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How to Make a Parts List (BOM) in Protoboard Designer

Estimated reading time: 6 minutes

A parts list (also called a BOM, bill of materials) tells you what to buy for your board: how many 10 k resistors, which capacitors, which chips. Protoboard Designer can build it from your board and save it as a CSV file that shops like LCSC and Mouser can read.

Parts lists are optional. Nothing on your board gets a number until you ask for it.

Step 1: Number your parts​

Every part on a board has a designator: a letter and a number, like R1, C3 or U2. The letter says what kind of part it is (R for resistor, C for capacitor, D for diode or LED, U for chip, J for connector). The number tells the parts of the same kind apart.

  1. Open Insert and, under Generate, tap Add designators.
  2. Leave Only parts without a number selected. Parts that already have a number keep it. Choose Renumber everything only if you want to start again from 1.
  3. Choose the Order: Rows numbers left to right, then the next row down. Columns numbers top to bottom, then the next column.
  4. Tap Apply.

When it is done you get a short summary, like R1–R6, C1–C5, D1–D2. The whole run is one step, so Undo takes it all back.

The prefix U

If the app cannot tell what kind of part something is, it calls it U and tells you how many parts got that. Select those parts and type the right letter in the Prefix field in the Part section.

Parts you copy with Duplicate keep their letter but lose their number (R?), so you never get two R3. Run Add designators again to number the copies.

Things that are not parts​

Fiducials, mounting holes and solder jumpers from the library are left out. The groups Protoboard Designer generates for you (mounting holes, coils, PCB antennas, via stitching, QR and bar codes) are marked Not a part when they are made, so they are never numbered or listed. Anything else you do not want to buy, like a perfboard area or a logo made of pads, you can mark with Not a part in the Part section. It is left out of the numbering and of the list.

Step 2: Check and edit a part​

Select a part and open the Part section in the side panel. (On a board with no designators the section is folded; open it.)

  • Designator: type your own, like J_PWR. A name that does not end in a number is yours and is never renumbered. You are warned if another part already has the same designator.
  • Value: 10k, 100nF, 1N4148. The list needs it for resistors, capacitors and inductors. A library part named like 1N4148W (SOD-123) already has a value from its name (1N4148W); most others need one typed in.
  • Not a part: leaves it out of the numbering and the list.
  • Label: moves the printed designator above, below, left or right of the part.

If you select several parts, Value, Not a part and Prefix apply to all of them.

Step 3: Print designators on the silkscreen​

Designators are only on the screen until you print them.

  1. Open Add designators again.
  2. Turn on Print on silkscreen. Each numbered part gets a small label beside it on the silkscreen layer.
  3. Tap Apply.

The labels belong to their parts: they move, rotate and flip with them. If a label ends up in a poor spot, turn on Re-place labels and apply, or use Label in the Part section. Remove designator labels takes all the printed labels off but keeps the numbers.

The text is about 1.2 mm high with a 0.165 mm line, above the 1 mm text and 0.15 mm line a fab like JLCPCB prints clearly.

Step 4: Show designators on screen​

If you only want to see the numbers while you work, without printing them, turn on Show designators in the editor's view settings. It draws each designator over its part. It is only for you: it is never printed, never in an export, and not in the Photoview.

Step 5: Export the parts list​

  1. Open Export and choose Parts list.

  2. Read Before you order. These checks never stop you from exporting, but they point at problems:

    • parts with no designator or no number (there is a button that runs Add designators);
    • the same designator used twice;
    • resistors, capacitors or inductors with no value;
    • designated parts that sit inside another listed part (the outer part is the one bought, so they are not listed);
    • how many groups you marked Not a part.

    Tap a part in a check to jump to it on the board.

  3. Choose your options:

    • Layout: One line per value and package gives one line per kind of part (10k, R_0805, 6 pieces, R1, R3, ...), which is what a shop wants. One line per part is for checking.
    • Boards to build: if you order for 5 boards, the file shows the amount per board and in total.
    • Include: all parts, only surface-mount (SMD) parts, or only through-hole (THT) parts. Use this when you buy SMD parts from LCSC and through-hole parts at a local shop. A part that has both kinds of pins is on both lists, so it is never forgotten.
    • Separator: comma, or semicolon. If Excel opens the file in one column (common in Hungarian, German and other decimal-comma languages), export with the semicolon.

  4. Look over the preview, then tap Export.

The file is called <your project>_parts.csv. The headers are always in English (Designator, Value, Package...) because that is what the shops' upload pages look for.

A value that starts with + or -

To keep spreadsheets from running a value like =1+1 as a formula, Protoboard puts an apostrophe in front of values that start with =, +, - or @. Excel shows that apostrophe, so +5V appears as '+5V. Remove it in the spreadsheet if you care.

Step 6: Upload it to LCSC or Mouser​

LCSC (and JLCPCB assembly): in the BOM tool, choose to upload a file and pick your CSV. The columns Designator, Qty/Quantity and Value are usually matched automatically, but you may be asked to map them. You then choose the exact LCSC part for each line.

Mouser: open BOM Tool or Upload a BOM, pick the CSV, and you may be asked to map the columns: Qty to quantity, Value to description or customer part number. Mouser then suggests parts for each line.

Either way, a list built from values like 10k still needs you to pick the exact part number. Check the footprint size (the Package column) before ordering: R_0805 and R_0603 are not interchangeable.

Good to know​

  • Older versions of the app show the printed designators as ordinary text on the silkscreen. Versions from the safety release on keep your numbers when they open and save the board; earlier ones may drop them.
  • Part numbers (manufacturer, MPN, LCSC number) are not stored on parts yet; for now you pick them in the shop.
  • A part with a designator but no number is listed too (as R?) and flagged by the checks.