Building Alex Taradov’s open-source USB sniffer | Hacker News Reader

Building Alex Taradov’s open-source USB sniffer

downtowndougbrown.com

125 pointszdw18 comments

Taradov's sniffer is great - if you can get the parts, and can afford to wait for the PCB to ship, have a surface-mount oven, and so on - but alas he isn't selling them.

So I opted for a Cynthion instead, which also isn't shipping (yet) but promises to be available Real Soon Now™:

https://greatscottgadgets.com/cynthion/

.. similar device, a bit more feature-laden .. and supposed to ship at the end of the month. Grr...

You can solder QFN on a stovetop with a frying pan filled with play sand.

To quote a famous linguist: "Don't get technical with me!"

LCSC sells the CY7C68013A. You could order a board from JLCPCB with that part pre-soldered for a few bux

> but alas he isn't selling them.

Selling electronics is hard. You need a ton of upfront cash to order all the components, have to deal with a boatload of legal compliance stuff (if you're in Europe: RF interference, RoHS, registering and paying money for eventual recycling, CE certification tests, translated instruction manuals that have to accompany the product even though they are completely pointless), shipping, customs, refunds, repairs, your device bricking someone else's device, trademarks/licensing and associated fees (HDMI I'm looking at you), refunding people when your project fails for whatever reason but you already had to spend money (particularly the RF interference stuff has sunk many a project)...

In contrast, just putting out a board design and BoM is waaaaay easier. No way for anyone to hold you liable for anything.

Just curious, what about "PCBA" services i.e. those places that make the PCBs but also mount / solder components for you?

Is it generally possible to give them a BOM and ask to populate a whole board (i.e. order and receive a completed board, without having to solder everything)? Or are there necessarily going to be parts -- like the Cypress or Lattice chips here -- that the PCBA vendor will probably not have access to?

I'm just imagining a middle point between "here's a BOM" and "here's a finished product you can order" (with all of the regulatory issues that you're describing).

Could there be a "click here to have it created & soldered for you, but for this to still be a DIY thing" i.e. one click order-a-finished-board?

Spirit of the law vs letter of the law.

To order assembled boards from JLCPCB you just have to upload the PCB design files and BOM/placement files and give them a credit card. People are even recommending ordering the Cypress part from LCSC (JLCPCB’s parts division) already. So they might be able to completely assemble this with a straightforward enough order process. However, the minimum assembly order is two boards.

Edit: Another potential issue is that their in-stock parts do vary, so you wouldn’t be guaranteed of a successful order from an old BOM. The designer would probably need to update the files periodically.

Getting the boards physically manufactured is just the tip of the iceberg.

There is typically FCC testing that costs tens of thousands, emc/emissions testing, and then dafety testing (UL, etc.) If it's required.

It can cost hundreds of thousands to do all those things just to legally be allowed to sell your product in any real quantity.

As I understand it, development kits (such as this board) are exempt of certification. Nonetheless, the rest of your argument still stands.

I'm not too worried about certifications and all that stuff. For small batches sold on Tindie, it is not a huge deal.

But I don't want to stock the inventory and deal with shipping. Especially international shipping is annoying and expensive.

And there is not a lot of money to be made for small volumes.

If someone wants to build them and sell them - go for it. I just don't see this being profitable unless you have in-house pick and place machines.

Red Pitayas are similar and shipping now:

https://redpitaya.com/

> Where hardware sniffers come in handy is if you’re a firmware developer who is diagnosing a problem with a USB device or host you’re creating, or maybe you’re a driver developer working on a driver for a USB host controller. You need to see exactly what’s happening on the USB data wires to make sure that every packet looks correct. Perhaps you suspect your device’s firmware has a bug where the DATA0/1 toggle isn’t behaving as it should.

>The really cool thing about this sniffer is that it integrates with Wireshark. You can make use of protocol decoders already built into Wireshark for interpreting USB packets, as well as its fancy filtering capability. Ellisys devices, in comparison, use a proprietary USB analysis program. Protocol decoding is unlocked for an extra charge of thousands of dollars.

I bought all the components for this a couple weeks ago (based on the EEVBlog discussions), but haven't ordered the board yet. I wasn't able to find the 4x resistor networks in stock, so bought 2x networks instead and expect I can make those fit just fine.

Can t see the BOM, but isnt that dependent on the type of network?

https://github.com/ataradov/usb-sniffer

Anyway, I hate tiny SMD r-network as they are magnets for bridges. Would rather use discrete components if possible.

(Author here) I ended up buying a bunch of the components, including all of the passives, at LCSC. Notably the Cypress chip was much less expensive there too. Here's a link to the resistor network part I bought:

https://www.lcsc.com/product-detail/_UNI-ROYAL-Uniroyal-Elec...

On a side note, I mentioned in the video that it was super tedious to solder all of the passives. If I were doing this again I would strongly consider doing the JLCPCB/LCSC thing and having them populate all of the caps/resistors on the bottom side for me.

Meta: the actual main content is video, the article is mainly a meta piece about what an USB protocol analyzer is, and when you would want one. I did not watch the video (yet) but the article is pretty nice too as an introduction to the topic.

I do love when expensive/specialized things get cloned for cheap. It's nice that it happens so often in the hobbyist electronics world.

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