Hello
Thanks to all of you for commenting my other topic about the relay h-bridge circuit. I have decided to test my circuit using the l293d h-bridge IC's, complete with microcontroller.
About the circuit. My atmega8 is programmed to read the width of the two servo pulses from a RC receiver. It will output a PWM waveform according to the pulse width, increasing in duty cycle from 1.5ms and descending, and ascending. Like this
Servo pulse width
1ms----1.5ms----2ms
PWM cycle
100%----0%----100%
PORTB pins 3-6 to the l293d input 1-4 goes high or low according to the motor direction.
The circuit in my schematic is working, but as I am not to comfortable with electronics, I was hoping maybe you could help me adding resistors or maybe capacitors to make my circuit more failproof? Caps on the 7905 regulator for more stability? Resistors between atmega outputs and l293d inputs in case of current/voltage spikes? Does the motors need any caps? You don't have to worry about the motor specifications, as I already know I am pushing the l293d's limits of 1.2A peak current per channel.
I appreciate your comments greatly!
edit: I know you usually should use flywheel diodes across the motors, but the l293d claims to have these included in the IC. Is this sufficient?
Thanks to all of you for commenting my other topic about the relay h-bridge circuit. I have decided to test my circuit using the l293d h-bridge IC's, complete with microcontroller.
About the circuit. My atmega8 is programmed to read the width of the two servo pulses from a RC receiver. It will output a PWM waveform according to the pulse width, increasing in duty cycle from 1.5ms and descending, and ascending. Like this
Servo pulse width
1ms----1.5ms----2ms
PWM cycle
100%----0%----100%
PORTB pins 3-6 to the l293d input 1-4 goes high or low according to the motor direction.
The circuit in my schematic is working, but as I am not to comfortable with electronics, I was hoping maybe you could help me adding resistors or maybe capacitors to make my circuit more failproof? Caps on the 7905 regulator for more stability? Resistors between atmega outputs and l293d inputs in case of current/voltage spikes? Does the motors need any caps? You don't have to worry about the motor specifications, as I already know I am pushing the l293d's limits of 1.2A peak current per channel.
I appreciate your comments greatly!
edit: I know you usually should use flywheel diodes across the motors, but the l293d claims to have these included in the IC. Is this sufficient?
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