2 layers26.4 × 36.4 mm
PCB-02
Gerafftes/Observatory
Experimental 1TX/4RX WiFi CSI system researching camera-free presence, movement, room position, heart rate, and breathing rate.
6 parts2
2 layers26.4 × 36.4 mm
PCB-01
Gerafftes/Observatory2Experimental 1TX/4RX WiFi CSI system researching camera-free presence, movement, room position, heart rate, and breathing rate.
- Size
- 26.4 × 36.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 6
- Nets
- 20
- Pads
- 30
- Tracks, vias
- 22, 2
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 4 Jul 2026
- Updated
- 7 Nov 2026
Overview
PCB-01 is an open-source printed circuit board by Gerafftes, from the Gerafftes/Observatory repository on GitHub. It is a 2-layer board of 26.4 × 36.4 mm with 6 parts on 20 nets, routed with 22 tracks and 2 vias.
It is built around the HLK-LD2450. Its parts include 2 capacitors and 2 ICs. It belongs with the radio and wireless boards and the ESP32 and RISC-V boards of this library.
Main components
1README
hardware/mmwave-PCB/PCB-02/README.mdPCB-02 – ESP32-C3 SuperMini / LD2450 carrier
This is a revised, separate copy of PCB-01. The original project was not modified.
Changes from PCB-01
- Replaced the hidden castellated contact pads with two 2.54 mm through-hole rows for pin headers or sockets.
- Added a left-side USB-C opening and a right-side board cutout below the ESP antenna.
- Kept the PCB-01 outer envelope (26.45 x 36.42 mm) and both 2.20 mm mounting-hole positions unchanged for case compatibility.
- Placed the
PCB-02and@gerafftesidentification together along the top edge on F.Silkscreen. - Kept copper and UART routing out of the antenna cutout.
- Kept C1 and C2 as hand-solderable SMD parts and moved them close to the LD2450 connector.
- Widened the 5 V and GND routing after the ESP header transition.
- Routed every copper corner with a 45-degree transition; there are no 90-degree track bends.
- Preserved the required UART mapping:
- LD2450 TX -> ESP GPIO20 / RX
- ESP GPIO21 / TX -> LD2450 RX
Assembly
| Reference | Part | Important detail |
|---|---|---|
| U1 | ESP32-C3 SuperMini HW-466AB | 2 x 8 pins, 2.54 mm pitch, 15.24 mm row spacing; 1.70 mm pads with 1.00 mm drills for headers or sockets |
| U2 | HLK-LD2450 connector | 2 x 4 pins, 2.00 mm pitch |
| C1 | 100 nF ceramic capacitor | SMD 0805, non-polarized, hand-solder footprint |
| C2 | 10 uF bulk capacitor | SMD 1206, non-polarized, hand-solder footprint |
The right side marked ANT KEEP CLEAR must remain free. Do not add copper, wires, metal spacers, or an enclosure wall directly below or in front of the ESP antenna.
Before ordering, compare the physical ESP module against these verified footprint assumptions: 18.00 x 22.52 mm body, 2.54 mm pin pitch, 15.24 mm row spacing, USB end beside 5V/GND, and antenna end beside GPIO20/GPIO21. Third-party SuperMini clones can differ.
The mounting holes match PCB-01 at (163.50, 89.00) mm and (172.00, 89.00) mm. PCB-02 has the same outer width and height as PCB-01, but the case still needs openings around the new USB and antenna cutouts.
Validation
- KiCad ERC: 0 violations.
- KiCad DRC including schematic parity: 0 violations, 0 unconnected items, 0 footprint errors.
- Copper angle audit: all segments are horizontal, vertical, or 45 degrees; no 90-degree track bends.
- Final Gerber and drill outputs are in
gerber/.
These checks validate the PCB files and connectivity. They do not prove that the existing ESP or LD2450 hardware is functional.
Parts
6| Qty | Value | Footprint | References |
|---|---|---|---|
| 1 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1 |
| 1 | 10uF | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C2 |
| 1 | ESP32-C3 Super Mini | Project_Footprints:ESP32-C3_SuperMini_HW-466AB_Checked | U1 |
| 1 | HLK-LD2450 | Connector_PinHeader_2.00mm:PinHeader_2x04_P2.00mm_Vertical | U2 |
The 4 most common of 6 parts.
Questions
How big is the PCB-01 PCB?
It measures 26.4 × 36.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the PCB-01 use?
6 parts, built around the HLK-LD2450. 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 PCB-01 KiCad files?
From the Gerafftes/Observatory repository on GitHub, at the commit this page was made from: the board is hardware/pcb-01/PCB-01.kicad_pcb and its schematic hardware/mmwave-PCB/PCB-02/PCB-02.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PCB-01 design in my own project?
Its repository states no licence, so its author keeps all rights: ask Gerafftes before reusing the design.
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