- EasyMotor needs to be rigidly attached in the airframe, and the
- long axis of the circuit board needs to be aligned with the axis
- of flight. By default, the round beeper on the board should be
- “up” towards the nose cone, and the screw terminal strips should
- be “down” towards the fins and motor nozzle end of the rocket.
+ [WARNING]
+ Firmware versions prior to 1.9.13 used acceleration to detect
+ launch. Starting with 1.9.13, the firmware switched to using
+ pressure to trigger recording. Altus Metrum strongly recommends
+ upgrading all EasyMotor boards to current firmware, the
+ behavior of which is described here.
+
+ EasyMotor needs to be rigidly attached in the airframe, in any
+ convenient orientation.
+
+ === Trigger to Start Recording
+
+ Starting with firmware version 1.9.13, a pressure sensor must
+ be attached, and pressure change is used to initiate and conclude
+ data recording. Pressure and 3 axes of acceleration are recorded
+ for later analysis.
+
+ EasyMotor looks for a 50 psi rise in pressure from ambient to
+ start recording. Recording stops when the pressure drops
+ below 50 psi and shows variation of less than 30 psi for at
+ least 10 seconds. These conditions are intended to capture all
+ actual burn data including anomalies such as "chuffs".
projects / fw / altos / blobdiff