The Build
How We Built SPARSH
SPARSH is a Cartesian CNC drawing robot, built from standard parts available in any Indian electronics market. Here is what it is made of, how it is programmed, and the problems we solved to make it reliable.
What It's Made Of
Bill of Materials
| Component | Purpose | Est. (₹) |
|---|---|---|
| Arduino Board (Brain) | Main controller for all robot operations | 500 |
| NEMA 17 Stepper Motors | Precise, repeatable movement for accurate drawing | 1,200 |
| DRV8825 Stepper Drivers | 32-step microstepping for smoother lines | 150 |
| MG996R / SG90 Servos | Pen lift and automatic tool changer | 450 |
| XYZ Joystick Module | Direct artist input — Co-Creation Mode | 120 |
| LEGO Technic / Acrylic / MDF Frame | Structure — strength, adjustability, stability | 2,000 |
| Lead Screw & Nut | Converts motor rotation to precise linear motion, no backlash | 700 |
| CNC Shield V3 | Connects Arduino to drivers — reduces wiring errors | 250 |
| Limit Switches | Home position and overtravel protection | 100 |
| X-Axis & Y-Axis Gantry Assembly | Cartesian motion — reaches any point on A2 paper | 2,500 |
A complete SPARSH system costs approximately ₹15,000–₹20,000 to build, including the tool changer, 3D-printed parts, and consumables. A single large commissioned artwork can sell for ₹15,000–₹20,000 — so one painting can recover the entire cost of the system.
The Software
SPARSH Engine & Dashboard
The SPARSH dashboard was built in PictoBlox and Python — written entirely by Nysa and Neev. It is the control screen where the artist selects a mode, chooses artwork, monitors the robot, and manages pen and tool changes.
Mode Selection
Triggers the joystick processing loop or the voice recognition listener
Artwork Library
Stores outline coordinate files matched to voice commands via a library index
Voice Command Input
PictoBlox captures the spoken word, matches the library index, sends the design ID
Robot Status
Displays Ready, Drawing, Tool Change, Paused, or Completed
Tool / Colour Status
Shows which tool slot is currently locked
Emergency Stop
Overrides all motor outputs immediately
AI Declaration — WRO Rule 6.5
PictoBlox speech recognition matches spoken words to a fixed design library only — no generative AI is used anywhere in SPARSH. All motion control uses mathematical calculation. Every line of code was written by Nysa and Neev.
What We Tested
Execution Results
Voice Recognition
SPARSH recognised the command "Draw Sunflower" and selected the correct design from the library.
Co-Creation Mode
Artist-controlled joystick movements were accurately converted into CNC drawing motion.
AI-Assisted Mode
SPARSH automatically generated and drew the selected sunflower outline on paper.
Automatic Tool Changer
The robot picked, locked, and switched between different coloured pens without assistance.
X-Y-Z Motion Control
Coordinated X, Y, and Z motion held accuracy across the full drawing area.
Large-Format Artwork
SPARSH produced A2-size artwork while maintaining drawing accuracy throughout.
What We Solved
Challenges We Faced
Voice Recognition in Noise
In noisy rooms the robot misheard commands and picked the wrong shape. We tested across noise conditions, adjusted sensitivity, and trained the recogniser on multiple voices for more reliable matching.
Drawing Accuracy Drift
Over time the movement system loosened and lines drifted from where they should be. We tightened the V-slot connections and drive regularly, and added a calibration check at the start of every session.
Pen Pressure
Different markers press differently — some tore the paper, some drew too faint. We tuned the servo angle limit so the pen meets the paper with the right pressure, and tested across marker types.
Smooth Drawing
Sharp direction changes made corners look rough and jagged. We improved path smoothing in the SPARSH Engine so the robot eases slightly before a hard line change.
Multi-Pen Operation
The tool changer sometimes grabbed the wrong marker or missed the slot. We calibrated each pickup position precisely and added an automatic retry if the first attempt fails.
Built by Two Grade 5 Students
Every part of SPARSH was designed, assembled, coded, and tested by Nysa and Neev — guided by our mentor and shaped by real artists at every step.
Meet the Team