User blog comment:Brandonlock1213/11/17/10/@comment-3224636-20101121230707

Is it possible that we could get by without the down-facing motor being controlled via PWM? If the ultrasonic sensor feeds us data fast enough and the software is doing simple digital pin switching based on what direction we need our blimp to go, it might be that the blimp flies just fine with the motor either on or off (on doesn't have to be full power either, just toss in a resistor if the motor is too fast). As I understand it, the only real advantage of PWM would be when we need to do efficient real-time speed control, but the blimp isn't going to sink or rise so fast that we'd need to calculate how fast that particular motor should be running to safely maintain a good distance off the ground. The only case I can think of is if the blimp were suddenly hit with something, dynamic speed control would allow us to turn the motor on extra quickly to regain position. In other words, for the vast majority of the time, there's no acceleration change of the bottom motor, so spending large amounts of time worrying about PWM right now seems overkill