Embedded software program engineer Doug Brown has constructed an open supply USB 2.0 sniffer, based mostly on a design launched earlier this 12 months by Alex Taradov — proving that the design will be replicated, whereas additionally documenting the errors he made alongside the way in which as a lesson for anybody trying to construct considered one of their very own.
“Usually, USB sniffers like this could price hundreds of {dollars}, particularly when you’re paying for fancy protocol decoding and in addition need high-speed 480Mbps assist,” Brown explains in a publish dropped at our consideration by Adafruit. “This one prices about $50 in elements to assemble your self, though it would take hours to solder and you will have some expertise with scorching air (or reflow oven) soldering for the reason that USB PHY is a QFN chip with an uncovered pad beneath.”
The gadget in query is a design launched by Alex Taradov two months in the past, designed to take a seat between a USB 2.0-compatible gadget and a bunch PC and monitor the visitors between the 2 — both utilizing a devoted command-line package deal or a plugin for Wireshark. It is a useful device for debugging or reverse-engineering USB gadgets, and as Brown factors out it is quite a bit cheaper than business options — however provided that it is truly doable to construct one from the information Taradov launched.
Armed with the Gerbers and a invoice of supplies, Brown set about doing precisely that — documenting the method in an in depth video, full with the “studying alternatives” he encountered on the way in which — together with having to solder a quad flat no-lead (QFN) package deal, alongside drag-soldering the legs of the Cypress CY7C68013A microcontroller and Lattice LCMXO2 FPGA which drive the gadget.
A few of these challenges have been self-inflicted — “ideally you’d use solder paste [here],” Brown explains whereas soldering the QFN package deal, “however I am not going to try this, what I will do is put solder on all of the pads, particularly that middle pad, as a result of that is floor so you actually need that solder” — whereas others are merely the challenges related to compact surface-mount gadgets.
Brown’s construct is predicated on Alex Taradov’s authentic design, pictured. (📷: Alex Taradov)
Whereas a number of the soldering wanted a bit of touch-up post-assembly, Brown’s model of Taradov’s USB sniffer does certainly work — and even matches within the 3D-printed case Taradov launched for it, proving that the challenge is replicable for anybody in search of a budget-friendly USB sniffer.
Extra info on the challenge is accessible on Brown’s web site, whereas the USB sniffer Gerbers, invoice of supplies, and supply code can be found on Taradov’s GitHub repository underneath the permissive BSD three-clause license.
