RocketSmith
Electronic Projects for the Rocket Enthusiast

PROJECTS

Launch Control Systems

          Basic Panel Control - Single Pad

Basic FET Circuit-

This circuit is designed to support an independently controlled arming relay and full control monitoring.  By using a resistor ladder network, the single monitoring point provides all of the information needed to allow for complete status monitoring of the circuit.  If the monitor voltage is about 4V then the circuit is armed with good continuity, if the voltage is about 2V then the circuit is safe with good continuity, if the voltage is about 1v then the circuit has no continuity, if the voltage is 0V then the circuit has a short in the FET and should not be used.  Control software in the supporting microcontroller provides indication control for status monitoring.  There is a 3.3 ohm series resistor in the circuit to current limit the draw through the FET to about 3.5 amps max to protect the FET and PCB from short circuit in the igniter.  Note: This monitor is no substitute for independent checking of the circuit prior to use, e.g. spark check prior to igniter hook-up.  Common-sense safe practices should always be used.

Microcontroller Circuit-

The microcontroller monitors the state of the control panel inputs and the FET status to provide status indication and launch control.  It is designed to provide status in the form of three LEDs and an auxiliary output.  The three LEDs provide power on indication, continuity/fault indication and armed indication.  The auxiliary output is driven by the arm logic to provide the ability to control a strobe or buzzer if desired.

Control Panel Circuit-

The control panel provides the switches and LED indicator for launch control and continuity from a remote location.  The interface is through a standard RJ11 phone connector and cable.  Typical cable length is about 25 feet, however, the system can be used with a cable up to 100 feet in length.  The system will operate with longer cables, however, the user cannot clearly see the indicator lights on the control head from a distance farther than 100 feet.

Control Head Layout and Design-

                Front View                                 Rear View

Control Panel Layout and Design-

                    top View

Completed Setup-

Control Head

Control Panel

setup

Software Design-

Printed Circuit Board Design-

Case Construction-

Parts List-