Brushed speed controller questions

[stegla]

Hi Guys,
I'm trying to develop a small freeflight timer/controller using a pic to vary the mark/space drive to a fet that powers a motor.

What is a good frequency to drive a brushed ferrite motor using the above?

How do you make a motor buzz without it actually spinning? I would like a series of bleeps prior the the motor springing to life.

What is the standard low voltage cut-off for a lipo cell?

Steve

[pmackenzie]

1) 2K-5K should be fine.
2) Just send it low duty cycle tones to make it "beep". Adjust the duty cycle to get it to make enough sound, but not actually run.
3) Under load, 3 volts. 3.2 is a bit safer. It should recover to at least 3.7.

Pat MacKenzie

[stegla]

Thanks Pat for the speedy reply!!!

Steve