Hi all,
I am designing a line follower. I have the Tamiya dual motor gearbox, which contains two Tamiya FA-130 motors: http://www.superdroidrobots.com/product_info/tamiya_motors.htm They are the first ones on that page. I am going to use my ATMega32 to provide PWM to each motor to control speed.
My question is about the circuit. I will run the two PWM ports to transistors which will switch the motors on/off rapidly. I was going to use simple 2N3904 NPN transistors: http://www.fairchildsemi.com/ds/2N/2N3904.pdf but it looks like the max current through these is 200mA? Apparently the motors use up to 660mA each? Do I need to get different transistors?
Also, once I get the right transistors, how do I determine the size of the base resistor? Also will I need a resistor in line with the motors?
One more question: Should I use a different power supply strictly for the motors? For the ATMega32 I am using a 9v battery through a voltage regulator for 5v. If I use this same 5v for the motors, will the high speed switching for the PWM cause the voltage to fluctuate to the microcontroller?
Thanks!
I am designing a line follower. I have the Tamiya dual motor gearbox, which contains two Tamiya FA-130 motors: http://www.superdroidrobots.com/product_info/tamiya_motors.htm They are the first ones on that page. I am going to use my ATMega32 to provide PWM to each motor to control speed.
My question is about the circuit. I will run the two PWM ports to transistors which will switch the motors on/off rapidly. I was going to use simple 2N3904 NPN transistors: http://www.fairchildsemi.com/ds/2N/2N3904.pdf but it looks like the max current through these is 200mA? Apparently the motors use up to 660mA each? Do I need to get different transistors?
Also, once I get the right transistors, how do I determine the size of the base resistor? Also will I need a resistor in line with the motors?
One more question: Should I use a different power supply strictly for the motors? For the ATMega32 I am using a 9v battery through a voltage regulator for 5v. If I use this same 5v for the motors, will the high speed switching for the PWM cause the voltage to fluctuate to the microcontroller?
Thanks!