2 layers77 × 39 mm
2 layers61 × 36 mm
RIO Mega-328
zetapersei/Wifi-ATmega328Simple board with esp8266 + ATMega328
- Size
- 61 × 36 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 33
- Nets
- 52
- Pads
- 174
- Tracks, vias
- 341, 21
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 13 Feb 2022
- Updated
- 3 Nov 2026
Overview
RIO Mega-328 is an open-source printed circuit board by zetapersei, from the zetapersei/Wifi-ATmega328 repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 61 × 36 mm with 33 parts on 52 nets, routed with 341 tracks and 21 vias.
It is built around the ATMEGA328P-PU, ESP-12F and XL1509-ADJE1, with the B5819W among its other parts. Its parts include 9 capacitors, 8 resistors, 4 connectors, 3 ICs and 3 diodes. It belongs with the ESP8266 and AVR (ATmega, ATtiny) boards of this library.
Main components
4
ATMEGA328P-PU
DIP-28-300mil-40℃~+85℃ 1.8V~5.5V 10bit 1KB 20MHz 23 2KB 32KB 8 Bit AVR Built-in FLASH DIP-28-300mil Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
ESP-12F
SMD,24x16mm-40℃~+85℃ -96dBm 15dBm 2.4GHz 3.3V 375mA 55mA PCB UART WIFI4 SMD,24x16mm WiFi Modules ROHSDOITWiFi Modules
XL1509-ADJE1
SOIC-8-40℃~+85℃ 1 1.23V~37V 127kHz~173kHz 2A 2mA 4.5V~40V Adjustable Buck Buck Built-in No SOIC-8 DC-DC Converters ROHSXLSEMIDC-DC Converters
B5819W
SOD-123-55℃~+125℃ 1.5A 1mA@40V 25A 40V 600mV@1A Standalone SOD-123 Schottky Diodes ROHSMDDSchottky Diodes
README
README.mdWifi-ATmega328
A compact embedded board that combines an ESP8266 Wi-Fi module with an ATmega328P microcontroller for projects that need low-cost wireless connectivity and simple MCU control.
Overview
This project provides a custom PCB designed for applications where an ATmega328P handles the logic and an ESP8266 provides Wi-Fi communication. The design is intended for embedded systems, IoT prototypes, sensor gateways, and small control boards that need a lightweight microcontroller plus wireless connectivity.
The board includes:
- ESP8266 Wi-Fi module
- ATmega328P microcontroller
- power regulation from a 12V / 5V input to the required logic voltages
- ICSP programming interface for the ATmega328P
- KiCad hardware design files for modification and reproduction
Hardware architecture
The board is built around two processing elements:
- ATmega328P: used for application logic, sensor acquisition, timers, and control tasks
- ESP8266: used for Wi-Fi communication, network connectivity, and possible ESP-Now communication
The supplied power stage converts the board supply into the voltage levels required by the modules. A dedicated ICSP connector allows the ATmega328P to be programmed directly without removing it from the board.
The hardware project is available in the hardware folder and includes the KiCad schematic and PCB files.
Software options
The ESP8266 can be used with the AT command firmware, enabling communication with the ATmega328P through serial interfaces. In this setup, the MCU can delegate Wi-Fi tasks to the ESP8266 while continuing to handle local logic.
Recommended software paths:
- WiFiEspAT library for AT firmware-based Wi-Fi communication
- WiFiESPNow library for ESP-Now communication scenarios
This makes the board suitable for both classic serial-controlled Wi-Fi use and low-latency peer-to-peer wireless communication.
Repository structure
hardware/— KiCad project files and PCB design assetsREADME.md— project overview and documentationLICENSE— project license information
Board views
Top view
Isometric view
Typical use cases
- wireless sensor nodes
- smart actuator control boards
- IoT prototypes and test platforms
- embedded projects that need a classic AVR MCU plus Wi-Fi access
This board is especially useful when an AVR-based firmware stack is preferred while still requiring network connectivity through the ESP8266.
Parts
33| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 10k | Resistor_SMD:R_0402_1005Metric | R3, R5, R6, R7, R8 |
| 4 | 100nF | Capacitor_SMD:C_0402_1005Metric | C2, C4, C7, C9 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_2.5mm_Pad_Via | H1, H2, H3, H4 |
| 2 | 22pF | Capacitor_SMD:C_0402_1005Metric | C5, C6 |
| 1 | 1.8k | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 10uF | Capacitor_SMD:C_0603_1608Metric | C8 |
| 1 | 16Mhz | Crystal:Crystal_HC18-U_Vertical | Y1 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric | R4 |
| 1 | 1N4148 | Diode_SMD:D_SOD-123F | D2 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 330uF/35V | Capacitor_THT:CP_Radial_D8.0mm_P5.00mm | C3 |
| 1 | 470uF/35V | Capacitor_THT:CP_Radial_D8.0mm_P5.00mm | C1 |
| 1 | 47uH/2A | JLCPCB:L_6.0x6.0x4.5-SWPA-Sunlord | L1 |
| 1 | ATmega328P-PU | Package_DIP:DIP-28_W7.62mm | U2 |
| 1 | B5819W | Diode_SMD:D_SOD-123F | D1 |
| 1 | ESP Prog | Connector_PinHeader_2.54mm:PinHeader_2x05_P2.54mm_Vertical | J2 |
| 1 | ESP-12F | RF_Module:ESP-12E | U3 |
| 1 | GPIO1 | Connector_PinHeader_2.54mm:PinHeader_2x04_P2.54mm_Vertical | J3 |
| 1 | GPIO2 | Connector_PinHeader_2.54mm:PinHeader_2x06_P2.54mm_Vertical | J4 |
| 1 | ICSP | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J1 |
| 1 | M7 | Diode_SMD:D_SOD-128 | D3 |
| 1 | XL1509-ADJE1 | Package_SO:SOP-8_3.9x4.9mm_P1.27mm | U1 |
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51 parts
Questions
How big is the RIO Mega-328 PCB?
It measures 61 × 36 mm and has 2 copper layers, 1.6 mm thick.
What parts does the RIO Mega-328 use?
33 parts, built around the ATMEGA328P-PU, ESP-12F, XL1509-ADJE1 and B5819W. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the RIO Mega-328 KiCad files?
From the zetapersei/Wifi-ATmega328 repository on GitHub, at the commit this page was made from: the board is hardware/RIO-Mega-328.kicad_pcb and its schematic hardware/RIO-Mega-328.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the RIO Mega-328 design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).