On some teams’ robots, I’ve noticed that their TalonFX-based motors have a higher-pitch stall chirp, which effectively makes their robot quieter when they intentionally stall the motor (a use case would be applying a holding power to a mechanism). How do these teams achieve this? I haven’t been able to find documentation on it, other than playing CHIRP files when the robot is disabled and not moving, which is not what I intend to do.
This is a built in feature to the talonfx that can’t be disabled.
Im a little confused here, do you want to play sound through the motor when its stalling?
you can only play sound through the motor when its not moving (and i believe now when its disabled) and the chirping sound you hear when you stall a motor cant be disabled.
I am referring to the higher-pitch stall chirp that certain teams have applied to their motors. One of the notable teams that have done this, last season and this season, is 6328. Rather than the medium-frequency that comes from these motors out of the box, these teams have a much higher-frequency alerting them that the motor is stalling. Is this a setting in Phoenix Tuner? Is there a physical modification to change the pitch of the motor’s stall chirp?
Do you have a clip of the audio?
The loudness is based on how hard it’s being stalled. Below a certain point, it just doesn’t play, and the volume increases as the stall force increases.
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Here is a video from 6328 with their stall chirp: https://youtube.com/shorts/R1YhtPT7aAI?si=bcS9wgjnIPFR3va8
I feel like it just sounds that way because of the recording phone’s microphone. The only thing I know that changes the loudness (not the pitch) of the stall chirp is the current of the stalling motor.
I have heard this exact stall chirp from another team in person. It doesn’t seem to be a microphone trick, so if not then what causes it?
No basis for this hypothesis, but have you noticed if it is a particular motor that makes the tone you want? The housing has changed between Falcon, Kraken x60 and Kraken x44. This could also be a firmware version thing. I remember some sound settings being different in Phoenix 5.
One thing to note is that none of the motors in that clip are in a “pure” stall state pulling constant current. There are several motors that may be contributing to the noise (I don’t recall the exact setup when that clip was recorded), all of which are running either PID controllers or otherwise ramping the applied current based on the state and movement of the robot. You may be perceiving the sound differently because of the combination of motors stalling at different levels over time.
I can confirm that we haven’t done anything to customize the sound or explicitly play a different tone (we have much better ways of communicating the state of the robot to the driver).
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The motors definitely chirp different if you are in normal code versus FOC control (the premium mode).
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This explanation would also make sense, since all of the motors that might be stalling in the linked video are running in pure torque-current control modes (not even just the normal hybrid FOC modes).
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This makes sense, especially if the chirp is built into the hardware of the motor. Thank you!