Tuesday, October 29, 2013

ServoChron Firmware and Documentation Updates

U.S. Water Rockets has released the newest ServoChron: the MSP430 LaunchPad based dual time delayed Servo controller for rocketry and other applications.

The newly enhanced ServoChron functions as a dual programmable delay timer that can move up to 2 servomotors between defined positions after a programmed time delay has elapsed from the moment a trigger input changes state. This functionality is intended for use with model rockets to deploy one or two parachutes at programmed intervals after launch has been detected. However, the device can be used in any situation where a servo needs to change position when some event triggers an input.

New in this version is an immediate trigger override input which can be used to read an apogee detect circuit (like a digital output from an external altimeter) and deploy the parachute immediately. Combine this feature with the built in timer feature and you have an apogee triggered servo deploy system with a timer backup.

The ServoChron will run on any MSP430 LaunchPad, including the early MSP430G2231 based versions. A custom software UART was developed for this variant which allows it to send the same diagnostic messages across the MSP430 Application UART backchannel while still driving the servos, just like the MSP430G2553 based Launchpad version.

A key feature of the ServoChron is the clever user interface, which allows the time delay and the servo positions to be configured without any external switches, and saves the configuration in the nonvolatile memory of the MSP430.

The software also includes an automatic polarity detect on the trigger input, so it will work with Normally Open or Normally Closed trigger circuits.

The ServoChron is demonstrated in a real water rocket launch and parachute recovery in the following video:

Instructions for making a simple servo operated Parachute deployment system are shown in this tutorial video: http://www.youtube.com/watch?v=vqTKXXpD9IU

The configuration of the ServoChron is demonstrated in the following video:

Along with the newly improved firmware, we have also reworked all of the instructions and manuals to make them easier to navigate. The new instructions for assembly, programming, and operation of the ServoChron are available at the  following link: http://www.uswaterrockets.com/documents/ServoChron/manual.htm