openrocketryinitiative / motors

Wi-Fi enabled thrust-test stand for rocket motors.

Smart Thrust Test Stand

Recording thrust data

numpy, scipy, matplotlib, pyserial, datetime, and adafruit-ads1x15 are required for logging. All of these can be installed with pip.

All thrust data is recorded to the thrust-tests/ folder.

For easy use, add the bakery bin to your path in your .profile: export PATH="$PATH:/path/to/bakery/explosive-bakery/bin"

You now have the following commands:

• init-test [-h] (-n NAME | -j JSON_FILE) The script initializes a thrust test, allowing to set rocket parameters. Exactly one of n or -j is required. -n specifies the name of the test (i.e. batch_30a). With -n, a new JSON file will be created. -j points to an existing JSON file, which will be loaded then overwritten with the new input parameters.

• start-test [-h] (-j JSON_FILE | -n NAME) [-c] The script begins a thrust test, logging data until told to stop with a keyboard interrupt. The data is saved to a JSON file for later analysis. Exactly one of -n or -j is required. -n specifies the name of the test (i.e. batch_30a). If the test already exists in the input date folder, the existing JSON will be used. If the test does not exist, a new one will be initiated. The j parameter points to an existing JSON file to use for the test. -c will allow you to set options for the launch, such as motor length, fuel type, etc.

• analyze [-h] -j JSON_FILE [-r] The script computes standard properties of a motor burn (impulse, average thrust, burn time, etc.) -j is a required argument. It points to the JSON file to analyze. -r resets the times between which the motor was burning.