Automatic Wall Painting Robot

Painting is one of the most labour-intensive and hazardous jobs in construction: workers spend long hours on scaffolding breathing paint fumes, coverage quality varies from person to person, and large flat surfaces eat time that could be automated. The industry has mechanized cutting, mixing, and lifting — but the paint roller is still largely manual. A wall-painting robot attacks the most repetitive slice of the job: moving a sprayer across a flat panel at constant speed with even overlap. Building one forces students to combine motion sequencing, fluid delivery, and coverage planning in a single machine, and the result is unusually legible — anyone can judge the before-and-after panel. Construction robotics is a growing field, and a robot that visibly paints a wall gives students a concrete entry point into it.

The vertical rail frame is positioned against the wall panel and the paint reservoir is filled.
In auto mode, the Arduino starts the sprayer pump to pressurize the nozzle.
A motor drives the carriage upward along the rails while the nozzle sprays a vertical strip.
At the top limit switch, spraying pauses and the carriage steps horizontally to the next strip position.
The carriage descends, spraying the next strip with slight overlap for uniform coverage.
The cycle repeats until the full panel width is covered, then motion and spraying stop.
Manual mode lets the operator jog the carriage and trigger the sprayer independently.

Rail-mounted robot carriage with controlled vertical and horizontal motion
Motorized sprayer pump + nozzle for even, consistent paint coating
Arduino-controlled motion sequencing: pass, shift, next pass
Adjustable spray timing and carriage speed for coverage control
Paint reservoir with level indication and easy refill
Limit switches for safe carriage travel at rail ends
Manual/auto mode selection for demonstration flexibility
Emergency stop button for instant halt of motion and spraying
Even-coverage demo on a wall panel — visible before/after result
Modular rail frame: assembles and disassembles for transport to the review

Working wall-painting robot with rail frame and carriage
Sprayer pump, nozzle, reservoir and tubing assembly
Arduino firmware (auto sequence + manual jog mode)
Mechanical assembly diagrams + electrical wiring diagram
Project report PDF (construction-automation survey, design, coverage-test procedure, conclusion)
PPT presentation
Viva Q&A preparation document (spray dynamics, motion control, coverage planning, safety)

FAQs

1. How even is the paint coverage? Successive vertical strips overlap at a constant, tuned carriage speed, producing visibly uniform coating on flat panels. The report documents the procedure for comparing robot-coated and manually coated sections.
2. What kind of paint can it use? Water-based paints within the diaphragm pump's viscosity range. Thick paints risk clogging the nozzle — the report specifies the recommended paint and thinning ratio.
3. How does it avoid drips and runs? Constant carriage speed and controlled spray timing keep the paint film thin; nozzle distance from the wall is fixed by the carriage geometry, and dwell time at strip ends is minimized by the motion sequence.
4. Is it safe to operate? The emergency stop halts both motion and spraying instantly, limit switches prevent over-travel, and the low-voltage DC system is safe to handle during a demo.
5. Why paint in overlapping vertical strips? Overlap compensates for the spray pattern's tapered edges — each pass's thin edge is covered by the next pass's full coat — which is the standard technique for uniform coverage in spray applications.