How to do connectionless UDP broadcast using Wi-Fi? I'm hoping to broadcast UDP packets using the Wi-Fi antenna to everyone else (running the same application) in range. I'd like to do this without having to establish a connection. Is this possible?

I'm able to establish a P2P Wi-Fi connection and then send a multicast message, but that's not quite what I want.
Yes, it's possible, but you must learn IEE802.11 Datagram very well. There are two ways, the first provides two-way data exchange, the second only broadcasts to receivers:


use the beacon frame and Probe request/response frame to send data from AP to clients without connection


Broadcasting Information in Variably Dense Environment Using Connectionless Data Exchange (CoLDE)

use the length field in the data frame to broadcast only. You should develop a communication protocol with the encoded length. The receiver should:


enter Promiscuous Model
switch channels
Provide a 100ms timer interrupt at least.