Software USB On the ESP8266

A while back, [cnlohr] needed a USB keyboard and mouse. His box ‘o junk didn’t hold this particular treasure, and instead of hopping on Amazon like a normal geek or venturing into the outside realm on a mid-level ‘store’ quest like a normal person, [cnlohr] decided to turn an ESP8266 into a USB keyboard and mouse. How hard could it be? The ESP doesn’t support USB, but bitbanging hasn’t stopped him before. The end result is a USB stack running on the ESP8266 WiFI module.

[cnlohr] has been working for about a month on this USB implementation for the ESP, beginning with a logic analyzer, Wireshark, Xtensa assembly, and a lot of iteration. The end result of this hardware hacking is a board based on the ESP8285 – an 8286 with integrated Flash – that fits snugly inside a USB socket.

This tiny board emulates low-speed USB (1.5 Mbps), and isn’t really fast enough for storage, serial, or any of the fancier things USB does, but it is good enough for a keyboard and mouse. Right now, [cnlohr]’s ESP USB device is hosting a webpage, and by loading this webpage on his phone, he has a virtual keyboard and mouse on a handheld touchscreen.

If you’re keeping track, [cnlohr] has now brought Ethernet and USB to a tiny microcontroller that can be bought for a few bucks through the usual online outlets. If you’d like to build your own ESP USB stick, all the files are over on the Gits.

Thanks [lageos] for the tip.

37 thoughts on “Software USB On the ESP8266

  1. That seems like an exercise in sadism, with turn key solutions at <3$ not even looking for it.

    There is always that trade off between selling a month of your life for 3 $ or not when making things.

    Sometimes its hard not to invoke "because i can" even thought maybe you shouldnt.

    Hattip anyways it would have taken me 2 months im sure.

          1. Whoops, accidentally reported child comment. Sorry, Addidis :(. What I was going to reply with was: “$3 more, per project, times all the projects that will ever use espusb, which is like 10, so $30.”

    1. If he takes the time to fill out the usb spec to a functional level agreed. Its liable to play havoc on devices its used on if they send it a command its not prepared to handle as it stands with a quasi sw usb stack.

  2. Wonder if it would be possible to bit-bang USB host as well, thus turning the ESP into a mouse and keyboard “logger”, except instead of logging you’re broadcasting blind across a network silent SSID. Could control it remotely as well.

  3. I am beginning to realise I have a terrible curse, that prevents me from authoring 1337 hax… I seem to have this unfortunate ability to find what I want…. I go, “I need to write a …. oh there’s an app” … “I need a thing that… oh, this will work.”

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