ESP WiFi Sensor Project

ESP32 Introduction

The 2.4 GHz Wi-Fi and Bluetooth combo chip" is the name of its ESP32 Development Board, released in September 2016. It already lists two of the main features: The less than 6 cm board comes with an integrated Wi-Fi module and Bluetooth 4.2 -- for less than 15 € (link In this post, we give an introduction to the ESP32, comparing it to the Arduino and setting up the development environment to the extent that you can perform a Wi-Fi scan.


Caption: Proud 34 differently assignable pins are placed outwards. At the top right of the picture is the Wi-Fi antenna attached to the board.



The ESP32 has a variety of features that are unusual in the price class: it has a built-in Wi-Fi module that can be used via the available code libraries with a few lines of code to retrieve data from a web server. A hobbyist from the area south of Stuttgart even managed to receive data from the ESP32 Wi-Fi module at a distance of 10 km (!) (link For example, the onboard Bluetooth module can be used to transfer data to smartphones or other Bluetooth-enabled devices. Furthermore, the module has a 2-core 32 bit processor that operates at a clock frequency of 160 or 240 MHz. compared to the Arduino (16 MHz) a huge advance (exact benchmarks The amount of memory (SRAM) is 520 KiB. Also worth mentioning are the 16 PWM channels, a temperature sensor, four SPI, three UART and two I2C interfaces, two digital-to-analog converters and much more. 


Comparison with a microcontroller, compatible with the Arduino Uno



Microcontroller, compatible with the Arduino Uno (ATmega 328P)



Processor (CPU)

240 MHz dual core Tensilica LX6

16 MHz single core

Memory (SRAM)

520 KiB

1 KiB

Pins (GPIO)

34 different pins

20 Pins (14 digital, 6 analog in)


3.3 V

5 V


Wi-Fi, Bluetooth 4.2

nothing like it

PWM Pins

up to 16 outputs

6 outputs

Digital to Analog




under 15 €


Arduino compatible for less than 8 € (



The ESP32 module can be programmed in three different ways: (1) With the Espressif IoT Development Framework (ESP-IDF in very machine-taken C++. Eclipse, for example, is a development environment (IDE). (2) Also in the Arduino IDE, with the usual functions (digitalWrite, attachInterrupt, ...). We will continue to pursue this possibility here, as it is most suitable for beginners. (3) With the Programming Language Lua (


The code associated with Option 2 (programming with the Arduino IDE) can be found in a repository of Espressif on GitHub ( There you will also find detailed, illustrated installation instructions for Windows, Mac and Linux ( If you do not see a new COM port in the Arduino IDE and Windows Device Manager after performing each step, install the USB to UART Bridge drivers. ( In the Arduino development environment, new boards are available, which you can select from the menu under Tools > Board > ESP32 Arduino. 



Wi-Fi Scan

The "Hello World!" of an ESP32 is not the flashing of an LED: we start by listing the Wlan networks within range; with signal strength in dBm! ( To do this, select the sketch WiFiScan sample, which you can find in the menu under File > Examples > Examples for ESP32 Dev Module > WiFi > WifiScan and upload it to the ESP32 Dev Module connected via Micro USB. To see the output, you need to increase the baud rate in the Serial Monitor to 115200.


1: DJ_Simsso (-31)*
2: TP-LINK (-66)*
3: YouShallNotPass (-67)*
4: FortKnox (-85)*
5: TP LINK_5246 (-88)*
6: KA-WLAN (-92) 
7: TOPSECRET (-93)*


In our content-related posts we show how to host a local website with the ESP32 and display sensor data on it. Here you can find the project on an ESP8266 module.


Finally, some links that help you get into the ESP32 world or are a good reference.


Community at





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