Almost exactly four years ago, we came across a really neat module for sale on SeeedStudios. It was a $5 WiFi chip, able to connect your microcontroller project to the Internet with just a handful of wires and a few AT commands. This was the ESP8266, and it has since spawned an entire ecosystem of connected devices.

Now, there’s a new version of the ESP8266 that simply showed up on the Seeed website. Officially, it’s called the, ‘ESP8285 01M Wi-Fi SoC Module’, but you might as well start calling it ‘the Pluggable ESP module’. It’s the smallest ESP8266 module yet at 18mm square, and this one is designed to be plugged into a card-edge connector. It’s eighteen pins of wonder and 1MB of Flash, all ready to be stuffed into the next Internet of Things Thing.

The documentation for this module is sparse, and there isn’t even a mention of it on the AI Thinker website. That said, we can make some reasonable assumptions about what’s going on in this chip and what it can do. This module appears to be based on the ESP8285 SoC. Basically, it’s an ESP8266 with built-in 1MB SPI Flash. There are a handful of GPIOs available, and you should be able to build anything with this module that you could with other ESP8266 modules.

The highlight here is, of course, the card-edge connector. This is a module designed to be dropped into an existing product. You can program the module before hand, and assembly is a snap. The problem, though, is sourcing the relevant connector. It doesn’t look like Seeed has bothered to put a link to the right connector in the product description, although sourcing it shouldn’t be that much of a problem. The only question is if the card edge connectors on this module are hard gold (for multiple mating cycles) or just ENIG. Either way, if you’re plugging these modules into connectors dozens of times, you’re probably doing something wrong.