How to Build a Cute Desktop Companion Robot (That Moves, Blinks & Talks!)

Ever wished your desk had a little more personality?

Meet CAKE, an addorable desktop companion robot that combines tech with an irresistible personality. Unlike traditional robots, CAKE specializes in bringing moments of delight to your day with expressive movements, playful interactions, and gentle wellness reminders.

CAKE doesn't just sit there—it rolls, waves, dances to music, displays custom messages, and even reminds you to take water breaks. With its dual mobility system, mood-based LED animations, and intuitive web interface, this little robot packs serious personality into a beautifully designed package that will become the highlight of your workspace.

All packed into a compact, beautifully customizable form.

PCB & 3D printable Design files included!

Firmware version: v1.24

Powered by an ESP32

Designed in Fusion 360

Why build CAKE?

Bring your desk to life with a robot friend that responds to your presence

Stay on track with gentle fitness and hydration reminders

Express yourself by customizing CAKE's appearance and behaviors

Learn robotics through a fun, approachable project that combines hardware, software, and design

Impress your colleagues with your very own desktop companion (that doesn't eat your snacks!)

Features

Dual mobility: Walk or roll mode with real-time switching

Mood modes with eye/LED animation (e.g., happy, angry, curious)

Sticky Notes: Display custom text via the embedded web UI

Reminders: Schedule water breaks or custom alerts

Time/Date: Real-time clock from ESP32 with auto-sync

Joystick control via responsive local web UI

Auto-reconnect on Wi-Fi restart

Battery level display and servo feedback on GUI (updated every 2s)

Speed settings with simple slider

Plays short melodies or sounds (via speaker)

Power-saving: Auto-disable servo torque in "stand" mode

This step-by-step guide will take you from parts to personality in just a few hours, with detailed instructions suitable for makers of all skill levels. Ready to bake your own CAKE?

Let's get started!

What You'll Need

MCU: ESP32 DevKIT V1 Board

Servos: 4x SC09 Serial Servos (Waveshare or equivalent)

Driver: Waveshare Serial Servo Driver Board

Speaker: MAX98357A DAC with any small Speaker

Display: 2.4" OLED

Lights: Neopixel led Strip

Microphone: INMP mic or I2S (mic included, not yet functional in v1.24)

Proximity: ADPS9960 (gesture / ambient light. not yet functional)

Battery: 2S LiPo 2500mAh or equivalent

Charging: USB-C Charging module and Buck Converter (5V rails)

Mini Buck Converter (5V rails)

Power Button

Connectivity: Wi-Fi AP Mode (ESP32 (no internet required)

Spray Paint of your choice (I use Dark blue, matt black)

And some inner engineering soul with common sense.. etc.

Tools & Materials

3D printer (PLA or PETG recommended)

Soldering iron and solder

Wire cutters/strippers

M3 screws ( 10mm)

Spray paint (optional for custom finish)

Double-sided tape or adhesive

Heat shrink tubing

Basic hand tools (screwdrivers, pliers)

Pro Tip: While exact components are listed, many can be substituted with equivalents. However, if you plan to use the provided PCB design, stick to the specified components for compatibility.

Collect all the mentioned components listed above.

Its not necssarily this components if you can procure them.. you can choose any other similar or equvivalent compotnents.

The exact components are required if You are going on... with PCB (PFA).

The heart of CAKE's aura is its carefully designed chassis that enables both its expressive movements and adorable appearance.

Printing Specifications

1. Resolution: 0.2mm layer height (0.16mm for even smoother finish)
2. Material: PLA or PETG (PLA for beginners, PETG for durability)
3. Infill: 20% for body parts, 40% for mechanical components
4. Support: Required primarily for arm/wheel connections
5. Print Time: Approximately 6-10 hours total across all parts

Essential Components to Print

1. Head Lid
2. Head with mounting points for OLED
3. Wheel caps (2x) - choose between standard or enhanced grip design
4. Feet (1x)

Finishing Touches

For a professional look, consider these optional but recommended finishing steps:

1. Sand key visible surfaces starting with 220 grit, then 400 grit for smooth transitions
2. Prime with plastic-compatible primer (1-2 light coats)
3. Paint with spray paint of your choice (I used dark blue for body, matte black for wheels)
4. Seal with clear matte coating for durability

Designer's Note: The dark blue and black color combination gives CAKE a modern, tech-forward look, but feel free to customize with colors that match your workspace aesthetic!

STL files for the chassis, shell, and wheel clips: Download from GitHub / also attached it here. (PFA)

While you can build CAKE using point-to-point wiring, the custom PCB dramatically simplifies assembly and increases reliability. The PCB handles all the complex interconnections between components and includes mounting points perfectly matched to the 3D printed chassis.

PCB Specifications

1. Layers: 2-layer board
2. Dimensions: 60mm × 40mm
3. Thickness: 1.6mm standard
4. Finish: HASL or ENIG (either works fine)

Ordering Process

1. JUST find the gerber file form my github
2. Upload to your preferred PCB manufacturer (PCBWay, JLCPCB, etc.)
3. Select quantity (3-5 recommended in case of mistakes)
4. Choose standard options (2-layer, 1.6mm, etc.)
5. Total cost is typically around $5-10 plus shipping

Money-Saving Tip: Many PCB manufacturers offer first-time customer discounts. Also consider bundling with other projects to save on shipping!

While You Wait

The PCB typically takes 1-2 weeks to arrive - the perfect time to gather the remaining components and print your chassis!

1. Mount the OLED display in the head cavity with rubber based adhesive
2. you will need M3screws to connect head and lef.
3. lid is snap fit .. but you can also opt for tightning it with m3 screws.
4. I will suggest you to stick the (circular attachment which comes with servo) on the wheel.
5. its the best method and easily removable while working with it.
6. Glue a red wire or a rubber gascket around the wheel for grip and looks.
7. Fit servos on feet and wheels with screws.
8. Dont forget ot mount leds.. it should be glued facing botton.

Precision Tip: Before final assembly, test the fit of each servo in its mount. A drop of light machine oil on mechanical joints will ensure smooth movement for the life of your CAKE!

This is where CAKE begins to come alive! Follow these steps carefully to ensure all electronics work properly.

Servo ID Configuration

Critical Step: Before connecting to the junction board, each servo needs a unique ID:

1. Use the the attached code to ping and set ID to each servo
2. Assign IDs as follows:
3. ID 1: Left arm/foot
4. ID 2: Left wheel
5. ID 3: Right arm/foot
6. ID 4: Right wheel
7. Connect servos to junction board and driver
8. Mount speaker, mic, OLED, Neopixel, and ADPS to ESP32
9. Power ESP32 (2) via regulated 5V from the buck converter
10. Install the battery and toggle switch
11. Optional: wire headphone jack for alternate audio output
12. I had attached schematics of pcb.

PFA: A detailed connection table is available in the GITHUB repo

^you will need to ping and set if to each servo individually by connecting it one by one to the driver.

Pro Wiring Tip: Use different colored wires for power (red), ground (black), and signals (various colors) to make future maintenance easier. Label any non-standard connections!

Flash using Arduino IDE / Arduino Cloud

(Validated and uploaded with arduino IDE 2.3.6) / (Arduino Cloud)

There are 2 separate code (.ino) files for ESP1 and ESP2

(Some preview..)

On first boot:

1. servo move to neutral
2. Wheels (2/4) move to stand pose
3. Torque turns off after 1 second
4. Battery and servo feedback start updating

Let's get to know CAKE's controls and customize it to your preferences!

Connecting to CAKE

1. On your smartphone or computer, connect to the WiFi network:
2. SSID: CAKE_ROBOT
3. Password: 12121212
4. Open a web browser and navigate to: 192.168.4.1
5. The CAKE control interface should appear

Basic Controls

The intuitive web interface gives you complete control:

1. Movement:
2. Directional pad for forward/backward motion
3. Tilt controls for expressive movements
4. Speed slider to adjust movement rate
5. Expressions:
6. Toggle between Happy, Curious, Sleepy, or Angry eye animations
7. Custom animation sequences for special occasions
8. LED Control:
9. Color picker for static lighting
10. Animation modes (pulse, rainbow, mood-based)
11. Brightness control
12. Sticky Notes:
13. Enter custom text messages to display
14. Schedule messages to appear at specific times
15. Choose from preset encouraging messages

Wellness Reminders

CAKE can be your wellness buddy too:

1. Set hydration reminders (30-90 minute intervals)
2. Create custom reminders for medications or other needs
3. 
   

Controls:

1. Motion: Forward/backward, tilt left/right
2. Eyes: Angry, happy, sleepy modes
3. LEDs: Pulse, static, or mood-based colors
4. Reminders: Set timer-based alerts

Congratulations on creating your very own CAKE desktop companion! From a collection of parts to an adorable, interactive robot friend, you've completed a project that combines electronics, programming, and design into something truly special.

CAKE is designed to grow with you - as your skills improve, you can enhance its capabilities with new features and customizations. We can't wait to see how your CAKE becomes part of your daily routine and workspace!

Experiment with animations, add sensors, or program new behaviors via the web interface!

Future Development

The CAKE project is constantly evolving! Coming soon:

1. Voice control capabilities
2. Advanced gesture recognition
3. Multi-CAKE synchronized movements
4. Mobile app control interface