You can find RF Transmitters & recievers here
Transmitter
https://www.electro-tech-online.com/custompdfs/2003/06/175khzx.pdf
Reciever
https://www.electro-tech-online.com/custompdfs/2003/06/175krvr.pdf
If you want to set off multiple fireworks, then you have to set up multiple frequencies by adjusting the number of turns in the coils.
This can be a game of trial and error, since the exact size of the core, and wire may differ from the one they used to construct it.
I'm also not sure of the distance this one transmits, sorry, I haven't used this one.
And in order to get the reciever to light something.
You'd have to modify this, so both the positive and negative hook up to seperate connectors.
I don't have a schematic so I'll just have to hope ASCII doesn't fail me.
-9V To ignitors +9V To ignitors
| | | | | | | | | | | | | | | | | | | |
----------------- -----------------
| |
-9V From Reciever +9V From Reciever
Okay, now the bottom of the diagram will represent the positive and negative wires going from the reciever, then they connect to 10 pins or copper surrounded holes where you can solder on 10 insulated wires (22ga) these would have one open end, and a small alligator clip on the other.
Now match the wires up, you don't really have to, but it's easier for figuring out what the hell's gonna happen here.
Take one positive and one negative alligator clip from each side and hook them up to the ignitors (if you're using your own, that's cool, I just prefer estes since they never fail) make sure they do not touch, and then attatch to the fireworks, if you want you can make your own gunpowder/epoxy charge on the firework so that it will definately light the fuse.
now when a signal hits, 9V will travel down these and through the ignitors setting them off until no closed connections are left.
However in order to make sure these baby's don't yank the reciever with them, have the reciever mounted to something around 10 Lbs, and when you put the ignitors in the alligator clips, make sure they are only holding the tips of each ignitor, because under normal circumstances, the ignitor will fall off, however some have been known to hang on and take your stuff for a ride several hundred feet in the air if you're not careful.