Camera Controller

Can I connect the circuit to a 9V battery?

Yes. You can use the Shutter/External Power connector to power the controller with any power source from 6V-15V. See the User Manual for more information.

Everything works but the serial port.

This is most likely a cabling problem. Try swapping the Rx and Tx lines on the cable. Also, make sure you have a connection between the timer's GND and the GND (pin 5) of the other devices serial port.

What if I don't have a computer or Palm Pilot to program the timer? Do I still need to add the serial port?

You can still use it. You can program the timer (except for the Shutter Speed setting) using User Mode. If you never plan to use the serial port programming features you can leave off the parts from the design and the circuit will still behave correctly. It's a good idea, however, to leave the 100K resistor in place. This keeps the pin from floating and confusing the PIC with garbage data.

My controller acts flaky. I program it for a specific launch detect but it seems to change randomly. What's going on?

Prior to version 1.60 of the firmware all 8pin parts had a bug that sometimes overwrote the Launch Detect with an internal status word. This has been fixed and a free replacement for your 8pin chip is available. Please contact me for details.

What if I don't want to modify my camera what can I do?

You can use the latest software that supports servo control connected to a small RC servo and a cam lever to trip the shutter mechanically. The Servo Mode flight parameter controls the amount of "throw" in the servo arm when the shutter is tripped. Larger values result in more throw.

The Camera Controller says it took 24 pictures but my camera only says 22. What's happening?

The controller is probably using a Picture Interval which is too short so your camera is dropping an occasional picture. If your camera batteries are weak or you trimmed the timing without film in the camera the camera may be taking longer to recover between shots than you think. Remember the camera may need time to focus, take the picture and wind the film. Also the G forces of boost may affect the motors in the camera. Try increasing the Picture Interval a couple of tenths of a second.

I placed a new battery in the controller and tried to power it up. It won't power up but the battery gets warm. What's going on?

The battery is probably shorting out through it's own case. This can happen if the battery is scratched. Assuming the battery hasn't been drained from being shorted you can correct this by wrapping the battery with tape.

Can I do anything else with the Camera Controller?

Sure. For example using the servo drive capability the controller can be used for non-pyro deployment. See the July/August 2005 issue of Sport Rocketry. There is an excellent article on how to use a servo to trip a spring-loaded deployment mechanism. The article describes using a standard timer and a custom circuit to provide the delay and servo drive functions but the AYUCR Camera Controller can handle this on its own. The controller could be configured to take a single "picture" with a Launch Delay corresponding to the time to apogee. The Servo Mode should be a high enough value so that the servo arm reliably trips the catch.

Another use might be a servo-based deployment release mechanism. Most release systems use a small pyro charge to release a toggle attached to the recovery system to deploy the main chute. You would need to design a way to capture the toggle in such a way, perhaps using a pin through the toggle, and release the pin mechanically. You would need to ground test carefully to ensure that the servo can reliably release the toggle under load.

While it is possible to use the Camera Controller as a deployment timer I do not recommend it. The Camera Controller can not check continuity which is important to ensure reliable deployment.

What good are the serial port command for arming and initiating launch

The Arm, Disarm and Launch commands are useful if you'd like to interface the controller with other flight avionics. They were added primarily for remote control but may have other uses. For example if you'd like to use the controller to take flight video using the movie mode on your digital camera you may run into a problem. The controller won't start the video until launch is detected and with the shutter lag on some cameras it might be a second or two before the video starts rolling. You can miss a significant portion of the boost. Using a remote control arming circuit interfaced to the Camera Controller serial port one could send a signal to initial launch during the countdown and not miss any of the flight. The gswitch will still start the video as a backup.