The Rise and Fall of the XBee Form Factor?

Alasdair Allan
2 min readFeb 20, 2018

I’ve spent a lot of time with the Digi XBee radios over the years, and they’ve formed the backbone of several of my bigger projects. At one point, the curiously shaped XBee form factor was more-or-less ubiquitous in the maker community with a number of third-party radios and shields imitating it, providing everything from Bluetooth to UART interfaces. There was even, at one point, a prototype dongle based around the Redpark Serial Cable for iOS that took an XBee. While the XBee modules themselves have even ended up in space.

However it’s been a while since I’ve seen a new XBee-shaped board released, so I was a little bit surprised to come across the SuperB on Crowd Supply.

The SuperB. (📷: Crowd Supply)

The SuperB is an open source, ESP32-based module for quickly and easily adding Wi-Fi and Bluetooth to your projects. It is XBee form factor compatible with 3.3V levels, UART, SPI, and GPIOs all broken out to appropriate headers. There is 4MB of flash onboard, with the possibility of an upgrade to 16MB, and the module is fully certified with integrated antenna and software stacks. For those of us with a lot of legacy XBee-compatible gear, it’s actually sort of an interesting proposition. Although no pricing or ship date has been announced if you’re interested, it’s coming soon to Crowd Supply.

What makes the SuperB’s arrival somewhat more poignant is that its arrival marks the demise of the form factor, as Digi recently announced the next generation of XBee modules which look nothing like the traditional quirky XBee. The new XBee form factor is the now ubiquitous castellated module.

Often destined to be mounted on other circuit boards, the castellated module is now the default way to get today’s tiny surface-mount parts into the hands of a wider community that often doesn’t have the tools, or the skills, to make use of them directly.

This became especially obvious with the arrival of the ESP8266, which led to an ESP-12-like form factor becoming a default. While competitors like the RTL8710 now come in very similar configurations, with some even being pin compatible. So for those used to the ESP range of modules, the new XBee 3 form factor looks awfully familiar.