Project · draft
Soil-Moisture Drip Irrigation Controller (Milled MOSFET Board)
- intermediate
- 8-10 hours
Waters a kitchen garden or small plot only when the soil is actually dry, supporting steadier home food growing with less water.
Safety notes
- Water and electronics: mount the board and adapter above and away from the water tank in a closed case; run cables with a drip loop.
- Power only from a certified 5 V USB adapter. Do not build or modify a mains supply.
- Run the pump only when submerged, and add a maximum run-time limit in firmware so a failed sensor cannot empty the tank.
Draft and unofficial, not affiliated with Fab Academy or the United Nations. Check prices, GST and parts before you buy.
Summary
A XIAO ESP32-C3 reads soil moisture every few minutes; below your threshold it runs a small 5 V pump for a set number of seconds through drip tubing, then waits. A web page shows the moisture trend and lets you change thresholds.
What it teaches
Calibrate a capacitive soil sensor (dry air vs. wet soil), design and mill a low-side MOSFET switch with gate resistor, pull-down and flyback diode, add hysteresis so the pump does not chatter, and log moisture over Wi-Fi with deep sleep between readings.
Topics it touches, in Fab Academy-style terms:
- Electronics design
- Electronics production
- Input devices
- Output devices
- Embedded programming
- Networking and communications
Parts list
Parts cost
Some parts are not priced yet, so there's no total.
8 required parts are marked not priced yet below. Where a price is known it is shown per part, GST-inclusive as the seller listed it on 24 Oct 2026, with the GST rate unverified. Shipping is not included.
| Part | Qty | Unit | Price, GST-incl. as listed | Line cost | GST | Source |
|---|---|---|---|---|---|---|
| Seeed Studio XIAO ESP32C3 Wi-Fi & BLE Development Boardxiao-esp32c3 | 1 | pcs | ₹734 | ₹734 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Capacitive soil moisture sensor (v1.2/v2 style)soil-moisture-capacitiveSeal the exposed top edge (conformal coat or nail polish) | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| Mini submersible water pump, 3-5 V DCpump-mini-5v-submersible | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| Silicone / flexible tubing, ~6 mmsilicone-tube-6mmDrip line; pierce small holes or add drippers | 2 | m | not priced yet | not priced yet | GST unverified | no seller yet |
| N-channel MOSFET, SOT-23mosfet-nch-sot23Logic-level N-MOSFET, low-side pump switch | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| 1N5819 Schottky diode (flyback)diode-schottky-1n5819Flyback across the pump | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| 10 kOhm resistor, 1206 SMDres-10k-1206Gate pull-down | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| 100 ohm resistor, 1206 SMDres-100ohm-1206Gate resistor | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| 100uF / 25V Electrolytic Capacitor (Pack of 5)cap-100uf-25v-x5Bulk cap on 5 V; uses 1Pack: pack of 5 | 1 | set | ₹23 | ₹23 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| 15cm x 10cm Single Side Copper Clad Laminate PCB Boardpcb-copper-clad-15x10 | 1 | sheet | ₹39 | ₹39 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| 40x1 Female Berg Stripheader-female-40x1XIAO sockets | 1 | pcs | ₹12 | ₹12 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| USB wall adapter, 5 V 2 A (certified)usb-power-adapter-5v-2a | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| Type C USB Cable (1 metre)cable-usb-c-1mPowers the XIAO from the adapter | 1 | pcs | ₹65 | ₹65 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Part | Qty | Unit | Price, GST-incl. as listed | Line cost | GST | Source |
|---|---|---|---|---|---|---|
| Premium 1.75MM HS PLA 1 KG 3d Printer Filament - Cement grey Colourfilament-pla-1kgCase print; usually available from Fab Lab filament stock | 1 | pcs | ₹741 | ₹741 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Optional extras total, GST-inclusive as listed by the seller | ₹741 | |||||
The Part column links to the shared catalogue. Units are pcs, m, g, sheet or set, and a "set" is the seller's pack, as noted per part.
Tools you will need
- PCB mill with 1/64" end mill
- Soldering iron
- Multimeter
- KiCad
- Laptop with Arduino IDE or MicroPython
Build notes
Step-by-step build notes have not been written yet for this draft. The summary, the topics above and the parts list are what exists so far.
How to buy
There is no online checkout. To buy or import these parts, email info@curiosta.com and say what you need. The button opens your own email app with a draft; nothing is sent until you send it.
Prices on this site are third-party seller listings, not a Curiosta quote. Ask by email for availability, price and GST.