Rocketry Photography - Camera Controller

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I use to activate the on board movie camera using the Missile Works Wireless Remote Control (WRC). It would trigger an SCR on the rocket and the camera would start running about three seconds remaining on the countdown so I could capture motor ignition. The SCR would “lock” on the camera to ensure it would run until it ran out of film. It worked well except for when the Launch Control Officer had the switches in the wrong position! The film lasts only about 30 seconds so by the time he figured out what was wrong, I had burned up all my film on the pad.

I needed a controller to use the input from the launcher, start the on board camera, wait some amount of time and then launch the rocket. This would also let me add multiple cameras on the pad, start them at different times, and run them for specific amount of time to minimize the wasted film.

I find myself adding more and more ground cameras to control and although there may be enough connections for the cameras, I was concerned about the start up current by starting multiple cameras at the same time. I needed a more versatile timer to start and stop multiple loads at different times. Even if I staggered the on times by 1/4 second, it would make a huge difference in the voltage drop across the battery. The number of loads was also increasing because of adding the pitching mechanism. The releasing mechanism used a solenoid that also had to be activated.

My controller has increased in size but is an extremely versatile device. Housed in a cabinet style box, it has the timers on top, batteries on he bottom and is portable to take to the field.

There are ten timers that control various relay outputs. Each timer can be connected to the various outputs via a jumper. Eight of the timers are activated from the signal from the launch controller and two are started from the activation switch as the rocket lifts off.

Underneath the panel that houses the timers is the wiring complex to feed the output connectors. There are two battery sources. Most of the timers are connected to a 30 VDC pack but a few are connected to a 12 VDC pack for other loads.

This picture shows the bottom of the cabinet that houses the battery packs. The 30 VDC pack is actually made up from 35 AHr sealed lead acid battery packs. Although the cameras do not need that capacity, there is some fairly high start up currents.

Above the battery packs is a reel that can hold up to 1000 feet of wire for a remote camera. The reel is motorized to retract the wire and wind it up on the reel after a long weekend of flying.

Above the reel is a shelf that can be used to store various jumpers that are used, tools needed at the launch pad, etc.

The cabinet was built with wheels on the back and handles to tip the unit for easy transport around the field. The entire weight of the camera controller is about 250 pounds.

Here is a shot of the back showing the handles. The frame was constructed from 8020 aluminum channel. In he back is the on-off switch and a bracket to mount one of the junction boxes for the umbilical.

The umbilical transfers the power to the various loads on the launch pad. There are three junction boxes, one for the camera controller, one for the base of the launch pad, and one for the upper tower. By simply plugging in a jumper from the timer output and connecting a camera to the same connector at the opposite end I can select which timer controls each camera.

Here is a close up shot of one of the junction boxes. The cable actually has sixty 16 AWG wires. Many were doubled up for an effective 12 AWG wire. These are used for the high current cameras. Some connections were left as single wires for the lighter loads.

This is one example of a non-camera load. This simple relay box is used to trigger one a still camera. It has a voltage regulator to ensure the relay has the correct voltage despite the length and loss of the voltage drop of the line.

This is the remote power box used when a camera is placed very far away. The losses in extremely long lines would not allow a camera to be powered up. So the output of the timers is used as a signal to drive a relay in this box to power the camera.

The inside lid of the remote power box. Like the small relay box, it has voltage regulators on the relays to ensure the relays have the proper voltage despite the losses in the line. High current automobile relays were used.

The remote power box also had to provide power for the camera. Five 6 VDC batteries were used but since it only has to power one camera, smaller capacity batteries are used.

Although the camera controller is almost entirely triggered by the LCO's launch controller, I can use a Missile Works WRC to trigger the sequence.

This is a shot on the field. Jumpers are used to connect the output from the timers to the junction box mounted on he back of the controller. The umbilical is ran to the pad for connecting to the cameras.