arduino pub_pot

#include <ros.h>
#include <std_msgs/Float64.h>

const int pot_pin = A0;

int posicao = 0, sensor = 0;

ros::NodeHandle nh;

std_msgs::Float64 posi;
//std_msgs::Float64 corr;

//void contr_callback(const std_msgs::Float64& msg){
//    termo_pd_escalonado = msg.data;
//}

//ros::Subscriber<std_msgs::Float64> sc("controle", &contr_callback);
//ros::Subscriber<std_msgs::Float64> ss("setpt", &setpoint_callback);

ros::Publisher p("posicao_mestre", &posi);
//ros::Publisher c("corrente_mestre", &corr);

void setup() {
  nh.initNode();
  nh.advertise(p);

}

void loop() {
  sensor = analogRead(pot_pin);
  posicao = map(sensor, 0, 1023, 0, 180);

  posi.data = posicao;

  p.publish( &posi );

  nh.spinOnce();
  delay(20);
}