diff --git a/README.md b/README.md
index 2023e68..b744273 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,45 @@
-# filament-drybox-cost
+# Filament Drybox Cost Model
-Ascertain the out-of-pocket costs to create one or more dryboxes.
\ No newline at end of file
+20260319 ChatGPT
+$Header$
+
+## Purpose
+
+This project provides a transparent and reproducible cost model for the
+"Filament Storage 2026" drybox project by GunplaMark.
+
+The model is intended to answer questions such as:
+
+- What is the out-of-pocket cost to build 1 drybox?
+- How does the per-unit cost change when building 4 dryboxes?
+- How does the per-unit cost change when building 12 dryboxes?
+- What inventory remains after each build scenario?
+- How much do filament and electricity contribute to the total?
+
+The model accounts for:
+
+- lot-based purchasing
+- per-box usage
+- printed part filament cost
+- electrical cost of printing
+- optional waste factor
+
+See video at https://youtu.be/lJDoVH7qTKs?si=cQMhUda7RQcuIDJU by user GunplaMark entitled "Filament Storage 2026 - The Final Boss of My Drybox Journey".
+
+
+## Repository Layout
+
+```text
+.
+├── LICENSE
+├── README.md
+├── data
+│ ├── assumptions.json
+│ └── bom.json
+├── export
+├── tools
+│ └── generate_csv.pl
+└── web
+ ├── app.js
+ ├── index.html
+ └── style.css
diff --git a/data/assumptions.json b/data/assumptions.json
new file mode 100644
index 0000000..0f75eab
--- /dev/null
+++ b/data/assumptions.json
@@ -0,0 +1,33 @@
+{
+ "currency": "USD",
+ "waste_factor": 1.15,
+ "electricity_cost_per_kwh": 0.12,
+ "printer_average_watts": 120,
+ "print_hours_per_box": 8.0,
+ "target_box_counts": [1, 4, 12],
+ "printed_materials": [
+ {
+ "id": "petg",
+ "name": "PETG",
+ "cost_per_kg": 22.00,
+ "grams_per_box": 220
+ },
+ {
+ "id": "asa",
+ "name": "ASA",
+ "cost_per_kg": 28.00,
+ "grams_per_box": 90
+ },
+ {
+ "id": "tpu",
+ "name": "TPU",
+ "cost_per_kg": 26.00,
+ "grams_per_box": 20
+ }
+ ],
+ "notes": [
+ "Printed weights are initial estimates and should later be replaced with slicer-derived actuals.",
+ "Waste factor is applied to printed material cost only.",
+ "Electricity uses printer_average_watts multiplied by print_hours_per_box."
+ ]
+}
diff --git a/data/bom.json b/data/bom.json
new file mode 100644
index 0000000..41691db
--- /dev/null
+++ b/data/bom.json
@@ -0,0 +1,85 @@
+{
+ "project_name": "Filament Drybox Cost Model",
+ "source_model": "Filament Storage 2026 by GunplaMark",
+ "source_url": "https://www.printables.com/",
+ "currency": "USD",
+ "components": [
+ {
+ "id": "container",
+ "name": "4L cereal container",
+ "category": "hardware",
+ "unit_type": "each",
+ "pack_qty": 4,
+ "pack_cost": 39.99,
+ "units_used_per_box": 1,
+ "optional": false,
+ "notes": "Praki, Wildone, or Skroam style 4L container"
+ },
+ {
+ "id": "bearing",
+ "name": "608 bearing",
+ "category": "hardware",
+ "unit_type": "each",
+ "pack_qty": 10,
+ "pack_cost": 11.99,
+ "units_used_per_box": 4,
+ "optional": false,
+ "notes": "Open, ungreased fidget-spinner style bearings"
+ },
+ {
+ "id": "badge_reel",
+ "name": "badge reel",
+ "category": "hardware",
+ "unit_type": "each",
+ "pack_qty": 10,
+ "pack_cost": 14.99,
+ "units_used_per_box": 1,
+ "optional": false,
+ "notes": "Used to harvest spring"
+ },
+ {
+ "id": "foam_cord",
+ "name": "3mm silicone foam cord",
+ "category": "consumable",
+ "unit_type": "meter",
+ "pack_qty": 10,
+ "pack_cost": 9.99,
+ "units_used_per_box": 0.70,
+ "optional": false,
+ "notes": "Length per box is an estimate; measure actual lid circumference"
+ },
+ {
+ "id": "desiccant",
+ "name": "activated alumina desiccant",
+ "category": "consumable",
+ "unit_type": "gram",
+ "pack_qty": 2000,
+ "pack_cost": 24.99,
+ "units_used_per_box": 150,
+ "optional": false,
+ "notes": "Silica gel could be modeled as an alternative later"
+ },
+ {
+ "id": "hygrometer",
+ "name": "rectangular hygrometer",
+ "category": "hardware",
+ "unit_type": "each",
+ "pack_qty": 4,
+ "pack_cost": 17.99,
+ "units_used_per_box": 1,
+ "optional": false,
+ "notes": "Common small rectangular hygrometer"
+ },
+ {
+ "id": "nfc_tag",
+ "name": "25mm NFC tag",
+ "category": "optional",
+ "unit_type": "each",
+ "pack_qty": 20,
+ "pack_cost": 9.99,
+ "units_used_per_box": 1,
+ "optional": true,
+ "notes": "Optional spool identification tag"
+ }
+ ]
+}
diff --git a/tools/generate_cvs.pl b/tools/generate_cvs.pl
new file mode 100755
index 0000000..b27de50
--- /dev/null
+++ b/tools/generate_cvs.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/perl
+#
+# Example command lines:
+#
+# perl generate_csv.pl
+#
+# 20260319 ChatGPT
+# $Header$
+#
+# Purpose:
+# Placeholder script for later CSV export from the BOM and assumptions data.
+#
+
+use strict;
+use warnings;
+
+print "generate_csv.pl: placeholder script\n";
+print "Later revision will read ../data/bom.json and ../data/assumptions.json\n";
+print "and produce a CSV summary under ../export/.\n";
+
+exit 0;
diff --git a/web/app.js b/web/app.js
new file mode 100644
index 0000000..c592037
--- /dev/null
+++ b/web/app.js
@@ -0,0 +1,249 @@
+/*
+20260319 ChatGPT
+$Header$
+*/
+
+"use strict";
+
+function currency(value) {
+ return new Intl.NumberFormat("en-US", {
+ style: "currency",
+ currency: "USD"
+ }).format(value);
+}
+
+function ceilDivUsage(requiredUnits, packQty) {
+ return Math.ceil(requiredUnits / packQty);
+}
+
+function computePrintingCost(assumptions, boxCount) {
+ let materialCost = 0;
+
+ for (const material of assumptions.printed_materials) {
+ const totalGrams = material.grams_per_box * boxCount;
+ const totalKg = totalGrams / 1000.0;
+ materialCost += totalKg * material.cost_per_kg;
+ }
+
+ materialCost *= assumptions.waste_factor;
+
+ const totalKwh =
+ (assumptions.printer_average_watts / 1000.0) *
+ assumptions.print_hours_per_box *
+ boxCount;
+
+ const electricityCost = totalKwh * assumptions.electricity_cost_per_kwh;
+
+ return {
+ material_cost: materialCost,
+ electricity_cost: electricityCost,
+ total_printing_cost: materialCost + electricityCost
+ };
+}
+
+function computeHardwareScenario(bom, boxCount, includeOptional = true) {
+ const componentRows = [];
+ let totalHardwareCost = 0;
+
+ for (const component of bom.components) {
+ if (!includeOptional && component.optional) {
+ continue;
+ }
+
+ const requiredUnits = component.units_used_per_box * boxCount;
+ const packsRequired = ceilDivUsage(requiredUnits, component.pack_qty);
+ const purchasedUnits = packsRequired * component.pack_qty;
+ const leftoverUnits = purchasedUnits - requiredUnits;
+ const totalCost = packsRequired * component.pack_cost;
+
+ totalHardwareCost += totalCost;
+
+ componentRows.push({
+ id: component.id,
+ name: component.name,
+ required_units: requiredUnits,
+ pack_qty: component.pack_qty,
+ pack_cost: component.pack_cost,
+ packs_required: packsRequired,
+ purchased_units: purchasedUnits,
+ leftover_units: leftoverUnits,
+ total_cost: totalCost,
+ optional: component.optional,
+ unit_type: component.unit_type,
+ notes: component.notes
+ });
+ }
+
+ return {
+ box_count: boxCount,
+ total_hardware_cost: totalHardwareCost,
+ component_rows: componentRows
+ };
+}
+
+function renderAssumptions(assumptions) {
+ const div = document.getElementById("assumptions");
+
+ const materialLines = assumptions.printed_materials.map((m) => {
+ return `${m.name}: ${m.grams_per_box} g/box at ${currency(m.cost_per_kg)}/kg `;
+ }).join("");
+
+ div.innerHTML = `
+
+ Waste factor: ${assumptions.waste_factor}
+ Electricity: ${currency(assumptions.electricity_cost_per_kwh)}/kWh
+ Printer average load: ${assumptions.printer_average_watts} W
+ Print hours per box: ${assumptions.print_hours_per_box}
+ Target scenarios: ${assumptions.target_box_counts.join(", ")}
+
+ Printed materials
+
+ `;
+}
+
+function renderSummaryTable(bom, assumptions) {
+ const tbody = document.querySelector("#summary-table tbody");
+ tbody.innerHTML = "";
+
+ for (const boxCount of assumptions.target_box_counts) {
+ const hardware = computeHardwareScenario(bom, boxCount, true);
+ const printing = computePrintingCost(assumptions, boxCount);
+ const totalCost = hardware.total_hardware_cost + printing.total_printing_cost;
+ const costPerBox = totalCost / boxCount;
+
+ const tr = document.createElement("tr");
+ tr.innerHTML = `
+ ${boxCount}
+ ${currency(hardware.total_hardware_cost)}
+ ${currency(printing.total_printing_cost)}
+ ${currency(totalCost)}
+ ${currency(costPerBox)}
+ `;
+ tbody.appendChild(tr);
+ }
+}
+
+function renderComponentBreakdowns(bom, assumptions) {
+ const container = document.getElementById("component-breakdowns");
+ container.innerHTML = "";
+
+ for (const boxCount of assumptions.target_box_counts) {
+ const hardware = computeHardwareScenario(bom, boxCount, true);
+
+ const section = document.createElement("div");
+ section.className = "scenario-block";
+
+ let rowsHtml = "";
+ for (const row of hardware.component_rows) {
+ rowsHtml += `
+
+ ${row.name}${row.optional ? " (optional)" : ""}
+ ${row.required_units}
+ ${row.pack_qty}
+ ${currency(row.pack_cost)}
+ ${row.packs_required}
+ ${currency(row.total_cost)}
+ ${row.notes || ""}
+
+ `;
+ }
+
+ section.innerHTML = `
+ ${boxCount} box${boxCount === 1 ? "" : "es"}
+
+
+
+ Component
+ Required Units
+ Pack Qty
+ Pack Cost
+ Packs Required
+ Total Cost
+ Notes
+
+
+
+ ${rowsHtml}
+
+
+ `;
+
+ container.appendChild(section);
+ }
+}
+
+function renderLeftovers(bom, assumptions) {
+ const container = document.getElementById("leftovers");
+ container.innerHTML = "";
+
+ for (const boxCount of assumptions.target_box_counts) {
+ const hardware = computeHardwareScenario(bom, boxCount, true);
+
+ const section = document.createElement("div");
+ section.className = "scenario-block";
+
+ let rowsHtml = "";
+ for (const row of hardware.component_rows) {
+ rowsHtml += `
+
+ ${row.name}
+ ${row.purchased_units}
+ ${row.required_units}
+ ${row.leftover_units}
+ ${row.unit_type}
+
+ `;
+ }
+
+ section.innerHTML = `
+ ${boxCount} box${boxCount === 1 ? "" : "es"}
+
+
+
+ Component
+ Purchased Units
+ Used Units
+ Leftover Units
+ Unit Type
+
+
+
+ ${rowsHtml}
+
+
+ `;
+
+ container.appendChild(section);
+ }
+}
+
+async function loadJson(url) {
+ const response = await fetch(url);
+ if (!response.ok) {
+ throw new Error(`Failed to load ${url}: ${response.status}`);
+ }
+ return await response.json();
+}
+
+async function main() {
+ try {
+ const bom = await loadJson("../data/bom.json");
+ const assumptions = await loadJson("../data/assumptions.json");
+
+ renderAssumptions(assumptions);
+ renderSummaryTable(bom, assumptions);
+ renderComponentBreakdowns(bom, assumptions);
+ renderLeftovers(bom, assumptions);
+ } catch (err) {
+ console.error(err);
+ document.body.innerHTML = `
+
+ Error
+ Unable to load project data.
+ ${String(err)}
+
+ `;
+ }
+}
+
+main();
diff --git a/web/index.html b/web/index.html
new file mode 100644
index 0000000..8cac54b
--- /dev/null
+++ b/web/index.html
@@ -0,0 +1,89 @@
+
+
+
+
+ Filament Drybox Cost Model
+
+ Filament Drybox Cost Model
+
+ Lot-based purchasing, filament cost, and electricity for 1, 4, and 12 dryboxes
+
+
+
+
+
+ Overview
+
+ This page estimates the out-of-pocket cost of building filament dryboxes,
+ taking into account both purchased hardware sold in lots and the printing
+ cost of the required parts.
+
+
+
+
+
+
+ Summary
+
+
+
+ Boxes
+ Total Hardware
+ Total Printing
+ Total Cost
+ Cost / Box
+
+
+
+
+
+
+ Component Breakdown
+
+
+
+
+ Inventory Leftovers
+
+
+
+
+ Notes
+
+ Hardware pricing is modeled using whole-pack purchases.
+ Printed material pricing is based on estimated grams per box.
+ Electricity is based on average printer wattage over total print time.
+ All initial prices and print weights should be revised with measured values.
+
+
+
+
+
+
+
+
+
diff --git a/web/style.css b/web/style.css
new file mode 100644
index 0000000..135a027
--- /dev/null
+++ b/web/style.css
@@ -0,0 +1,75 @@
+/*
+20260319 ChatGPT
+$Header$
+*/
+
+body {
+ font-family: Arial, Helvetica, sans-serif;
+ margin: 0;
+ padding: 0;
+ background: #f4f6f8;
+ color: #222;
+}
+
+header,
+footer {
+ background: #1f2933;
+ color: #fff;
+ padding: 1rem 1.5rem;
+}
+
+header h1,
+footer p {
+ margin: 0;
+}
+
+.subtitle {
+ margin-top: 0.5rem;
+ color: #d9e2ec;
+}
+
+main {
+ max-width: 1100px;
+ margin: 1.5rem auto;
+ padding: 0 1rem;
+}
+
+.card {
+ background: #fff;
+ border: 1px solid #d9e2ec;
+ border-radius: 8px;
+ padding: 1rem 1.25rem;
+ margin-bottom: 1rem;
+ box-shadow: 0 1px 3px rgba(0,0,0,0.06);
+}
+
+table {
+ width: 100%;
+ border-collapse: collapse;
+ margin-top: 0.5rem;
+}
+
+th,
+td {
+ border: 1px solid #cbd2d9;
+ padding: 0.55rem 0.7rem;
+ text-align: left;
+ vertical-align: top;
+}
+
+th {
+ background: #e9eff5;
+}
+
+.scenario-block {
+ margin-bottom: 1.5rem;
+}
+
+.small-note {
+ color: #52606d;
+ font-size: 0.92rem;
+}
+
+.mono {
+ font-family: "Courier New", Courier, monospace;
+}