Soil and water node
A small outdoor box that watches soil moisture, a pump and a water tank, and sends simple irrigation alerts. Solar-ready. Built to keep working on a poor connection.
Sketch of the plan, not a photo. Not built yet.
What it is
A weather-sealed node on a stake. It reads soil moisture, checks whether the pump is running and how full the tank is, and tells you when something needs attention.
It is designed for a bad day: little sun, weak signal, nobody around. It stores readings locally and sends them when it can.
Why build it
Watering by guesswork wastes water and kills plants in both directions. A cheap, tough node is the most useful first sensor for a yard.
It is also the right first two-yards build. Almost every part of it can be affected by place: the soil, the sun, the signal, the parts shelf and the radio rules.
The plan, step by step
This is the plan as it stands. Steps get rewritten as the build teaches us things.
- 01
Decide what it measures
Soil moisture, pump state and tank level. Nothing else in version one. Every extra sensor is one more thing to seal.
- 02
Build it on the bench
Breadboard first. Get stable readings from each sensor on its own before joining them up.
- 03
Plan for a poor connection
Store readings on the node. Send small, send rarely, and retry without draining the battery. An alert that arrives late still has to make sense.
- 04
Design the power budget
Work out what it draws awake and asleep, then size the battery and leave a clean way to add a solar panel.
- 05
Seal it and stake it
Enclosure, cable entries, strain relief, and a mount that survives being bumped. Printed parts where they help.
- 06
Calibrate in real soil
Bench numbers mean little. Calibrate against the soil it will live in, in each yard.
- 07
Install in both yards
Same plan, same parts where possible. Every substitution gets written down with the reason.
- 08
Log the lessons
Each lesson goes into Universal, Geographic or Rules, with its evidence.
Questions this build should answer
Installed in Southern California and in Ghana. These are questions, not answers. The answers get logged when both yards have run.
Universal
- Where in the soil should the sensor sit to give a reading you can act on?
- How often does it need recalibrating?
- Which seals and cable entries actually keep water out?
- What does a “needs water” signal look like in the data, compared with noise?
Geographic
- How do heat, humidity, rain and dust change what fails first?
- How much does solar yield differ between the yards, and what does that do to the power budget?
- What does mobile coverage allow in each yard, and how long are the gaps?
- Which parts can be bought locally in each place, and what gets substituted?
Rules
- Which radio bands and power levels are allowed in each place?
- What do import duties and shipping do to the parts list?
- Does storing yard data raise any data-protection questions?
- Are there water-use rules that change what the node should alert on?
Indoor starts to yard
Raising vegetable and pepper starts indoors, then moving them outside without losing them. The gadget angle: knowing when a start is ready, and when the yard is.
Backyard squirt turret
A pan-and-tilt water squirter for the yard. Low pressure, plain water, entirely silly. A fun way to learn motion control outdoors.