SmartCube is a tinly and customizable desk toy using the ESP8266 D1 Mini. It features a rechargeable power supply, three input buttons, an SSD1306 OLED display and a 20mm piezo buzzer for sound.

Info

Code: I have a few projects developed for the cube. You can see the list here on my Gitea
Case: 3D-printable design included in /hardware directory
Schematics: and assembly instructions are also in the /hardware directory

Bill of Materials

Component	Quantity	Description	Notes
ESP8266 D1 Mini	1	Microcontroller module
SSD1306 OLED Display	1	128x64 resolution, I2C interface
14250 Rechargeable Battery	1	Lithium-ion battery	Make sure you get the rechargeable type, most 14250 are not
TP4056 Module	1	Charging and protection circuit	Does not need to have a USB connector
Push Buttons	3	Tactile push buttons
Piezo Buzzer	1	Buzzer for audio feedback
Resistors (10kΩ)	3	Pull-down resistors for buttons	Ensures stable button input
Wires	Several	For connections
Enclosure	1	3D-printed or custom-made case	3D printable STL files are in `hardware/case/`
2x6mm screw	12	Small screws for seembling the case	Does not have to be exactly 6mm long

Demo Code Explanation

The provided demo code is the starting point(hello world) for the SmartCube development with Platform.io, it does the basic system initialization, button handling, OLED display output configured, and WiFi management:

Key Features

WiFi Management:
- The cubeWifiManager class manages WiFi connectivity seamlessly.
- If no known WiFi network is available, it starts a configuration portal and creates an access point (AP), allowing users to connect the SmartCube to a network from another WiFi-enabled device.
- The OLED display shows the access point details, such as the AP name and IP address, making the setup process very easy.
Button Handling:
- Buttons are mapped to specific GPIO pins: PIN_BTN_L (Left), PIN_BTN_M (Middle), and PIN_BTN_R (Right).
- The cubeButtonHandler() function, executed in the loop(), monitors and interprets button presses, differentiating between short and long presses.

Default Button Actions

Right Button:
- Short Press: Turns the OLED display on (if previously off).
- Long Press: Turns the OLED display off, helping conserve power.
Left + Middle Buttons (Simultaneous Long Press):
- Triggers an ESP8266 reboot, effectively restarting the device.

Pin Connections

OLED Display Settings

#define SCREEN_WIDTH 128  
#define SCREEN_HEIGHT 64  
#define OLED_RESET -1  
#define FRAMERATE 8

The OLED display is connected via I2C to the D1 Mini:

SDA: D2 (GPIO4)
SCL: D1 (GPIO5)

Buttons and Buzzer

#define PIN_BTN_L 12 // D6  
#define PIN_BTN_M 13 // D7  
#define PIN_BTN_R 15 // D8  
#define PIN_BUZZER 0 // D3

Button Left (PIN_BTN_L): GPIO12
Button Middle (PIN_BTN_M): GPIO13
Button Right (PIN_BTN_R): GPIO15
Piezo Buzzer (PIN_BUZZER): GPIO0

Assembly Instructions

Power Supply Setup:
- Solder the 14250 battery to the TP4056 module input pins.
- Wire the output of the TP4056 to the 3.3V pin on the D1 Mini to power the device.
- Connect the 5V output pin from the D1 Mini to the input port on the TP4056 module to allow charging trough the Data USB port on the ESP8266.
OLED Display: Solder connections for SDA (D2, GPIO4) and SCL (D1, GPIO5) to the respective pins on the D1 Mini.
Buttons: Attach each button to the specified GPIO pins with pull-down resistors to ensure reliable input.
Buzzer: Connect the piezo buzzer, negative to the GPI00, positive to 3.3v
Enclosure: Assemble all components in a secure housing. May require some hot glue to keep components in

Notes

This is still a work in progress
Everything is pretty tightly packed in there and it's a mess. But it's not as hard to make as it looks.
Ensure all connections are secure. Hot glue is your friend.
Test the circuit thoroughly before placing and glueing it in the enclosure.
Battery is the trickiest part to fit in, it's best to glue the charging module directly to it and put it in the case last

For questions or additional details, feel free to reach out!