build your own.

everything you need to build a cairn is published. BOMs, assembly guides, 3D print files, firmware. all open. buy the parts. build the thing. add the software when you're ready.

browse parts lists download STL files
cairn maker workspace — soldering station, Raspberry Pi, and components
cairn in field use — solar panel charging device on wooden table

we publish every design because self-reliance means you don't need our permission.

parts lists.

every component, every module. source them yourself.

cairn core
the brain. compute, storage, and AI inference in a single board.
component qty est. cost
Raspberry Pi 5 8GB 1 $175 buy
WD SN770 1TB NVMe 1 $80 buy
Pimoroni NVMe Base 1 $20 buy
Pi 5 Active Cooler 1 $14 buy
Samsung EVO 256GB microSD 1 $14 buy
USB-C cable 1 $5 buy
estimated total ~$308
cairn arc
solar power. LiFePO4 battery + foldable panel. off-grid energy independence.
component qty est. cost
Jackery Explorer 100 Plus (100Wh LiFePO4) 1 $109 buy
BigBlue 30W Foldable Solar 1 $70 buy
USB-C PD cable (1m) 1 $8 buy
12V car to USB-C adapter 1 $8 buy
estimated total ~$195
cairn signal
standalone mesh comms terminal, SDR receiver, and extended WiFi range. works without the Pi powered on.
component qty est. cost
LILYGO T-Display P4 + MeshOS (mesh terminal) 1 ~$70 buy
RTL-SDR v4 1 $40 buy
Alfa AWUS036ACH WiFi adapter 1 $50 buy
Telescoping SMA antenna 1 $10 buy
estimated total ~$140
cairn web
sensor network. 8 solar-powered ESP32 perimeter nodes with PIR, magnetic, and environmental sensing.
component qty est. cost
ESP32-C3 SuperMini 8 $2.50 ea ($20) buy
HC-SR501 PIR sensors 8 $1.25 ea ($10) buy
Magnetic reed switches 6 $1.50 ea ($9) buy
1000mAh LiPo batteries 8 $3 ea ($24) buy
5V 1W mini solar cells 8 $2 ea ($16) buy
estimated total ~$79
cairn forge
repair and IT toolkit. soldering, diagnostics, every adapter and cable you need in the field.
component qty est. cost
Pinecil V2 soldering iron 1 $26 buy
Aneng AN8008 multimeter 1 $30 buy
iFixit Mako 64-bit driver kit 1 $40 buy
USB-C hub (7-in-1) 1 $25 buy
FTDI USB-Serial adapter 1 $18 buy
SATA-USB adapter 1 $15 buy
Ethernet cable (15m) 1 $8 buy
USB adapter set 1 $3 buy
estimated total ~$165
cairn view 7
display. 7-inch IPS touchscreen for direct interaction with cairn core.
component qty est. cost
7" IPS LCD touchscreen (HDMI) 1 $60 buy
HDMI cable (0.3m) 1 $5 buy
Micro-HDMI adapter 1 $5 buy
Bluetooth keyboard (compact) 1 $5 optional
estimated total ~$75
note: prices are estimates based on common retail sources as of early 2026. actual costs vary by region and availability. affiliate links help support cairn development at no extra cost to you.
all six modules
~$962

build only what you need. cairn core + arc gets you a working system for ~$503. add modules as your situation requires.

then add the software.

you've built the hardware. now add the brain.

cairnOS $79

the full operating system. AI + 120GB content. flash to your NVMe.

cairn archive $39

just the content library. 120GB of curated survival knowledge.

explore software

open source files.

3D

STL files

all module enclosures. PETG recommended for durability. includes snap-fit lids and ventilation channels.

download
CAD

STEP files

for aluminum CNC machining. full parametric models for professional fabrication.

download
EE

wiring diagrams

every module, every connection. color-coded pinouts and cable routing guides.

download
PCB

schematics (KiCad)

full electronics schematics. open in KiCad 8+. includes BOM exports.

download
FW

firmware (GitHub)

ESP32 sensor firmware for cairn web. PlatformIO project. MIT license.

view on github
DOC

assembly guides

step-by-step photo walkthroughs for every module. assumes no prior experience.

browse guides