I’ve wired up the car in Project 2, but not getting any power to the wheels. I checked the L298N motor driver with a multi-meter but there is zero power output. I did measure input power to the board (6v +) and the red LED is on. I already replaced this board but same thing, so it seems to be how it’s wired at the board, but I followed the instructions. I see the Enable pins are actually two pins, and I selected the pin towards the edge. The Android WiFi GUI and all esp32 wiring looks fine. Suggestions how to diagnose ?
Are you powering the Motor driver on the “+12V “pin? Do you have the plastic jumper in place? Or did you remove it?
From that photo, everything seems ok. But I don’t know about the rest of the circuit.
How are you powering the ESP32?
It is powered by the power bank (shown in photo under the motor driver. As mentioned, it is connecting to the WiFi and the LEDs are on, so I know the board is working.
It is very difficult to find out what might be wrong.
Do you have another motor driver to experiment with?
As mentioned, I tried a second one. Perhaps I can somehow test the driver in a more simple configuration?
Maybe you can try controlling just one motor.
Did you check the signal that is coming out of the ESP32 GPIOs?
I guess I should know the answer to this by now, but how do I check GPIO signals? On an oscilloscope?
Not necessarily. You could just use a multimeter. Even with PWM you should see an average on your multimeter.. everyone should have a multimeter if working with an Arduino. If you can afford an oscilloscope you can see the waveform of a PWM signal.
If you have an oscilloscope, you should be able to actually see the signal.
If you don’t, as Steve mentioned, you can use an oscilloscope.
Actually I have a small Chinese hand-held oscilloscope and an older large Tektronix scope given to me by a relative. Regardless, I used a standard digital multimeter and got +5v (not +6v) on each pin save for the motor outputs (zero). Interesting, I got 0.5v on each GPIO pin when the esp32 was off (esp32 GRND). If a minimum 6v from the battery pack is required to measure output at the motor output, I can’t get it with just four AA batteries. FYI, the illustration on pg 539 shows AAA batteries.
I’m sorry, but I didn’t understand if you measure the output of the ESP32 GPIOs?
Without anything else, just the output of the GPIOs when controlled with the web server?
The problem may be the with the ESP32. Anything else seems fine to me.
The total of the battery pack was 6V.
I see. I was measuring it where each GPIO connects to the motor board with everything powered on.
If I just power the esp32, this is what I found:
PIN F L R RV S
32 2.6 —————————>
33 0 0 0 3.3 0
25 3.3 3.3 0 0 0
26 3.3 0 3.3 0 0
27 0 0 0 3.3 0
14 2.6 ————————–>
F=forward L=left R=right RV= rev S=stop
GPIO 33 and GPIO 14 are the enable pins. They control the speed of the motors. So, I think that is an expected value.
The other values are also right to control the motors.
So, everything seems fine on the ESP32 side.
I really don’t know what can be wrong :/
Let me know if you find out anything new.
I think you meant GPIO 32 is an enable pin.
This is the second project in a row which I could not succeed, so a bit discouraging ; (
I think failures are good to learn from as long as you can figure out a test plan to determine root cause.
In this case, why would a motor controller not send output signals if it is powered and receiving input signals?
I suppose (low probability) that both boards are defective, but I will buy a few more.
Yes, I meant GPIO 32.
I’m sorry that you can’t get it working – it is very frustrating.
Unfortunately, I really don’t know what might be wrong. Everything seems to be setup properly.
It’s not likely that the two motor drivers are defective, but it’s possible