2 layers37 × 19 mm
Passive rpi hub75-adapter
hzeller/rpi-rgb-led-matrix
Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO
2 parts4.4kGPL-2.0
2 layers15 × 3.1 mm
F91 nfc
MacroLens/NFC_F91W6This is a mod for the Casio F91-W to include a 125kHz NFC chip, specifically the T5577. The goal of this was to create a working tag that would fit in the watch with no modification to the outer case and water resistance.
- Size
- 15 × 3.1 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 2
- Nets
- 2
- Pads
- 4
- Tracks, vias
- 8, 2
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 30 Jul 2021
- Updated
- 30 Jul 2021
Overview
F91 nfc is an open-source printed circuit board by MacroLens, from the MacroLens/NFC_F91W repository on GitHub, published under the MIT licence. It is a 2-layer board of 15 × 3.1 mm with 2 parts on 2 nets, routed with 8 tracks and 2 vias.
It belongs with the radio and wireless boards of this library.
README
README.mdNFC_F91W
This is a mod for the Casio F91-W to include a 125kHz NFC chip, specifically the rewritable ATA5577. The goal of this was to create a working tag that would fit in the watch with no modification to the outer case and water resistance.
Specifications:
- 125kHz Frequency NFC using the ATA5577
- PCB Dimensions:
- 15mm width
- 3.1mm length
- 0.3mm height
- Assembled Height: ~3.5mm
- Read range: ~25mm (Rough Estimate)
BOM:
Build Details:
In order to make an antenna for this frequency the major issue I faced was that a planar antenna in a PCB would not fit in the casing for the required inductance of 4.9125 millihenrys. To rememdy this a 4308RV transponder coil was used. The PCB was designed to fit in the watch module above the LCD display on the two upper pegs that hold the LCD PCB in. In order to make space for the antenna a rectangular hole must be filed into the module housing. This mod will not be visible on the outside and the antenna sits flush with the housing so there should be no issues with the reading angle of the watch face changing.
The PCB was designed in KiCad and calculations for the required inductance were made using the following reference (This can be generalized to other frequencies).
The PCB is difficult to manufacture and solder. Soldering these will require a stencil and hot air station for the small traces of the ATA5577. My success rate, soldering with a hot air station and stencil, is 75% having only soldered four tags.
Parts
2| Qty | Value | Footprint | References |
|---|---|---|---|
| 1 | 4308RV | nfc_chip_footprints:4308RV | U1 |
| 1 | ATA5577CM2xxxC-DBQ | nfc_chip_footprints:ATA5577CM2xxxC-DBQ | M1 |
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Questions
How big is the F91 nfc PCB?
It measures 15 × 3.1 mm and has 2 copper layers, 1.6 mm thick.
What parts does the F91 nfc use?
2 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the F91 nfc KiCad files?
From the MacroLens/NFC_F91W repository on GitHub, at the commit this page was made from: the board is kicad_project_files/f91_nfc.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the F91 nfc design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).