How to Monitor Ultrasonic Distance With ESP8266 and AskSensors IoT Cloud

This instructable presents how to monitor the distance from an object using ultrasonic HC-SR04 sensor and ESP8266 node MCU connected to the AskSensors IoT cloud.

Step 1: Material We Need

We will need the following Hardware:

ESP8266 Node MCU
Ultrasonic HC-SR04 Sensor
Bread Board
Jumper wires
Micro USB cable

Step 2: Build Your Hardware

Connect the ultrasonic sensor to the ESP8266 node MCU:

HC-SR01 TRIG pin to ESP8266 D1 pin
HC-SR01 ECHO pin to ESP8266 D2 pin
HC-SR01 VCC pin to 5V (you can also try with 3.3V)
Ground to ground

Note:The ESP8266 GPIOs require 3V3 signals (not 5V tolerent). For quick hack, if you are using the HC-SR (5V version), we highly recommend to add a serial resistor between the HC-SR TRIG and ECHO pins and the ESP8266 pins. However, for production, a 3V3/5V level shifter is needed (check this page).

Otherwise, The ESP8266 is compatible with HC-SR 3V3 version and no level shifter is needed in this case.

Step 3: AskSensors Setup

Get a free account at https://asksensors.com/
Sign in and create a new Sensor.
Copy down your Sensor API KEY IN.

Step 4: Download the Code

Download the code from the AskSensors github Page.

Decompress it and fill the following informations:

const char* wifi_ssid = "....................";             // SSID
const char* wifi_password = "....................";         // WIFI 
const char* apiKeyIn = "..................";      // API KEY IN