Banana Pi BPI-Leaf-S3+MicroPython:Use ADC measuring potentiometer to control the motor

Webduino & Arduino STEAM education BPI-Leaf-S3/BPI-PicoW-S3/Centi-S3
1

Hardware preparation

Hardware_overview2

  • Potentiometer x 1
  • TB6612FNG module x 1
  • 5V DC motor x 1
  • Some wires for connection

BPI-Leaf-S3 :

The ESP32-S3 chip on the BPI-Leaf-S3 has two ADC analog to digital converter integrated inside the chip, measuring from 0mV to 3100mV.

Two ADC modules each have 10 measuring channels, ADC1 measuring GPIO1 ~ 10, ADC2 measuring GPIO11 ~ 20.

Use ADC to read the voltage value of the potentiometer

A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.

How to connect

Potentiometer BPI-Leaf-S3
GND GND
VCC 3V3
S 14

MicroPython Code

from machine import Pin,ADC
import time
adc14 = ADC(Pin(14),atten=ADC.ATTN_11DB)
#adc14 = ADC(Pin(14)）
#adc14.atten(ADC.ATTN_11DB)
while True:
    read=adc14.read()
    read_u16=adc14.read_u16()
    read_uv=adc14.read_uv()
    print("read={0},read_u16={1},read_uv={2}".format(read,read_u16,read_uv))
    time.sleep_ms(100)

When the hardware connection is correct, after the program starts to run, it will continue to get three data at intervals of 100ms

  1. ADC.read() function reads ADC and returns its values, ESP32-S3’s ADC returns 12bit precision data.
  2. ADC.read_u16() function reads ADC then returns 16bit data.
  3. ADC.read_uv() function takes an analog reading and return an integer value with units of microvolts uV . The return value only has’mV’ resolution(meaning it will always be the multiplier of 1000 microvolts.

Use ADC measuring potentiometer to control the motor

How to connect

Potentiometer BPI-Leaf-S3
GND GND
VCC 3V3
S 14
TB6612FNG BPI-Leaf-S3
PWMA 11
AIN2 13
AIN1 12
STBY 10
VM 5V
VCC 3.3V
GND GND
TB6612FNG Motor
AO1 Motor N pole
AO2 Motor S pole

MicroPython Code

from machine import Pin,ADC,PWM
import time

adc14 = ADC(Pin(14),atten=ADC.ATTN_11DB)

PWM_A = PWM(Pin(11)) #Set PWM output pin
PWM_A.freq(20000) #Set PWM frequency
PWM_A.duty(0) #Set PWM duty cycle
AIN1 = Pin(12,Pin.OUT)
AIN2 = Pin(13,Pin.OUT)
STBY = Pin(10,Pin.OUT)
AIN1.on() #MOTOR forward
AIN2.off()
STBY.on() #When STBY pin is at high level, TB6612FNG starts.

while True:
    read_mv=adc14.read_uv()//1000
    if read_mv <= 3000:
        duty_set = int(1023/3000 * read_mv)
    else:
        duty_set = 1023
    PWM_A.duty(duty_set)
    Duty_cycle = int(duty_set/1023*100)
    print("ADC_read={0}mv,Duty_cycle={1}%".format(read_mv,Duty_cycle))
    time.sleep_ms(100)

wiki page: https://wiki.banana-pi.org/BPI-Leaf-S3