Build Your Own Mehandi Design Robot!
Turn a few motors, some cardboard, and a marker pen into a robot that draws beautiful spiral henna-style mandala patterns — all by itself! No prior coding experience needed.
📋 What's inside this project
🧰 What You'll Need
Gather these simple parts before you start. Most are available at any local electronics or craft shop.
Arduino Uno board
The "brain" that controls both motors.
Continuous rotation servo
Spins the paper turntable round and round.
Micro servo (SG90)
Lifts the pen up and down between circles.
Jumper wires (x6)
Connects the servos to the Arduino board.
Cardboard or thin plywood base
A sturdy platform, about 20×20 cm.
Round disc (old CD or cardboard circle)
The turntable your paper design sits on.
Washable marker pen
Draws the design — no real henna paste needed!
9V battery + clip (or USB power)
Powers the Arduino independently.
Craft glue gun, tape, rubber bands
For assembling the frame (adult supervision).
⚙️ How Does It Work?
Real henna artists draw mandalas by turning the hand or the paper slowly while tracing loops outward from the centre. Our robot copies this exact idea using two motors:
1. The turntable servo spins the paper round and round, just like a lazy Susan.
2. The pen-lift servo raises and lowers the marker between each circle, so every loop the robot draws lands at a slightly bigger distance from the centre.
Together, spin after spin, these simple motions build up a layered spiral pattern that looks a lot like a traditional henna mandala — drawn entirely by your robot!
🔌 The Circuit Diagram
Both servos are powered directly from the Arduino's 5V pin and controlled through two digital pins.
| Arduino Pin | Connects To | Wire Colour (suggested) |
|---|---|---|
| 5V | Both servos — Power (+) | Red |
| GND | Both servos — Ground (–) | Black |
| Pin 9 | Turntable servo — Signal | Yellow / Orange |
| Pin 10 | Pen-lift servo — Signal | Yellow / Orange |
🛠️ Let's Build It — Step by Step
Prepare the base
Cut a 20×20 cm square from cardboard or thin plywood. This will hold both servos and the turntable.
Mount the turntable servo
Glue the continuous rotation servo to the centre of the base. Attach the round disc firmly to the servo horn so it spins evenly.
Build the pen-arm
Attach the micro servo to a small wooden arm positioned above the turntable's edge. Tape the marker pen to the servo horn so it can swing down to touch the paper.
Cut your paper circle
Cut a plain white paper circle to match the size of your turntable disc, and tape it lightly in place.
Wire the circuit
With an adult's help, connect both servos to the Arduino exactly as shown in the circuit diagram above.
Upload the code
Connect the Arduino to your computer, open the Arduino IDE, and upload the sketch from the next section.
Do a test run
Power the robot and watch it spin the first circle. Adjust the pen-arm position slightly outward before each new loop.
Decorate and admire
Once the layered spiral is complete, gently lift the paper off — you've got your very own robot-made mehandi mandala!
💻 Time to Code!
This beginner Arduino sketch controls both servos: one spins the turntable, the other lifts the pen between circles.
Open the Arduino IDE, paste this code, select Tools → Board → Arduino Uno, and click Upload.
// Mehndi Magic Bot — draws a layered spiral mandala pattern // Uses two servos: one spins the turntable, one lifts the pen #include <Servo.h> Servo turntable; // continuous rotation servo Servo penLift; // micro servo for pen up/down const int turntablePin = 9; const int penPin = 10; const int stopSpeed = 90; // stop signal for continuous servo const int spinSpeed = 60; // slow, steady spin const int penDown = 40; // angle: pen touching paper const int penUp = 90; // angle: pen lifted away void setup() { turntable.attach(turntablePin); penLift.attach(penPin); turntable.write(stopSpeed); // make sure turntable starts still penLift.write(penUp); // start with pen lifted delay(1000); } void loop() { drawOneCircle(); delay(5000); // pause — slide the pen-arm outward by hand here } void drawOneCircle() { penLift.write(penDown); // lower the pen onto the paper delay(500); turntable.write(spinSpeed); // start spinning the turntable delay(3000); // tune this for one full rotation turntable.write(stopSpeed); // stop spinning penLift.write(penUp); // lift the pen back up delay(500); }
delay(3000) controls how long one spin lasts. Time your servo with a stopwatch and adjust until it completes exactly one full turn.spinSpeed to a smaller number (like 70) for a slower, more detailed pattern.🛡️ Safety First
Keep it safe while you build and play:
- Ask an adult to help with the glue gun, scissors, and wiring.
- Use a washable marker pen, not real henna paste, so the project stays mess-free and skin-safe.
- Keep fingers away from the servo horn while it's spinning to avoid pinches.
- Always disconnect the battery before changing any wiring.
- If you'd like to try real henna paste later, do it only with adult supervision and a proper cone applicator — never near the electronics.
✨ Fun Mehandi Facts
A little history to share while your robot draws.
years old — mehandi art traces back to ancient Egypt and South Asia.
Henna comes from the leaves of the Lawsonia inermis plant.
Spiral and mandala patterns symbolise good luck and joy in many cultures.
Mehandi is traditionally applied during weddings and festivals.
❓ Frequently Asked Questions
What is a mehandi design robot?
It's a simple homemade machine that uses motors controlled by an Arduino to spin a paper turntable and move a pen, drawing spiral mandala patterns similar to traditional henna art.
Do I need coding experience to build this robot?
Not at all. The Arduino sketch above is short, fully commented, and explained line by line — a great first project for beginners.
Is it safe for kids to build this robot?
Yes, as long as an adult helps with the glue gun, scissors, and wiring. The project uses a washable marker instead of real henna paste, so it's clean and skin-safe.
What parts do I need for the mehandi robot?
An Arduino Uno, a continuous rotation servo, a regular micro servo, jumper wires, a cardboard or wooden base, a round turntable, and a washable marker pen.
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