We found all the parts needed to build a simple U2F security token thanks to Github. Here’s the link: https://github.com/conorpp/u2f-zero/wiki/Parts-List
Basically there are 8 components per token. All should be surface mount parts. Here’s what you need:
| PART | MANUFACTURER PART NUMBER | PRICE PER | WHERE TO FIND |
| Microcontroller | EFM8UB11F16G-C-QSOP24 | $1.38 | https://www.digikey.com/ |
| Secure Element (Authentication chip) | ATECC508A-SSHDA-B | $0.75 | https://www.digikey.com/ |
| RGB LED | CLVBA-FKA-CAEDH8BBB7A363 | $0.42 | https://www.digikey.com/ |
| 100Ω Resistor | CRCW0805100RFKEA | $0.10 | https://www.digikey.com/ |
| Zener Diode | DF5A5.6FUTE85LF | $0.46 | https://www.digikey.com/ |
| Push Button | TL3305AF260QG | $0.19 | https://www.digikey.com/ |
| 4.7µF Bypass Capacitor | JWK212C6475KD-T | $0.47 | https://www.digikey.com/ |
| 0.1µF Bypass Capacitor | GRM219R71C104MA01J | $0.12 | https://www.digikey.com/ |
| Printed Circuit Board (PCB) | UPLOAD YOUR OWN GERBER FILES OR USE THE ONES LISTED IN THE ABOVE GITHUB LINK. MUST SELECT THE 2MM OPTION. | $40.00 FOR A +/-10 PROTO-PACK (2MM OPTION IS MORE EXPENSIVE). | http://dirtypcbs.com/store/pcbs |
NOTE: If you can’t find a component, or it isn’t in stock on Digikey, check https://www.mouser.ca/
In addition to this, there are some other things you can buy to make your building experience easier.
- A programmer- https://www.digikey.ca/product-detail/en/silicon-labs/SLSTK2000A/336-3156-ND/5115713 (this is the one we ended up choosing). Price: $41.79
- Lead Free, No-Clean Solder Paste- https://www.digikey.ca/product-detail/en/chip-quik-inc/SMD291SNL50T3/SMD291SNL50T3-ND/5130160 (for when we use a reflow oven to construct our tokens). Price: $23.62
- Desolder Braid (for just in case and practicing)- https://www.digikey.ca/product-detail/en/mg-chemicals/444/473-1067-ND/949515 This stuff is THE best. Price $21.84
- PCB Stencil- can order this while ordering your PCB. We just stuck with a normal steel stencil.
- Toaster Oven- I’ll get into this in greater detail later (look out for a reflow oven post), but basically the toaster oven acts as a way to more easily and reliably solder your surface mount components to the board. We got ours for $5 used.
ANOTHER NOTE: Digikey is awesome. We ordered all these things (and extras of each) one afternoon, and they had already arrived by 9 am the next morning.
Here are pics of all the goodies we got! (kind of like an unboxing slideshow)
