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I have a fried Pie :(

I used a 12 V power supply to this setup. Can you tell me what I did wrong.

Here is my sample code in python: IN1- gpio18 / IN2 - gpio27 / EN - gpio5

GPIO.setmode(GPIO.BCM)
GPIO.setup(IN1, GPIO.OUT)
GPIO.setup(IN2, GPIO.OUT)
GPIO.setup(EN, GPIO.OUT)
GPIO.output(IN1, GPIO.LOW)
GPIO.output(IN2, GPIO.LOW)
p = GPIO.PWM(EN, 1000)  # set GPIO pin as PWM output, with 1000Hz frequency
try:
    p.start(25)
    p.ChangeDutyCycle(25)
    GPIO.output(IN1, GPIO.LOW)
    GPIO.output(IN2, GPIO.HIGH)
except KeyboardInterrupt:
p.stop()
GPIO.output(IN1, GPIO.LOW)
GPIO.output(IN2, GPIO.LOW)
GPIO.cleanup()

enter image description here

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Question

Pie fired - Why?

Answer

There is 50% chance that the pins 1, 2, 3 labelled below are hardwired to Gnd or Vcc. These pins are used for dry run, without Rpi connected. You use a jumper to short the pair of pins to check out if the motor can move.

But if you connect your Rpi GPIO pins to these dry run test pins, Pi fried instantly.

You might use a multimeter to measure the voltages at these pins, or give me the link to the motor driver to check out the schematics to confirm.

motor driver

motor driver 2

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I can't see anything obviously wrong with the schematic.

Likely causes.

  • connecting more than 3V3 to a GPIO
  • connecting more than 3V3 to a 3V3 pin
  • connecting more than 5V to a 5V pin
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  • I think you meant "connect anything other than 3.3/5 V to a 3.3/5V pin". E.g. grounding a 3.3V pin is likely to fry the Pi's DC/DC converter. – Dmitry Grigoryev Jun 17 at 15:39
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You fried your pi because the V+ is wired to PWR+ so you just sent 12V to your pi. There is not much information about this driver board but there is a thread at the raspberry pi forum and someone even made a schematic of the circuit. You can read more info here: https://www.raspberrypi.org/forums/viewtopic.php?t=241060
Appart of V+ being wired to PWR+ there is also an important fact:

The two enables, ENA and ENB, if left disconnected, default to enabled high with 10K pull-ups to Vcc. If you need to control them, the IR2104S shutdown inputs enable at 3V rising and 0.8V falling.

The four inputs, IN1A [the first input for bridge A], IN2A, IN1B, and IN2B, have 10K pull-downs, and 1.25V thresholds. With this, they are 3.3V, 5V, and 12V logic compatible, as long as low is less than the threshold.

I am sorry for your pi but I hope this helps in the future.

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