Hardware Setup

Microcontroller Options

ESP32-C3 Super Mini (Current)

The ESP32-C3 Super Mini is a compact development board with excellent performance for this project.

XIAO ESP32-C6 (Recommended Upgrade)

The XIAO ESP32-C6 offers significant improvements:

• 13-14% better battery life due to improved power efficiency
• WiFi 6 support for enhanced connectivity
• Identical pinout - plug-and-play upgrade from ESP32-C3
• Enhanced performance with more memory and faster processing

💡 Both boards use the same wiring and code - choose based on availability and requirements.

ESP32-C3 Super Mini Pin Layout

Pin Layout

The ESP32-C3 Super Mini is a compact development board with the following pin assignments:

General Purpose Pins

Pin	GPIO	Function	Notes
A0	0	Analog/Digital
A1	1	Analog/Digital
A2	2	Digital	Used for E-Paper BUSY
A3	3	Digital	Used for E-Paper CS
A4	4	Digital	User Button (shares with SCK)
A5	5	Digital	Shares with MISO
GPIO10	10	Digital	General purpose

Communication Pins

Pin	GPIO	Function	Notes
SCK	4	SPI Clock	Shared with A4/User Button
MISO	5	SPI MISO	Shared with A5
MOSI	6	SPI MOSI	Used for E-Paper SDI
SS	7	SPI Chip Select	General purpose
SDA	8	I2C Data	Used for E-Paper RES
SCL	9	I2C Clock	Used for E-Paper DC
RX	20	UART Receive	Serial communication
TX	21	UART Transmit	Serial communication

E-Paper Display Wiring

Required Connections

The e-paper display requires 6 GPIO pins + 3.3V + Ground (total 8 pins):

E-Paper Pin	ESP32-C3 Pin	GPIO	Function
BUSY	A2	2	Busy signal
CS	A3	3	Chip Select
SCK	SCK	4	SPI Clock
SDI	MOSI	6	SPI Data In
RES	SDA	8	Reset
DC	SCL	9	Data/Command
3.3V	3.3V	-	Power supply
GND	GND	-	Ground

Wiring Diagram

ESP32-C3 Super Mini          E-Paper Display
┌─────────────────┐         ┌─────────────────┐
│ 3.3V      ●─────┼─────────┼─● 3.3V          │
│ GND       ●─────┼─────────┼─● GND           │
│ GPIO 2    ●─────┼─────────┼─● BUSY          │
│ GPIO 3    ●─────┼─────────┼─● CS            │
│ GPIO 4    ●─────┼─────────┼─● SCK           │
│ GPIO 6    ●─────┼─────────┼─● SDI           │
│ GPIO 8    ●─────┼─────────┼─● RES           │
│ GPIO 9    ●─────┼─────────┼─● DC            │
└─────────────────┘         └─────────────────┘

Pin Conflicts

⚠️ Important Pin Sharing Notes:

• GPIO 4: Shared between SPI SCK and User Button
• GPIO 5: Shared between SPI MISO and A5
• GPIO 8: Shared between I2C SDA and E-Paper RES
• GPIO 9: Shared between I2C SCL and E-Paper DC

Power Supply

Power Options

1. USB-C: 5V input, regulated to 3.3V on-board
2. Battery: 3.7V LiPo battery (JST connector if available)
3. External 3.3V: Direct 3.3V supply to 3.3V pin

Power Consumption

• Active mode: ~80-120mA (WiFi + display update)
• Deep sleep: ~10-50μA (depending on configuration)
• Estimated battery life:
  • 2000mAh battery: 2-4 weeks (5-minute update intervals)
  • 1000mAh battery: 1-2 weeks (5-minute update intervals)

Assembly Tips

Soldering

1. Use flux for clean solder joints
2. Start with power connections (3.3V, GND)
3. Double-check polarity before powering on
4. Test continuity with multimeter

Enclosure Considerations

• Ensure antenna clearance for WiFi
• Provide access to USB-C for programming
• Consider heat dissipation during operation
• Protect against moisture if used outdoors

Testing

1. Power test: Verify 3.3V supply
2. SPI test: Check e-paper display communication
3. WiFi test: Verify network connectivity
4. Full system test: Run complete firmware

Troubleshooting Hardware Issues

Display Not Working

• Check all 8 connections (6 GPIO + power)
• Verify 3.3V power supply stability
• Ensure proper SPI timing (check SCK signal)

WiFi Connection Issues

• Check antenna clearance
• Verify power supply stability during transmission
• Ensure proper grounding

Power Issues

• Measure actual power consumption vs. expected
• Check for shorts or incorrect wiring
• Verify deep sleep functionality