Very small and breadboard-friendly with option of male, female or both (stackable headers). Includes a dual-core 240 MHz ESP32 with WiFi and Bluetooth. You can use the WiFi both in station (device) mode and access point mode. It includes traditional Bluetooth as well as BLE 4.0.

On-board is a 3.3V regulator and a battery charging device that enables you to switch between using USB or battery power. The battery is automatically charged in the USB is plugged in. A status light shows if it is charging or fully charged. All ESP32 pins bar the flash pins are exposed and available for your use.

Buy it in the oddWires store…

Pins Used

IOT-Bus Pin Description
5 On-board LED


Pin 5 is the default SS for the vSPI interface and provided you are not using them at the same time it will work just fine for either purpose.


This is not an exhaustive list of libraries available for IoT-Bus but it is a useful list of some of the libraries we have used and especially those we have used for examples. The license for each of the libraries can be found on each library’s GitHub page.

Name Board Framework Description
webthing-arduino Io/Proteus Arduino Simple server for WiFi101, ESP8266, or ESP32 boards compliant with Mozilla’s proposed WoT API
ESPAsyncWebServer Io/Proteus Arduino Asynchronous HTTP and WebSocket Server for ESP32
ArduinoJson Io/Proteus Arduino C++ JSON library for IoT. Simple and efficient.
arduino-Lora LoRa Arduino Sandeep Mistry’s arduino-LoRa library
Arduino-CAN CAN Bus Arduino Sandeep Mistry’s Arduino-CAN library
Arduino-OBD2 CAN Bus Arduino Sandeep Mistry’s Arduino-OBD2 library requires Arduino-CAN
Adafruit_ILI9341 Display Arduino Adafruit’s ILI9341 library - use with Adafruit-GFX-Library.
Adafruit-GFX-Library Display Arduino Adafruit’s general purpose graphics library.
TFTeSPI Display Arduino Bodmer’s TFT library has been forked to setup defaults.
XPT2046_Touchscreen Display Arduino Fork of Paul Stoffgren’s XPT2046_Touchscreen library.
ESP32_TFT_library Display esp-idf loboris TFT library for ESP32
Adafruit_Motor_Shield_V2_Library Motor Arduino Adafruit V2 Motor Shield library
esp-mqtt Io/Proteus esp-idf Espressif MQTT library
esp-idf-lib IO/Proteus esp-idf UncleRus components for esp-idf framework. Mostly ports from esp-open-rtos

esp-idf-lib Components

Component Description License Thread safety
i2cdev I2C utilities MIT Yes
ds1307 Driver for DS1307 RTC module BSD Yes
ds3231 Driver for DS3231 high precision RTC module MIT Yes
hmc5883l Driver for HMC5883L 3-axis digital compass BSD Yes
onewire Bit-banging one wire driver MIT* No
ds18x20 Driver for DS18B20/DS18S20 families of one-wire temperature sensor ICs BSD No
dht Driver for DHT11/DHT22 temperature and humidity sensors BSD No
bmp180 Driver for BMP180 digital pressure sensor MIT Yes
bmp280 Driver for BMP280/BME280 digital pressure sensor MIT Yes
bh1750 Driver for BH1750 light sensor BSD Yes
ultrasonic Driver for ultrasonic range meters, e.g. HC-SR04, HY-SRF05 BSD No
pcf8574 Driver for PCF8574 remote 8-bit I/O expander for I2C-bus MIT Yes
hd44780 Universal driver for HD44780 LCD display BSD No
pca9685 Driver for 16-channel, 12-bit PWM PCA9685 BSD Yes
ms5611 Driver for barometic pressure sensor MS5611-01BA03 BSD Yes
ads111x Driver for ADS1113/ADS1114/ADS1115 I2C ADC BSD Yes
pcf8591 Driver for 8-bit ADC and an 8-bit DAC PCF8591 BSD Yes
tsl2561 Driver for light-to-digital converter TSL2561 BSD Yes
max7219 Driver for 8-Digit LED display drivers, MAX7219/MAX7221 BSD Yes
mcp23017 Driver for 16-bit I2C GPIO expander BSD Yes
tda74xx Driver for TDA7439/TDA7439DS/TDA7440D audio-processors MIT Yes


IoT-Bus Io Schematic


Name Description
Espressif32 Espressif Systems is a privately held fabless semiconductor company. They provide wireless communications and Wi-Fi chips which are widely used in mobile devices and the Internet of Things applications.


Name Description
Arduino Arduino Wiring-based Framework allows writing cross-platform software to control devices attached to a wide range of Arduino boards to create all kinds of creative coding, interactive objects, spaces or physical experiences.
ESP-IDF Espressif IoT Development Framework. Official development framework for ESP32.