Soil Moisture Driven Irrigation Controller
An irrigation controller that waters based on measured soil moisture and forecast rainfall rather than a timer, with a documented measurement of water saved. The engineering that matters is what happens when the network, the sensor or the power fails.
Intermediate
A small team, or one strong student willing to learn something new.1 semester, 2 students
5 to ship
3 optional extrasSuggested stack
What you should ship
- Sensor node measuring soil moisture at two depths plus temperature, battery powered with measured runtime
- Irrigation decision logic using moisture thresholds and a rainfall forecast, running on the device
- Valve control with hard safety limits on maximum continuous and daily runtime
- Dashboard showing moisture history, irrigation events and water used
- A controlled comparison against timer based irrigation over at least 4 weeks, with water use reported
If you have time left
- Sensor calibration against gravimetric soil sampling
- Multiple zones with independent thresholds
- Solar power with a charge controller and measured autonomy
The problem
Most irrigation runs on a timer, which waters during rain and continues through a wet week. Moisture sensors are inexpensive and the control logic is not complicated, so the gap is mostly one of integration.
What you build
A battery powered sensor and control node, decision logic that runs locally, a dashboard, and a measured comparison against a timer.
The design principle that makes it real engineering
The device must work when the network does not. If irrigation depends on a server, a lost connection means either no water or a valve stuck open, and both are serious. Keep the decision logic on the device, treat the forecast as an optional input, and fail into a safe timer based mode.
The safety requirement
Hard limits on valve runtime, enforced in firmware, independent of any logic above. A software bug that leaves a valve open overnight is the failure that matters here, and a maximum runtime that cannot be overridden is the defence.
The result to lead with
Water used per unit of plant health, measured over four weeks against a timer controlled plot. That measurement is the contribution; the hardware is how you obtained it. Start the deployment early enough to collect it.
Scope warning
Two zones at most. Depth of measurement beats breadth of coverage.
Ideas and guidance, not finished projects
These are project ideas and scoping guidance, published free for students to use as a starting point. I do not build, write, or sell final-year projects, and I do not complete coursework for anyone. Take an idea, make it yours, and build it.
Not sure this one fits you?
I help students pick an idea that matches their skills and their deadline, then scope it down until it is finishable. Guidance only, never done for you.
Stuck on something specific?
Writing only gets you so far. If you want an answer to your situation rather than the general case, book a session and we will work through it together. Every session is free; a few slots open each week.
Follow along
New writing, resources and project ideas land here first.