Copy in example servo code, pwm is way better!

crawler_software/arduino/crawler_slave/crawler_slave/crawler_slave.ino

@@ -1,37 +1,31 @@
-/*
-  Arduino Slave for Raspberry Pi Master
-  i2c_slave_ard.ino
-  Connects to Raspberry Pi via I2C
-  
-  DroneBot Workshop 2019
-  https://dronebotworkshop.com
+/* Sweep
+ by BARRAGAN <http://barraganstudio.com>
+ This example code is in the public domain.
+
+ modified 8 Nov 2013
+ by Scott Fitzgerald
+ http://www.arduino.cc/en/Tutorial/Sweep
 */
 
-// Include the Wire library for I2C
-#include <Wire.h>
+#include <Servo.h>
 
-// LED on pin 13
-const int ledPin = 13; 
+Servo myservo;  // create servo object to control a servo
+// twelve servo objects can be created on most boards
+
+int pos = 0;    // variable to store the servo position
 
 void setup() {
-  // Join I2C bus as slave with address 8
-  Wire.begin(0x8);
-  
-  // Call receiveEvent when data received                
-  Wire.onReceive(receiveEvent);
-  
-  // Setup pin 13 as output and turn LED off
-  pinMode(ledPin, OUTPUT);
-  digitalWrite(ledPin, LOW);
+  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
 }
 
-// Function that executes whenever data is received from master
-void receiveEvent(int howMany) {
-  while (Wire.available()) { // loop through all but the last
-    char c = Wire.read(); // receive byte as a character
-    digitalWrite(ledPin, c);
+void loop() {
+  for (pos = 70; pos <= 130; pos += 1) { // goes from 0 degrees to 180 degrees
+    // in steps of 1 degree
+    myservo.write(pos);              // tell servo to go to position in variable 'pos'
+    delay(15);                       // waits 15ms for the servo to reach the position
+  }
+  for (pos = 130; pos >= 70; pos -= 1) { // goes from 180 degrees to 0 degrees
+    myservo.write(pos);              // tell servo to go to position in variable 'pos'
+    delay(15);                       // waits 15ms for the servo to reach the position
   }
 }
-void loop() {
-  delay(100);
-}