Reacharound
New Member
Hi. I'm new at this and looking for advice or pointers to resources.
I'd like to drive a 3V DC motor in response to a flex sensor (its just a variable resistor/voltage divider set-up, but it won't handle very much current). Bend the arm, more power to the motor, robot rolls forward faster. This is just an analog voltage divider thing; I don't need digitizing.
I know the flex sensor can't handle enough current to drive a motor, so I need some sort of separate amplifier. I know how voltage dividers work. Should I use an op-amp, or do you not drive motors with an op-amp? Should I use a PWM chip and a MOSFET? Will either of these work at very low voltages, so that I can get motor response anywhere from 0.1V to 3V? Do I need some sort of diode or resistors in the path to prevent back currents or something? What about resistors in the path to the MOSFET gate?
This is, I think, the basic concept:
3Vin ---> flex sensor ---> PWM chip ---> MOSFET ---> motor
Is this an obvious thing? Are there schematics for this anywhere? What can I read or do to get started? Any friendly advice is appreciated!
I'd like to drive a 3V DC motor in response to a flex sensor (its just a variable resistor/voltage divider set-up, but it won't handle very much current). Bend the arm, more power to the motor, robot rolls forward faster. This is just an analog voltage divider thing; I don't need digitizing.
I know the flex sensor can't handle enough current to drive a motor, so I need some sort of separate amplifier. I know how voltage dividers work. Should I use an op-amp, or do you not drive motors with an op-amp? Should I use a PWM chip and a MOSFET? Will either of these work at very low voltages, so that I can get motor response anywhere from 0.1V to 3V? Do I need some sort of diode or resistors in the path to prevent back currents or something? What about resistors in the path to the MOSFET gate?
This is, I think, the basic concept:
3Vin ---> flex sensor ---> PWM chip ---> MOSFET ---> motor
Is this an obvious thing? Are there schematics for this anywhere? What can I read or do to get started? Any friendly advice is appreciated!