ThustMaster - A Rocket Motor Dynamometer

A rocket motor dynamometer, or dyno, is a device used to measure the thrust force generated by a rocket motor. It typically consists of a test stand where the motor is mounted and a force sensor that captures the thrust produced during a motor burn. The data collected by the dyno is crucial for understanding the performance characteristics of the motor, such as its thrust curve, total impulse, and specific impulse. This information is essential for the design and safety analysis of rocket motors.

Equipment Setup

1. Ensure the Arduino board is powered off before connecting any sensors or actuators.
2. Connect the force sensor to the PIN_ADC_DT and PIN_ADC_SCK as defined in config.h.
3. Attach the pyrotechnic device to PIN_PYRO.
4. Connect the speaker (if used) to PIN_SPEAKER.
5. Insert an SD card into the SD card module and connect it to the PIN_CS.
6. Connect the LED to PIN_LED.
7. Attach a button to PIN_BTN for starting the test sequence.

Configuration

Before running the test, verify the following settings in config.h:

• COUNTDOWN_TIME is set to the desired countdown duration in seconds before the test starts.
• TEST_DURATION is the duration in seconds for which the test will run.
• PYRO_DURATION is the duration in milliseconds for which the pyrotechnic device will be active.
• DATA_FILENAME is set to the desired path and filename for the data log on the SD card.
• PROFILE_FILENAME is set to the desired path and filename for the profile data on the SD card.

Running the Test

1. Power on the Arduino board.
2. Press the button connected to PIN_BTN to initiate the countdown.
3. Observe the LED and listen for the tone from the speaker (if enabled) during the countdown. Move AWAY from the motor! I know you know this ;-)
4. The test will automatically start after the countdown, activating the pyrotechnic device and beginning data collection.
5. Force measurements will be taken and stored in memory until the TEST_DURATION is reached or the maximum number of measurements (maxMeasurements) is collected.
6. Upon test completion, the data will be written to the SD card with the filename specified in DATA_FILENAME, and the thrust profile data will be written to the file specified in PROFILE_FILENAME.
7. The LED and speaker (if enabled) will signal the end of the test sequence.

Data Retrieval

After the test has finished, remove the SD card from the module and insert it into a computer to retrieve the files dyno.csv and profile.txt containing the time and force measurements, and the thrust performance profile, respectively.

Safety Precautions

• Ensure that all connections are secure and that the equipment is in good working order before starting the test.
• Keep a safe distance from the pyrotechnic device when the test is running.
• Do not attempt to retrieve the SD card until the test has completely finished and the equipment is powered down.

Troubleshooting

If the test does not start or there are issues with data logging, check the serial monitor for debug messages if DEBUG is defined in config.h. Ensure that the SD card is properly formatted and not write-protected.

For further assistance, refer to the ThrustMaster.ino sketch comments and the logger.h file for debugging procedures.

Notes

• The speaker functionality is disabled by default. To enable it, define SPEAKER_ENABLE in config.h.
• The test procedure assumes that the initSDCard(), initHX711(), and other initialization functions are correctly implemented as per the ThrustMaster.ino sketch.
• The maximum number of measurements that can be stored is defined by maxMeasurements in the ThrustMaster.ino sketch.

Parts

TODO: link to parts on amazon

Example Build

TODO: upload circuit diagram