The protocol was developed by Espressif Systems. It is similar to the 2.4 GHz wireless connectivity deployed in wireless keyboards and mouses.
Why use ESP-Now?
No need of a Wi-Fi network made by a router
Low-power consumption protocol
Prior pairing of devices required
After initial pairing, the connection is incessant
Peer-to-peer connection, without the constraint of handshake
Supports a maximum of 20 peers
Program Flow: Master
Program Flow: Slave
Note: Master and slave have been defined to easily understand the setup. Based on the ESP-Now API, there is no concept of master and slave. Any device can act as a master or a slave.
Let us now see a simple application of ESP Now. Make the circuit connections as shown below. Download the code from the link(s) mentioned below. Upload the code for master and slave devices to their respective ESPs. Here, the data from the digital IR sensor is being sent to the slave from the master. A global variable is being used to set the GPIO pin to high or low, based on the data received from the master. Subsequently, the LED and buzzer connected to the GPIO are set accordingly.