* motor with encoder speed analysis, 
  * Chihai Motor CHR-16GR-050-ABHL DC 6V 12V 7PPR
  * https://www.aliexpress.com/item/32833392055.html?spm=a2g0o.order_list.order_list_main.33.5e961802fERLUF
  * pwm frequency, duty cycle, speed

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<code>
Encoder motor_pos(18, 5);

WiFiClient client;
MySQL_Connection conn(&client);

void setup() {
  Serial.begin(115200);
  Serial.println("start"); Serial.flush();
  pinMode(23, OUTPUT);
  pinMode(19, OUTPUT);

  ledcAttachPin(17, 1);
  ledcSetup(1, 80, 8);
  ledcWrite(1, 255);
</code>

to rotate motor to precise 2000 position is hard:
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