Updated: Jun 23
So what is the big deal about launch controllers? Why should I spend money on one?
Rocket motor igniters use DC (direct current) of 3, 6, or 12 volts DC. A simple Estes controller is driven by a pair of 1.5v batteries for 3 volts. The cord on one of these is limited to ~15 feet, because when you run current through a wire, there is a limit to how far you can go. The voltage drops along the length of the wire due to resistance. At 12 volts the run can be longer and you will still get enough current to set off the ignitor. However, we are not talking about 100 feet, much less 300. Another option would be to use higher voltage. With a 48v power source you could get enough power to a remote pad. But now you are carrying four 12v batteries and connecting them in series. This is not very practical.
In order to get the power you need to ignite a rocket, you need the power supply (battery) close to where the rockets are. This is where launch controllers enter the story.
Relays have been in common use for a very long time. Before we invented the transistor, relays were used to control a large current by applying a very small current to an internal electromagnet, which pulls a lever to close the circuit and provide power where it is needed. Relays are widely used today. They are cheap, durable, and work fine with a wide range of voltage and temperature conditions. There are a lot of them in your automobile, even if it is computer controlled.
Our five channel controllers have six relays like the one shown above. They are located in the controller housing where the power pack is connected. Five relays select the pads to supply either continuity test current, or launch current. The Arm relay toggles between continuity and launch. The maximum length of wire between the power pack and rocket is 48 ft (HPR-V), and at 12v that is enough current to light that motor. The fact that your launch console is 300 feet away does not matter. The controller relays use only 28ma (milliamps) of current to operate.
The console operates the relays. It provides switches for these operations, and a local piezo beeper to check your hook up from a distance. There is an identical piezo beeper in the controller to sound when you test continuity from the pad. These beepers will only allow 20ma of current to pass through them, so they cannot set off the igniter.
We use high quality electrical components to build our controllers. All electrical connections are soldered or spade connectors. We build them to last for decades. You will go through quite a few batteries before you decide it is time to replace one of these controllers. In fact you might go through raising quite a few rocketeers to adulthood before you need to replace our controller.
They are simple electro mechanical systems. There are no voltage controllers or microprocessors in the mix. For IMPLS Launch, those may come into play for very large or very remote controller systems. For most clubs a simple electromechanical system is just right. We provide a 90 day warranty for product and workmanship on all of our controllers and pads. If you have any question or issue with our products you may contact us by email or phone for immediate attention. We love rocketry and we want to share the joys of flying with clean, reliable control systems.