Plant water array

Plant Water Array — PCB Design

Breakout board for ESP32 DevKit V1 with OLED display and 5 moisture sensor connectors.

Board Summary

+--------------------------------------------------+
|                                                  |
|  [OLED 4-pin]              [ESP32 DevKit V1]    |
|   GND VCC SCL SDA           L-socket  R-socket  |
|                              (1x15)    (1x15)    |
|                                                  |
|  [J_S1] [J_S2] [J_S3] [J_S4] [J_S5]           |
|   G34    G35    G36    G39    G32               |
+--------------------------------------------------+

Parts List (per board)

PCB Connectors (solder onto the board)

Sensor Cable Parts (per sensor, 5 per board)

Quantities for 5 Boards

Where to Buy

• Amazon (fastest) — search "JST XH connector kit" ($10-15 for assorted kit with headers + housings + crimp pins). Separately get a pack of "female pin header socket 2.54mm" ($5-7).
• AliExpress (cheapest, 2-3 week shipping) — same searches, about 1/3 the price.
• Digikey / Mouser (exact part numbers, reliable) — B3B-XH-A ~$0.15ea, XHP-3 ~$0.10ea, SXH-001T-P0.6 ~$0.05ea, pin sockets ~$0.50ea.

A JST crimp tool (~$25) is helpful but you can solder wires directly to the crimp contacts instead.

Pin Mapping

Generating the Netlist

cd pcb/
python generate_netlist.py
# Produces plant_water_array.net
# Open KiCad PCB Editor → File → Import Netlist

No dependencies required — just Python.

PCB Layout Tips

• ESP32 socket headers in the center (25.4mm apart, verify with your DevKit)
• OLED header on top edge
• JST-XH connectors along bottom or side edge
• Keep traces wide (0.5mm+)
• Pour a ground plane on the back copper layer (select B.Cu → Place → Add Filled Zone → net GND)

Ordering PCBs (JLCPCB)

1. Export Gerbers from KiCad: File → Fabrication Outputs → Gerbers, then Generate Drill Files
2. Zip the gerber_out/ folder
3. Go to jlcpcb.com → Order Now → upload the zip

JLCPCB Settings

Cost: ~$2-5 + shipping ($1-5 standard, ~$15-20 DHL express).

Sensor Cable Assembly

Each sensor cable is a 3-wire bundle with a JST-XH plug on the board end:

Sensor                Board End
┌─────────┐         ┌──────────┐
│ S (sig) │─────────│ Pin 3    │
│ + (VCC) │─────────│ Pin 2    │
│ - (GND) │─────────│ Pin 1    │
└─────────┘         └──────────┘
                    JST-XH plug

Use 3-conductor cable (ribbon cable or twisted triple) — can run 1-2 meters without issues for analog signals.