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Pico MicroPython L298N DC motor driver and N20 DC gear encoder motor programming design notes, Part 1.

Now I am writing a micropython function to do PWM speed/movement control of the N20 motor movement. The function spec/user requirement is described below.

Tshirt Folder Functional Spec v0.1.

Move the L298N controlled N20 DC gear encoder motor 180 degrees, in a couple of seconds, with a couple of degrees accuracy.

I first move the abstraction level from L298N driver to N20 motor. So from now on I will work at the motor level, rather than driver level. Below is the function to move motor forward and backward at full speed.

def testN20V01(): # *** Move N20 motor at full speed for 2 seconds forward, 2 seconds backward ***
    printProgramName()
    print('Begin testN20V01(), ...')
    n20StopMotor(l298nEnblPinNum) # Setup/Config motor
    n20SetDirForward(l298nIn1PinNum, l298nIn2PinNum)

    n20MoveFullSpeed(l298nEnblPinNum) # move motor full speed, 4 seconds
    pause(fourSeconds)
    n20StopMotor(l298nEnblPinNum)

    n20SetDirBackward(l298nIn1PinNum, l298nIn2PinNum) # move motor backward, full speed, 4 seconds
    n20MoveFullSpeed(l298nEnblPinNum)

And the complete program listing: penzu.com/p/3aff5b07

Suggestion to use a stronger motor. As I said earlier, we need a stronger motor to flip the flap. Yous with no reduction gear is too weak, mine even with gear is also too weak. So I searched my junk box to find a strong guy. I used it for my other Micky Mouse toy project, a cat food feeder. The motor is used to open a flap, so the cat food biscuits would fall to the bowl, ...

The product sheet is list below. You might like to follow my experiments to see if I have any luck.

And I upload the spec for reference.

I noticed that the no load current is 200mA, rated current is 2A, and the stall current is 5.5A

This reminds me one of the ways to "sense" that the T-shirt folder flap has reached either of the two limiting positions, motor current suddenly jumping from 2A to over 5A. At these two positions the program would stop moving the motor. Another way is to use position sensors such as a Hall effect sensor.

So this guy is using a Hall effect sensor:

Now I have mounted the ChiHai motor to my testing gear. The ChiHai motor also has an encoder and the 6 pin connector is identical to the N20 motor. So all my software for N20 can readily moved to ChiHai 4632-370.

Another closed loop feedback control signal is from the switching regulation PSU, eg LM2596 2A max PSU. For the T-shirt folder machine, if the flap is at either limiting position, the motor can no longer move, so will stall at this point, now the current will suddenly jump from about 2A to the stall current 5A. however, the short circuit current protection circuit of the LM2596 would take off, prevent damaging the PSU and motor.

I watched Ty's video a second time, and found many more things inspiring.

And Texgraff is fully automatic!