I purchased a radio system a few years ago, the plan was to use it as a back up deployment system in a rocket.
My rockets outgrew the systems range before I even installed it in a rocket, so the system sat on a shelf waiting
for a new mission. I noticed is again the other day, and decided to put it to use as a remote, radio controlled
launch controller.
I'm not going to get into specific details, although I suspect anyone with an IQ over 85 could figure out how to
do it... I'm also not going to give details of the transmitter, you'll have to use your imagination there.
I have to admit, this wasn't a high priority of mine. A lot of people complain about stringing out wire from the
launch controller to the pad, I really don't mind it that much, but it would be handy to only run one extension
cord from the pad to the radio controlled launch box.

Here is the basic system ready to go.
I have three lead acid AGM batteries I use to power a variety of items in the field, so I ran a power lead into the launch box using my standard 4 pin XLR jack and plug. The 12 volt battery powers the radio receiver and servo via a LM317 voltage regulator. Full 12 volt power passes out to a standard extension cord end by way of a 10 amp relay.

Here it is from another view.
The wires going to the top of the case are for a momentary switch to test continuity. Rather than using a light to indicate continuity, I'm using a small piezo buzzer inside the case.

Here's the system closed up and the battery in its case.
In use, I think I'll set up a 100' wire from the launch pad to the radio controller as an added measure of safety. I'll leave the cord unplugged to the pad until the system is powered up and the output tested to make sure it's not live. Then the actual cord to the pad will be plugged in, I'll test continuity, then move to the safe site to initiate ignition. I'm not sure of the range, I set up the system one night and paced off 450' and it was still working fine. I'm sure line of sight is in the 1000' range.