So I had the Trigger database write code all working with variance triggers for the Magnetometer, Accelerometer and Gyroscope. However, I noticed the datetime for writing was only accurate to 1 second. Triggers are done in ms not sec. It took me a bit to figure out how to format the strftime in SQLite3 properly (compounded by another error when I changed how the DB is checked).
Long story short, it now records trigger events down to 3 decimal points of a second. This will be perfect, since I usually do things no lower than 100ms.
I have made both the Trigger DB AND the Interval DB into continually running programs instead of one off runs, so it doesn’t have to load up all the code every time it writes to the database. This can have a big impact on how long it takes to get the sensor readings, which is important for the time sensitive Trigger code.
I was thinking of getting the datestamp for writing into the database, after the sensor readings are returned from the hardware sensor, but then I have to use python to find and convert the timezone off the Sensor itself into the nice generic UTC 0… But i’m not sure how to Dynamically get the timezone off the System to do the conversion (Not to mention, that alone may add more delay between getting the readings and the timestamp). So i’m letting SQLite3 itself insert the time when it writes to the DB, as it always writes in UTC 0 if you don’t specify.
This isn’t super accurate, since it has to go through a few functions before it can write, but it is a relatively small difference for when the DB is written vs when it got the sensor readings. I tested the time difference by printing the system time to the screen, just after each Trigger reading, and comparing it to what it is in the database. It seems like the accuracy is within 200ms on a Raspberry Pi 3B+.
In other news, I found out how to disable Resizing the window using GUIZero and created prompts for when actions are complete, such as downloading Databases and sending commands to the sensors. This especially helps when the network is not so great and you get longer wait times and or network timeouts.
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