Cytron Technical Forum

Those diodes are not for current to flow under normal condition. Please do some reading on H-bridge motor driver circuit and flyback diode.

M3RcY WROTE:The LCD shows the right, left, middle,m_left these commands so i think the sensor is connected. Power for motor also connected, polarity checked, source code for PR 23 also programmed without any changes. i thought is the motor driver L298N problem and i change new L298N and the diode 1N5819 also. but the motor still not work.

In that case, you might need to check the Gnd connection between the M298N with system Gnd (PIC and voltage regulator). You need to check whether the power source you connect to motor is giving power, and the gnd of power is connected too.

What is the output from microcontroller to the pin of motor driver to control the motor at different speed? if the output is high and low only how to control the speed? If the speed is control by microcontroller then what is the output to the pin of motor driver for example the motor speed is 255, 230, 180 and 0.

After i solder the motor driver circuit, i use multimeter to check and i found that when the positive test pen touch the MPWR positive and negative test pen touch the MPWR negative the result is 0 resistance? But if i inverse the test pen the result is not connected. Is that suppose the result?

M3RcY WROTE:What is the output from microcontroller to the pin of motor driver to control the motor at different speed? if the output is high and low only how to control the speed? If the speed is control by microcontroller then what is the output to the pin of motor driver for example the motor speed is 255, 230, 180 and 0.

Microcontroller outputs PWM signal to motor driver. So the pulse width will determines the average voltage of the motor and hence alter the speed of the motor.

M3RcY WROTE:After i solder the motor driver circuit, i use multimeter to check and i found that when the positive test pen touch the MPWR positive and negative test pen touch the MPWR negative the result is 0 resistance? But if i inverse the test pen the result is not connected. Is that suppose the result?

Why are u measuring that? Em...what's the problem that u want to solve? What a component is soldered on the PCB, it might be connected to other devices and that'll not give u the correct measurement.

M3RcY WROTE:After i solder the motor driver circuit, i use multimeter to check and i found that when the positive test pen touch the MPWR positive and negative test pen touch the MPWR negative the result is 0 resistance? But if i inverse the test pen the result is not connected. Is that suppose the result?

Is like what you asked previously, we have 2 pairs of flyback diode (clamping) for each H bridge. During resistance test, the multimeter probe is actually giving voltage and measure the current across the load, though is small is can still forward the diode. Anyway, the polarity should be reverse from what you described.

i wanna ask about the ultrasonic sensor mode..
what type of motor shud i choose so that my ultrasonic sensor can rotate within 180 degree? I want treat the ultrasonic sensor as my robot eyes= =

the easiest would be standard RC servo.