Compute on the ESP32. I do tilt alarms on irrigation pivots this way.
The drops: a device profile by default allows 10 telemetry messages per second and 200 data points per second. You send 50 messages and 450 points a second, so most of it is acknowledged and dropped, and a device that keeps breaking its limit gets its session closed. That’s the rate_limit in the log. See MQTT for the table.
Angles, for roberts.r too: roll is rotation around the pallet’s long axis, pitch around the short axis, yaw is the compass heading. From the accelerometer alone, when the pallet is still:
float roll = atan2(ay, az) * 180 / PI;
float pitch = atan2(-ax, sqrt(ay * ay + az * az)) * 180 / PI;In a moving truck the accelerometer also sees braking and bumps, so blend it with the gyro (complementary filter, about 98 % gyro, 2 % accel) or use a Madgwick filter library, which also uses the magnetometer for yaw.
Then send what you need, not the raw stream: once every 10 s the current roll/pitch, plus an immediate message when the tilt passes, say, 30°:
{"roll": 2.1, "pitch": -0.8, "tilt_max": 3.4}tilt_max is the biggest tilt seen since the last message, so a short tip between messages is not lost. An alarm rule on tilt_max > 30 is then all you need.