Someone already wrote a program and made a simple instruction for building the hardware that lets you read every type except for the "Avid Encrypted" tags, which can be read but not decrypted. They also put a web API online for decrypting the Avid Encrypted tags and they have instructions for how to build your own decryptor (they call it a "translator"), however building the decryptor requires a ~$300 piece of hardware. Everything is here.
Standards and "Standards"
All chips operate at either 125 kHz (ISO) or 134.2 kHz (proprietary) but a scanner using either frequency can read both types:
Although ISO chips are optimized for 134.2 kHz, in practice they are readable at 125 kHz and the "125 kHz" chips are readable at 134.2 kHz.
-- from this section on wikipedia
ISO 11784 & 11785
Includes half-duplex (HDX) and full-duplex (FDX) types. I've seen references to FDX-A and FDX-B but unsure of the difference.
Readers retail for ~$150 on ebay.
Also known as Trovan Unique. Also used by some HomeAgain chips and Bayer chips.
FECAVA / Destron
- Avid EuroChip
- Original HomeAgain chip
Also known as Avid Encrypted.