Demo sketch showing how to configure a Digistump Oak's wifi manually without a Particle connection

OakManualWifi.ino

SYSTEM_MODE(MANUAL);

#include <ESP8266WiFi.h>

//Static IP stuff
char SSID[] = "yournetwork";    // your network SSID
char passwd[] = "yourpassword"; // your network password

void setup()
{
  pinMode(LED_BUILTIN, OUTPUT);
  
  //don't save these details
  WiFi.persistent(false);

  //start the WiFi connection process
  WiFi.begin_internal(SSID, passwd, 0, NULL);

  //wait for WiFi to connect
  while (WiFi.status() != WL_CONNECTED)
  {
    digitalWrite(LED_BUILTIN, HIGH);
    delay(100);
    digitalWrite(LED_BUILTIN, LOW);
    delay(100);
  }
}

void loop() 
{
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second  
}