Telescopic watering can
Six-person group project carried out in late 2025 during my first year at EPF, as part of an innovation challenge: designing a watering can that reaches hard-to-access plants (hanging baskets, tall hedges, wall planters) without a ladder.
The need
The functional specification targets private individuals, tenants who cannot install automatic watering, amateur gardeners, small businesses (florists, schools, associations) and elderly people or people with reduced mobility who want to avoid carrying heavy loads or climbing a ladder.
The analysis of existing products revealed the missing link. A classic watering can has a limited reach and becomes risky when lifted full above your head. Watering poles are heavy and unstable. Backpack sprayers mean carrying several kilos. Automatic systems are expensive, noisy and hard to set up at home.
The specification
The functional specification (version 3) focuses on the "what" rather than the "how":
- water at a nozzle height of at least 2.50 m, with a pressure of at least 0.25 bar;
- hold up to 8 L of water, with an empty mass of 2.5 kg at most;
- be usable and carried by a single person, with one-handed spray adjustment;
- run only on the user's own energy, with an effort below 30 N;
- stay easy to maintain: an opening of at least 80 mm and parts that come apart without tools.
Design process
After the specification, the team deliberately widened the range of ideas (brainstorming, mind maps) before converging. Two inspirations shaped the concept: the rings of a fishing rod, to guide the hose along the mast, and the piston pump of inflatable mattresses, to pressurize the water without electricity.
Each subsystem was then decided with a Pugh matrix against a reference (a sprayer can with a diaphragm pump). The pedal beat the push button, the crank and the lever; the piston pump beat the diaphragm, screw and centrifugal pumps; plastic beat aluminium and stainless steel; and a flexible hose with a rigid nozzle beat fixed nozzles.
Four technical hurdles were solved:
- Pressurizing: a pedal-driven piston pump, with intake and discharge valves that turn muscle effort into pressure in the tank.
- The hose: an automatic reel connected to the pump through a hollow-shaft rotary joint with O-rings, for a watertight link between the fixed part and the spinning drum.
- Stability: a lowered centre of gravity by putting the heavy mechanics in the base, and a ground triangulation with wide-set wheels and a flared rear foot.
- Guiding at height: a telescopic mast fitted with rings that follow the hose as it extends, with no tangling.
Chosen solution
- Metal telescopic mast, maximum extension 2.50 m, stored at 1.20 m
- 8 L tank (10.5 kg full, 2.5 kg empty)
- Built-in manual piston pump (0.3 bar, 1.5 L/min)
- Adjustable nozzle (jet / shower)
- Compact automatic hose reel and swivelling front wheels for mobility
What the project taught me
Innovating also means dropping good ideas to keep only the one that best meets the need. The project was also an exercise in running a project: splitting the work into tasks and using a Gantt chart to meet the successive deadlines.
The full details (needs, decision matrices, planning and drawings) are available in the documents below.
Documents
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Functional specification (PDF)
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Pugh matrix (PDF)
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Planning and retrospective (PDF)
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Full technical diagrams (PDF)