Convert from char array to 16bit signed int and 32bit unsigned int

A couple of things:

• Never use the atoi family of functions since they have no error handling and may crash if the input format is bad. Instead, use the strtol family of functions.
• Either of these functions is somewhat resource heavy on resource-constrained microcontrollers. You might have to roll out your own version of strtol.

Example:

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>

int main() 
{
  const char* c_sensor_id = "0061176056";
  const char* c_reading1  = " 3630";
  const char* c_reading2  = "-1234";

  c_reading1++; // fix the weird string format

  uint32_t sensor_id = (uint32_t)strtoul(c_sensor_id, NULL, 10);
  uint16_t reading1  = (uint16_t)strtoul(c_reading1,  NULL, 10);
  int16_t  reading2  = (int16_t) strtol (c_reading2,  NULL, 10);

  printf("%"PRIu32 "\n", sensor_id);
  printf("%"PRIu16 "\n", reading1);
  printf("%"PRId16 "\n", reading2);

}

Output:

61176056
3630
-1234