Your BOM is not your COGS

“The prototype was $12 in parts, so I’ll sell it for $15.” That is your recipe for disaster, and why so many Kickstarter projects fail. The Bill of Materials (BOM) is just a subset of the Cost of Goods Sold (COGS), and if you aren’t selling your product for more than your COGS, you will lose money and go out of business.

We’ve all been there; we throw together a project using parts we have laying around, and in our writeup we list the major components and their price. We ignore all the little bits of wire and screws and hot glue and time, and we aren’t shipping it, so there’s no packaging to consider. Someone asks how much it cost, and you throw out a ballpark number. They say “hey, that’s pretty reasonable” and now you’re imagining making it in volume and selling it for slightly higher than your BOM. Stop right there. Here’s how pricing really works, and how to avoid sinking time into an untenable business.

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KiCAD BOM Management

KiCAD remains a popular tool for designing PCBs and other circuits, and with good reason: it’s versatile and it’s got pretty much everything needed to build any type of circuit board you’d want. It also comes with a pretty steep learning curve, though, and [Jeff] was especially frustrated with the bill of materials (BOM) features in KiCAD. After applying some Python and Kivy, [Jeff] now has a BOM manager that makes up for some of KiCAD’s shortcomings.

Currently, the tool handles schematic import, like-component consolidation, and a user-managed parts database that can be used to store and retrieve commonly used parts for the future. All of the changes can be saved back to the original schematic. [Jeff] hopes that his tool will save some time for anyone who makes more than one PCB a year and has to deal with the lack of BOM features native to KiCAD.

[Jeff] still has some features he’d like to add such as unit tests, a user guide, and a cleaner user interface. What other features are you anxious to see added to KiCAD?

This script is a great tool for anyone who has had similar frustrations. KiCAD is popular to modify and expand, too: there have been tools for mechanical CAD export, a parts-generator and cost-tracker, and an Eagle to KiCAD converter if you’re thinking of making the switch.