Connect 4 HC-12 transmitters to 1 HC-12 receiver
When a HC-12 is transmiting all other HC-12 in his range (using same frequency) are receiving. So if you want your transmiter to talk to one specific HC-12 then to an other and so on, you have to create a kind of &quot;message protocol&quot;.
Let's say you have an Arduino with a HC-12 and 4 buttons and want to turn on-off 4 lights, each connected to a HC-12. You can use a binary representation, so a byte, on which each bit as a meaning.
Bit 0 -&gt; at 1 -&gt; turn on the light at 0 turn off
Bit 1-2 -&gt; give the number of the HC-12
So 00000111 -&gt; message for HC12 number 4, tell it to turn on the light.
ALL HC-12 will receive the message. So each has to check the incoming byte to see if &quot;it's for me&quot; or nor.
If you want one HC-12 to receive from many HC-12, that's the same: the message must contain the &quot;id&quot; of &quot;who is sending&quot;.