Error when performing the propeller test on Crazyflie 2.1+

[RPS98]

I have similar problem as https://github.com/orgs/bitcraze/discussions/1763

I just bought 4 Crazyflie 2.1+ (https://store.bitcraze.io/collections/platforms/products/crazyflie-2-1-plus).

The console shows this at startup (there doesn’t seem to be any error):

SYS: ----------------------------
SYS: Crazyflie 2.1 is up and running!
SYS: Build 0:b046745801fc (2024.10.2) CLEAN
SYS: I am 0x38303638343351080048002E and I have 1024KB of flash!
CFGBLK: v1, verification [OK]
DECK_CORE: 0 deck(s) found
IMU: BMI088: Using I2C interface.
IMU: BMI088 Gyro connection [OK].
IMU: BMI088 Accel connection [OK]
IMU: BMP388 I2C connection [OK]
ESTIMATOR: Using Complementary (1) estimator
CONTROLLER: Using PID (1) controller
MTR-DRV: Using brushed motor driver
SYS: About to run tests in system.c.
SYS: NRF51 version: 2024.10 (CF21)
EEPROM: I2C connection [OK].
STORAGE: Storage check [OK].
IMU: BMI088 gyro self-test [OK]
SYS: Self test passed!
STAB: Wait for sensor calibration...
SYS: Free heap: 17936 bytes
STAB: Starting stabilizer loop
SUP: Can not fly
SUP: Ready to fly

However, when I run the propeller test, after testing motor 1 and motor 2, the drone reboots.
Additionally, motor 1 has a very high variance.
This happens with all four drones I purchased.

HEALTH: Acc noise floor variance X+Y:0.004299, (Z:0.002456)
HEALTH: Motor M1 variance X+Y: 14.72 (Z:56.06), voltage sag:0.38
HEALTH: Motor M2 variance X+Y: 3.12 (Z:8.28), voltage sag:0.38
SYS: ----------------------------
SYS: Crazyflie 2.1 is up and running!
SYS: Build 0:b046745801fc (2024.10.2) CLEAN
SYS: I am 0x38303638343351080048002E and I have 1024KB of flash!
CFGBLK: v1, verification [OK]
DECK_CORE: 0 deck(s) found
IMU: BMI088: Using I2C interface.
IMU: BMI088 Gyro connection [OK].
IMU: BMI088 Accel connection [OK]
IMU: BMP388 I2C connection [OK]
ESTIMATOR: Using Complementary (1) estimator
CONTROLLER: Using PID (1) controller
MTR-DRV: Using brushed motor driver
SYS: About to run tests in system.c.
SYS: NRF51 version: 2024.10 (CF21)
EEPROM: I2C connection [OK].
STORAGE: Storage check [OK].
IMU: BMI088 gyro self-test [OK]
SYS: The system resumed after a failed assert [WARNING]
SYS: Assert failed at ../src/modules/src/stabilizer.c:276
SYS: cfAssertNormalStart [FAIL]

I have a previously purchased Crazyflie 2.1. When I run the propeller test, it works correctly:

HEALTH: Acc noise floor variance X+Y:0.004057, (Z:0.002113)
HEALTH: Motor M1 variance X+Y: 2.92 (Z:8.50), voltage sag:0.51
HEALTH: Motor M2 variance X+Y: 5.61 (Z:18.02), voltage sag:0.52
HEALTH: Motor M3 variance X+Y: 0.93 (Z:1.57), voltage sag:0.48
HEALTH: Motor M4 variance X+Y: 1.49 (Z:2.48), voltage sag:0.54
HEALTH: Propeller test on M1 [FAIL]. low: 0.0, high: 2.50, measured: 2.92
HEALTH: Propeller test on M2 [FAIL]. low: 0.0, high: 2.50, measured: 5.61
STAB: WARNING: stabilizer loop rate is off (307)

I also tried mounting the motors from the Cf 2.1 onto the Cf 2.1+, but it still doesn't work.
When I downgrade the firmware from Cf 2024.10.2 (the latest) to a previous version, 2024.2, the propeller test works correctly.

Any help?

[gemenerik]

Can you try again with the latest firmware (2025.02)? The fix mentioned in the linked issue is part of this release.

[carmendrpr]

With the latest firmware I can run the propeller test correctly with the four motors.
However, the four of them fail.
The console shows this:

HEALTH: Acc noise floor variance X+Y:0.003894, (Z:0.002891)
HEALTH: Motor M1 variance X+Y: 4.63 (Z:2.50), voltage sag:0.41
HEALTH: Motor M2 variance X+Y: 21.41 (Z:33.43), voltage sag:0.42
HEALTH: Motor M3 variance X+Y: 8.12 (Z:4.63), voltage sag:0.42
HEALTH: Motor M4 variance X+Y: 21.14 (Z:17.20), voltage sag:0.42
HEALTH: Propeller test on M1 [FAIL]. low: 0.0, high: 2.50, measured: 4.63
HEALTH: Propeller test on M2 [FAIL]. low: 0.0, high: 2.50, measured: 21.41
HEALTH: Propeller test on M3 [FAIL]. low: 0.0, high: 2.50, measured: 8.12
HEALTH: Propeller test on M4 [FAIL]. low: 0.0, high: 2.50, measured: 21.14
STAB: WARNING: stabilizer loop rate is off (432)

[tobbeanton]

The propellers on the 2.1+ is different and rotates at a higher RPM. The test levels are not tuned for this so unfortunately the fail threshold is not useful at the moment. They give you an indication of any propeller+motor that might be vibrating more then others.

[carmendrpr]

What would be the levels of testing they should have?

[tobbeanton]

Sorry we do not have a level yet and the old one is pretty experimental. If you experience degraded flight performance I would use the numbers to help with which motors/props to check. So in the case above I would check M2 and M4. During harder crashes the motor shaft can get bent so check for this as well.