# Heltec WiFi Kit 8

> ESP8266-based IoT development board by Heltec with built-in 0.91-inch OLED display, Li-Po battery management, and WiFi connectivity in a compact 50.9x18.2mm form factor.

## Quick Facts

- **Brand:** Heltec
- **Board Type:** Development Board
- **Price:** ~$7.59
- **Product Readiness:** developer
- **CPU:** ESP8266
- **CPU Architecture:** Xtensa
- **CPU Cores:** 1
- **RAM:** 520 KB
- **Flash:** 4 MB
- **Power:** 5V via Micro USB
- **Operating Voltage:** 3.3V
- **Antenna:** built-in PCB antenna
- **SD Card:** No
- **Display:** 0.91" OLED 128×32

## Connectivity

- **Wifi:** 802.11n

## Open Source

- **Firmware:** No
- **Schematics:** Yes
- **PCB Layout:** No

## Compatible Firmware

arduino, platformio, micropython, esp-idf

## Use Cases

- iot
- smart-home
- environmental-monitoring
- educational-platform

## Components

- **ESP8266** (mcu): Espressif ESP8266 single-core Tensilica L06 SoC at 160 MHz with WiFi 802.11n — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.espressif.com%2Fsites%2Fdefault%2Ffiles%2Fdocumentation%2F0a-esp8266ex_datasheet_en.pdf&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- **SSD1306** (display-driver): Solomon Systech SSD1306 OLED/PLED driver with 128×64 max resolution, I2C/SPI interface — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fcdn-shop.adafruit.com%2Fdatasheets%2FSSD1306.pdf&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- **CP2104** (usb-uart): Silicon Labs CP2104 USB-to-UART bridge for programming and serial debug — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.silabs.com%2Fdocuments%2Fpublic%2Fdata-sheets%2Fcp2104.pdf&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)

## Protocols

- **UART**
- **SPI**
- **I2C**
- **I2S**

## Description

## Overview

The Heltec WiFi Kit 8 is a compact IoT development board built around the ESP8266 microcontroller. It integrates a 0.91-inch 128×32 OLED display, lithium battery management system, and 2.4 GHz WiFi — making it ideal for smart home, environmental monitoring, and IoT maker projects.

## Key Features

- **ESP8266 MCU** running at 160 MHz (Tensilica L06 core) with 4MB flash and 520KB SRAM
- **0.91" OLED Display** with 128×32 resolution for status output and data visualization
- **Integrated Li-Po battery management** with charge/discharge control, overcharge protection, battery detection, and USB/battery auto-switching via SH1.25×2 connector
- **WiFi 802.11n** at 2.4 GHz with up to 72.2 Mbps throughput
- **17 GPIOs** with UART (×2), SPI (×2), I2C, I2S, and 10-bit ADC
- **Micro USB** with voltage regulation, ESD protection, short circuit protection, and RF shielding
- **CP2104 USB-to-Serial** bridge for programming and debugging
- **Onboard 2.4 GHz PCB antenna**

## Specifications

| Spec | Value |
|------|-------|
| MCU | ESP8266 (160 MHz Tensilica L06) |
| Flash | 4 MB (32M-bits SPI) |
| SRAM | 520 KB |
| Display | 0.91" OLED, 128×32 |
| WiFi | 802.11n, 2.4 GHz, up to 72.2 Mbps |
| GPIO | 17 |
| Interfaces | UART ×2, SPI ×2, I2C ×1, I2S ×1, ADC ×1 (10-bit) |
| USB | Micro USB (CP2104 bridge) |
| Battery | 3.7V Li-Po (SH1.25×2 socket) |
| Dimensions | 50.9 × 18.2 × 8 mm |
| Weight | 15 g |
| Operating Temp | -20°C to 70°C |

## Packing List

- WiFi Kit 8 board ×1
- Glue rod antenna ×1
- SH1.25×2 battery connector ×1

## Resources

- [Pinout Diagram (PDF)](https://resource.heltec.cn/download/WiFi_Kit_8/WIFI_Kit_8_Pinout_Diagram.pdf)
- [Schematic Diagram (PDF)](https://resource.heltec.cn/download/WiFi_Kit_8/WIFI_Kit_8_Schematic_diagram.pdf)
- [Heltec Documentation Wiki](https://wiki.heltec.org/)

## Where to Buy

- [Buy for $7.59](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Fwifi-kit-8%2F&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)

## Resources

- [official](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Fwifi-kit-8%2F&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- [product](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Fwifi-kit-8%2F&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- [documentation](https://openhardware.directory/r?to=https%3A%2F%2Fwiki.heltec.org%2F&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- [schematic](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FWiFi_Kit_8%2FWIFI_Kit_8_Schematic_diagram.pdf&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)
- [pinout](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FWiFi_Kit_8%2FWIFI_Kit_8_Pinout_Diagram.pdf&ref=openhardware.directory&product=heltec-wifi-kit-8&source=md-export)

## Tags

`esp8266`, `oled`, `wifi`, `iot`, `dev-board`, `heltec`, `battery-management`, `compact`

## Images

![Heltec WiFi Kit 8](https://heltec.org/wp-content/uploads/2023/10/SAM_0658_800X800-1.png)

> **Battery Powered:** Li-Po 3.7V

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