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Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

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+# Altium Scripts
+
+## Capacitors by net pair
+
+**Script:** `CapacitorsByNetPair.pas`
+
+Finds all **two-pad components** on the PCB that share the same two nets (e.g. decoupling capacitors between VCC and GND). Outputs a JSON file with:
+
+- **Key:** net pair (e.g. `"GND|VCC"`), sorted so the same pair is always grouped
+- **Value:** for each net pair:
+  - List of capacitors: designator, value string, package (footprint), and capacitance in farads
+  - **Total capacitance** for that net pair (sum of all caps between those two nets)
+
+### How to run
+
+1. Open your **PcbDoc** in Altium Designer.
+2. **DXP → Run Script…** (or **File → Run Script…** depending on version).
+3. Browse to `CapacitorsByNetPair.pas` and run it.
+4. Choose a save location for the JSON file when prompted.
+
+### JSON output format
+
+```json
+{
+  "GND|VCC": {
+    "total_capacitance_F": 2.2e-05,
+    "total_capacitance_str": "22uF",
+    "capacitors": [
+      {
+        "designator": "C1",
+        "value": "10uF",
+        "package": "0805",
+        "capacitance_F": 1e-05
+      },
+      {
+        "designator": "C2",
+        "value": "12uF",
+        "package": "0805",
+        "capacitance_F": 1.2e-05
+      }
+    ]
+  },
+  "GND|VDD": {
+    "total_capacitance_F": 1e-06,
+    "total_capacitance_str": "1uF",
+    "capacitors": [
+      {
+        "designator": "C10",
+        "value": "1uF",
+        "package": "0603",
+        "capacitance_F": 1e-06
+      }
+    ]
+  }
+}
+```
+
+### Protel PCB 2.8 ASCII — easier (Python, no Altium)
+
+**Yes — Protel PCB 2.8 ASCII is easier.** It’s plain text, so you can parse it with Python and no OLE/binary handling. You don’t need Altium running.
+
+1. **Export from Altium:** Open your PcbDoc → **File → Save As** (or **Export**) → choose **PCB 2.8 ASCII** or **Protel PCB ASCII** if your version offers it. Some versions use **File → Save Copy As** with format “PCB Binary/ASCII” or similar.
+2. **Run the Python script** on the exported `.pcb` / `.PcbDoc` (ASCII) file:
+
+   ```bash
+   python3 capacitors_by_net_pair.py board.PcbDoc
+   python3 capacitors_by_net_pair.py board.PcbDoc -o out.json
+   ```
+
+   **Input/output from .env:** Copy `.env.example` to `.env` and set `INPUT_FILE` and `OUTPUT_FILE`. The script reads these when the optional `python-dotenv` package is installed; CLI arguments override them. Without `.env`, you can still pass the input file and `-o` on the command line. By default the JSON is written to **`output/capacitors_by_net_pair.json`** (the `output/` directory is created if needed).
+
+See **`capacitors_by_net_pair.py`** for the script. It parses COMP/PATTERN/VALUE and NET/PIN data from the ASCII file and produces the same JSON shape as the DelphiScript.
+
+**Test file:** `tests/sample_protel_ascii.pcb` is a minimal Protel PCB 2.8 ASCII sample. Run:
+
+```bash
+python3 capacitors_by_net_pair.py tests/sample_protel_ascii.pcb -o tests/out.json
+```
+
+---
+
+## Compare component locations (two Protel files)
+
+**Script:** `compare_protel_locations.py`
+
+Loads two Protel PCB 2.8 ASCII files and reports **which components have moved** between them. Component position is the centroid of pin coordinates. Output is written to `output/compare_locations.json` by default.
+
+- **Moved:** designators with different (x, y) in file2, with old position, new position, and distance.
+- **Only in file1 / only in file2:** components that appear in just one file.
+
+**Usage:**
+
+```bash
+python3 compare_protel_locations.py board_v1.pcb board_v2.pcb
+python3 compare_protel_locations.py board_v1.pcb board_v2.pcb -o output/compare_locations.json
+```
+
+Use **.env** (optional): set `FILE1`, `FILE2`, and `COMPARE_OUTPUT`; CLI arguments override them. Use `--threshold N` to set the minimum position change to count as moved (default 1.0).
+
+**Test:** `tests/sample_protel_ascii.pcb` and `tests/sample_protel_ascii_rev2.pcb` (C1 and C2 moved in rev2):
+
+```bash
+python3 compare_protel_locations.py tests/sample_protel_ascii.pcb tests/sample_protel_ascii_rev2.pcb
+```
+
+### Notes
+
+- Only components with **exactly two pads** (each on a net) and **designator starting with `C`** are included (treated as capacitors). To include all two-pad parts, edit the script and remove the `And (UpperCase(Copy(Component.Name.Text, 1, 1)) = 'C')` condition.
+- Capacitance is parsed from the component **Value** parameter (e.g. `10uF`, `100nF`, `22pF`) and totalled in farads. Supported suffixes: F, mF, uF/µF, nF, pF.
+- Package is taken from the component’s **Pattern** (footprint) name.
+- If your Altium version uses different parameter or footprint property names, you may need to adjust the script (e.g. `DM_ComponentParameterName` / `DM_ComponentParameterValue`, or `Pattern` vs `Footprint`).