Turns Out That a Microcontroller Is All You Need to Host a File Server

As an enthusiast and collector of vintage tech, I’m always amazed by what engineers were able to achieve with primitive digital technology—and even mechanical or electromechanical systems. So, when our modern computers, with their powerful multicore CPUs and vast amounts of RAM, struggle and lag, I’m often left wondering how we manage to do so little with so much. The true reason for that is complicated and today’s software is far more resource-intensive than that of decades ago. But Zombieschannel didn’t let those excuses hold him back when he used a microcontroller to host a low-power file server.

If you had asked me how you should build something like a file server or NAS (network-attached storage) device, I would have told you to use a single-board computer, such as a Raspberry Pi or ZimaBlade. That’s what I did for my own NAS. But, as Zombieschannel proved, those aren’t actually necessary. A microcontroller can do the job — it might just not do the job quite as well.

A file server like this one only needs a couple of things: storage, network connectivity, and enough processing power and RAM to handle file transfers. An ESP32 microcontroller has the latter two all on its own. Zombieschannel got that in the form of an Arduino Nano ESP32 development board, then added an SD card reader module to provide storage. And while it isn’t a necessity, he also gave his device an OLED screen to display status information.

That hardware is quite simple, but programming the file server functionality wasn’t. Working with files using a microcontroller is always a bit of a struggle, as the minimal RAM doesn’t allow for the same kind of file handling that a computer can do. But with the help of ChatGPT, Zombieschannel was able to create an Arduino sketch that enables basic file storage and transfers.

This doesn’t have the features typical of a NAS, like automatic backups. And it struggles with large files — particularly because transfer speeds are slow. But it does the basics. The device connects to a Wi-Fi network and hosts a web interface accessible by local users. Those users can upload or download files through that interface. They can also use a simple command line interface to work with the file server over a USB serial connection.

Zombieschannel’s file server has a couple of advantages over one with a single-board computer. Most obviously, it is more affordable. But it also consumes much less power, which is a good thing for a device meant to run indefinitely.