_closer_to_sunrise_than_sunset(
+        time,
+        sunrise_time,
+        sunset_time,
+    )
+    if closer_to_sunrise:
+        brightness = lerp(
+            time,
+            x1=sunrise_time - time_dark,
+            x2=sunrise_time + time_light,
+            y1=min_brightness,
+            y2=max_brightness,
+        )
+    else:
+        brightness = lerp(
+            time,
+            x1=sunset_time - time_light,
+            x2=sunset_time + time_dark,
+            y1=max_brightness,
+            y2=min_brightness,
+        )
+    return clamp(brightness, min_brightness, max_brightness)
+
+
+def brightness_tanh(
+    time,
+    sunrise_time,
+    sunset_time,
+    time_light,
+    time_dark,
+    max_brightness,
+    min_brightness,
+):
+    """Calculate the brightness for the 'tanh' mode."""
+    closer_to_sunrise = is_closer_to_sunrise_than_sunset(
+        time,
+        sunrise_time,
+        sunset_time,
+    )
+    if closer_to_sunrise:
+        a, b = find_a_b(
+            x1=-time_dark,
+            x2=time_light,
+            y1=0.05,  # be at 5% of range at x1
+            y2=0.95,  # be at 95% of range at x2
+        )
+        brightness = scaled_tanh(
+            time - sunrise_time,
+            a=a,
+            b=b,
+            y_min=min_brightness,
+            y_max=max_brightness,
+        )
+    else:
+        a, b = find_a_b(
+            x1=-time_light,  # shifted timestamp for the start of sunset
+            x2=time_dark,  # shifted timestamp for the end of sunset
+            y1=0.95,  # be at 95% of range at the start of sunset
+            y2=0.05,  # be at 5% of range at the end of sunset
+        )
+        brightness = scaled_tanh(
+            time - sunset_time,
+            a=a,
+            b=b,
+            y_min=min_brightness,
+            y_max=max_brightness,
+        )
+    return clamp(brightness, min_brightness, max_brightness)
+
+
+SEC_PER_HR = 60 * 60
+
+# Shiny UI
+app_ui = ui.page_fluid(
+    ui.layout_sidebar(
+        ui.panel_sidebar(
+            ui.input_slider("min_brightness", "min_brightness", 0, 100, 30, post="%"),
+            ui.input_slider("max_brightness", "max_brightness", 0, 100, 100, post="%"),
+            ui.input_slider(
+                "dark_time",
+                "brightness_mode_time_dark",
+                0,
+                5 * SEC_PER_HR,
+                3 * SEC_PER_HR,
+                post=" sec",
+            ),
+            ui.input_slider(
+                "light_time",
+                "brightness_mode_time_light",
+                0,
+                5 * SEC_PER_HR,
+                0.5 * SEC_PER_HR,
+                post=" sec",
+            ),
+            ui.input_slider(
+                "sunrise_time",
+                "sunrise_time",
+                0,
+                24,
+                6,
+                step=0.5,
+                post=" hr",
+            ),
+            ui.input_slider(
+                "sunset_time",
+                "sunset_time",
+                0,
+                24,
+                18,
+                step=0.5,
+                post=" hr",
+            ),
+        ),
+        ui.panel_main(ui.output_plot(id="brightness_plot")),
+    ),
+)
+
+
+def server(input, output, session):
+    @output
+    @render.plot
+    def brightness_plot():
+        return plot_brightness(
+            min_brightness=input.min_brightness() / 100,
+            max_brightness=input.max_brightness() / 100,
+            brightness_mode_time_dark=input.dark_time() / SEC_PER_HR,
+            brightness_mode_time_light=input.light_time() / SEC_PER_HR,
+            sunrise_time=input.sunrise_time(),
+            sunset_time=input.sunset_time(),
+        )
+
+
+def plot_brightness(
+    min_brightness,
+    max_brightness,
+    brightness_mode_time_dark,
+    brightness_mode_time_light,
+    sunrise_time=6,  # 6 AM
+    sunset_time=18,  # 6 PM
+):
+    # Define the time range for our simulation
+    time_range = np.linspace(0, 24, 1000)  # From 0 to 24 hours
+
+    # Calculate the brightness for each time in the time range for both modes
+    brightness_linear_values = [
+        brightness_linear(
+            time,
+            sunrise_time,
+            sunset_time,
+            brightness_mode_time_light,
+            brightness_mode_time_dark,
+            max_brightness,
+            min_brightness,
+        )
+        for time in time_range
+    ]
+    brightness_tanh_values = [
+        brightness_tanh(
+            time,
+            sunrise_time,
+            sunset_time,
+            brightness_mode_time_light,
+            brightness_mode_time_dark,
+            max_brightness,
+            min_brightness,
+        )
+        for time in time_range
+    ]
+
+    # Plot the brightness over time for both modes
+    plt.figure(figsize=(10, 6))
+    plt.plot(time_range, brightness_linear_values, label="Linear Mode")
+    plt.plot(time_range, brightness_tanh_values, label="Tanh Mode")
+    plt.vlines(sunrise_time, 0, 1, color="C2", label="Sunrise", linestyles="dashed")
+    plt.vlines(sunset_time, 0, 1, color="C3", label="Sunset", linestyles="dashed")
+    plt.xlim(0, 24)
+    plt.xticks(np.arange(0, 25, 1))
+    yticks = np.arange(0, 1.05, 0.05)
+    ytick_labels = [f"{100*label:.0f}%" for label in yticks]
+    plt.yticks(yticks, ytick_labels)
+    plt.xlabel("Time (hours)")
+    plt.ylabel("Brightness")
+    plt.title("Brightness over Time for Different Modes")
+
+    # Add text box
+    textstr = "\n".join(
+        (
+            f"Sunrise Time = {sunrise_time}:00:00",
+            f"Sunset Time = {sunset_time}:00:00",
+            f"Max Brightness = {max_brightness*100:.0f}%",
+            f"Min Brightness = {min_brightness*100:.0f}%",
+            f"Time Light = {brightness_mode_time_light:.1f} hours",
+            f"Time Dark = {brightness_mode_time_dark:.1f} hours",
+        ),
+    )
+
+    # these are matplotlib.patch.Patch properties
+    props = {"boxstyle": "round", "facecolor": "wheat", "alpha": 0.5}
+
+    plt.legend()
+    plt.grid(True)
+
+    # place a text box in upper left in axes coords
+    plt.gca().text(
+        0.4,
+        0.55,
+        textstr,
+        transform=plt.gca().transAxes,
+        fontsize=10,
+        verticalalignment="center",
+        bbox=props,
+    )
+
+    return plt.gcf()
+
+
+app = App(app_ui, server)
diff --git a/webapp/requirements.txt b/webapp/requirements.txt
new file mode 100644
index 00000000..f832a57a
--- /dev/null
+++ b/webapp/requirements.txt
@@ -0,0 +1 @@
+shinylive