RFIDler – An Open Source Software Defined RFID Reader/Writer/Emulator (2013)
adamsblog.aperturelabs.com
adamsblog.aperturelabs.com
In the HF space, the proxmark performs well - the HydraNFC is a very powerful device alternative, allowing real time sniffing - but is more hands on than the proxmark. The Chameleon Mini is also a great complementary device for easy emulation of HF tags.
Just a head's up - the proxmark clones, and specifically the proxmark easy clones are notoriously poor clones of a system that is already quite temperamental.
If you're in the market, check out https://proxmark.com for licensed distributors of current stock.
To date, the latest version is the Proxmark 3 RDV4, which is incredibly compact. If you combine the Proxmark with Walrus.app, you have a very capable and portable LF sniffing system.
Adam's system (the device in the article) is a great system, and he's a very smart and affable person if you have the chance to meet him.
Full disclosure: I am associated with https://lab401.com, an official distributor of the Proxmark 3.
Also, seems you can't buy them and the kickstarter ended[0] back in Sep 2013. Last update on the firmware was Jan 2018[1].
Seems pretty cool and I'd want one but seems to have died, now. :(
[0] - https://www.kickstarter.com/projects/1708444109/rfidler-a-so...
edit: Aliexpress is even cheaper ($42) and is not in bulk (also, the hardware Proxmark design is open source): https://www.aliexpress.com/item/Newest-version-proxmark3-dev...
I've just tried to find a page with the reasons about why they're no longer supporting it, but I've failed to find it.
I seem to remember it's something to do with wanting to support the more fancy versions that cos 5-10x more :/
However I can't find the page, so maybe I'm not remembering something correctly.