---

One of the benefits of open source microcontrollers and other hardware is that with a modest investment in a software package such as EagleCAD, it’s a simple matter to create custom boards to fit the size and weight requirements of your robot. For example, let’s say you’re working on a pint-sized quadcopter drone and every bit of extra circuit board not only cuts down on battery time, but requires a larger enclosure. If you’re working with, say, an Arduino Uno, then you can leave off the USB connector and create a round instead of rectangular board to better fit your quad design.

Custom has a cost, however. The first is, well, cost — in dollars and cents. You can probably pick up a standard Arduino Uno for less than $30, including shipping. A custom Arduino — in comparison — can easily run $30 for shipping alone because of the multiple vendors involved in supplying parts. There is the board manufacturing cost, as well as the cost of the components to populate the board. There’s also the cost in the time and effort required to design the board, order the components, wait a week or two for everything to arrive, and then spend a day assembling and testing the board.

Perhaps the greatest cost in going custom is the cost of keeping up. It seems as though the microcontroller companies are announcing new boards on a quarterly basis. They’re faster, more powerful, and sometimes even cheaper. Fortunately, they tend to keep the same physical footprint and connectors. So, upgrading your robot to the latest board is a 10 minute board swap. Not so with a custom board — especially if every component is soldered directly to it.

Given this reality, why would anyone opt for a custom microcontroller board? Well, the size and weight optimization noted earlier can be of significant value. If you’re building a long, thin rocket, then the only option for an onboard controller may be a long, thin microcontroller board. Another factor is volume. Let’s say you belong to a rocket club with 100 members, each of whom wants a microcontroller of their own. When you get into the 100+ board orders, there is a significant drop in per board cost.

Moreover, there’s the fun factor. Sure, it may be economically impractical to create a custom board instead of using an off-the-shelf version. The same could be said for just about any electronics kit or DIY project for that matter. It’s hard to beat the price of electronics built in China, but there is a sense of accomplishment and simple fun when you design your own board in software, send the file off to be manufactured, and then populate the board yourself.

And that, you can’t buy.  SV