In August 2021, I got an idea to make a robot be able to draw pictures on a wall. After many days researching, designing, and programming, I finally finished a robot that could draw any pattern on a wall.

My key-point in design is using general parts to make robot, so end-users can easily renew parts if repairing is needed. Body frame, motor, bolts and nuts, … are all easily found on the market. Main controller is well-known PCB Arduino Mega compatible with CNC Shield to control two stepper motors that allow robot can traverse by belt.

Step 1: Part List to Prepare

Arduino Mega 2560 x 1pc

CNC shield x 1pc

Power supply PCB x 1pc

SD card module x 1pc

Stepper motor (traverse) x 2pcs

Gear (for belt) x 2pcs

Stepper motor (pen) x 1pc

Belt x 2pcs

Base x 1set

Bolt, nuts (various)

Software

Arduino IDE/ Corel draw/ Microsoft excel

Step1. Install the robot

It takes about 1 hours to assemble the robot.

The first layer is used to install Arduino, CNC shield, power supply.

The second layer will be installed motor, SD card

Next step is prepare for pen-driver and put it to robot

And the final layer is for the face

Put the belt to motor gear and hang it on wall (need 2 nails hammered on wall). Overall, the robot looks like a jellyfish, it is swimming around the wall to make drawing :)

Step 2. Code works

The robot is based on Arduino code for Arduino Mega 2560 and it is open-source. Not like CNC machine which has X, Y axis perpendicular aligned and we can find x, y co-ordinate of target by tracking traverse distance of X, Y stepper motor.

Detail code is here https://github.com/fumikrobot/source-code

The wall drawing robot is hung on wall by 2 nails, we have to find target co-ordinate x1, y1 (of pen) by factor of belt tension (t1, t2), gravity (t3), distance of belt (a, c). Arduino code will help us to solve mathematic problem to find exact current location of pen to make exact drawing

Step 3. Prepare for drawing

After hang robot on wall, we need to do calibration step by declare to Arduino code the distance of two nails. Then, we will prepare drawing as steps:

3.1 Your Picture need to draw

3.2 Convert picture to vector (*.svg file) by CorelDraw (or any other software support *.svg file)

3.3 Convert vector file to code for Arduino (by excel, program by me)

3.4 Copy code file to SD card

3.5 Plug in SD card to robot and start drawing