diff --git a/platformio.ini b/platformio.ini
index 2eec753..1238fc1 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -21,6 +21,7 @@ lib_deps =
   Adafruit_GPS=https://github.com/adafruit/Adafruit_GPS/archive/refs/tags/1.7.0.zip
   SoftwareSerial=https://github.com/plerup/espsoftwareserial/archive/refs/tags/6.16.1.zip
   Time=paulstoffregen/Time@^1.6.1
-  SolarPosition=https://github.com/KenWillmott/SolarPosition.git
+  ESP32Servo=https://github.com/madhephaestus/ESP32Servo/archive/refs/tags/0.10.0.zip
 ;  NeoGPS=slashdevin/NeoGPS@^4.2.9
+;  SolarPosition=https://github.com/KenWillmott/SolarPosition.git
 
diff --git a/src/main.cpp b/src/main.cpp
index b038daf..b28d733 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,7 @@
 #include <Arduino.h>
 
+#include <ESP32Servo.h> 
+
 #include <SPI.h>
 #include <Wire.h>
 #include <Adafruit_GFX.h>
@@ -19,7 +21,10 @@
 #define SCREEN_ADDRESS 0x3C
 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
 
-SoftwareSerial altserial(14, 12);
+Servo servo;
+int servoPin = 13;
+
+SoftwareSerial altserial(5, 4); // rx, tx
 Adafruit_GPS GPS(&altserial);
 
 uint32_t tstamp = millis();
@@ -45,6 +50,7 @@ void init_display() {
   }
 
   display.clearDisplay();
+  display.display();
 }
 
 void init_gps() {
@@ -60,17 +66,27 @@ void init_gps() {
   altserial.println(PMTK_Q_RELEASE);
 }
 
+// void init_servo() {
+// 	ESP32PWM::allocateTimer(0);
+// 	ESP32PWM::allocateTimer(1);
+// 	ESP32PWM::allocateTimer(2);
+// 	ESP32PWM::allocateTimer(3);
+//   servo.setPeriodHertz(50);// Standard 50hz servo
+//   servo.attach(servoPin, 500, 2400); 
+// }
+
 // ///////////////////////////////////////////////////////////////////////////////////////
 // ///////////////////////////////////////////////////////////////////////////////////////
 // ///////////////////////////////////////////////////////////////////////////////////////
 void setup() {
   Serial.begin(115200);
+//  init_servo();
   init_display();
   init_gps();
   wmm_init();
 }
 
-void draw_sunpos() {
+void ui_sunpos() {
   display.clearDisplay(); 
   
   display.setTextSize(1);
@@ -103,6 +119,9 @@ void draw_sunpos() {
   display.print(F("elevation .. "));
   display.print((double)sun.elevation, 4);
   display.println();
+  display.print(F("zenith ..... "));
+  display.print((double)sun.zenith, 4);
+  display.println();
   display.print(F("azimuth .... "));
   display.print((double)sun.azimuth, 4);
   display.println();
@@ -137,15 +156,29 @@ void debug_solar() {
   // Serial.print("Antenna status: "); Serial.println((int)GPS.antenna);
 }
 
+void servo_sweep() {
+  int pos;
+
+	for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
+		// in steps of 1 degree
+		servo.write(pos);    // tell servo to go to position in variable 'pos'
+		delay(15);             // waits 15ms for the servo to reach the position
+	}
+	for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
+		servo.write(pos);    // tell servo to go to position in variable 'pos'
+		delay(15);             // waits 15ms for the servo to reach the position
+	}
+}
+
+
 void loop() {
-  char c = GPS.read();
-  // // if you want to debug, this is a good time to do it!
+  //char c = GPS.read();
+  // debug print
   //if (c) Serial.write(c);
 
-  // if a sentence is received, we can check the checksum, parse it...
   if (GPS.newNMEAreceived()) {
-      if (!GPS.parse(GPS.lastNMEA()))   // this also sets the newNMEAreceived() flag to false
-      return;  // we can fail to parse a sentence in which case we should just wait for another
+      if (!GPS.parse(GPS.lastNMEA()))
+      return;
   }
 
   // approximately every 2 seconds or so, print out the current stats
@@ -167,6 +200,7 @@ void loop() {
       // calculate magnetic declination
       E0000(GPS.latitudeDegrees, GPS.longitudeDegrees, wmmtime, &sun.declination);
 
+      // prepare location and time data to call the sun position API
       cLocation loc;
       loc.dLatitude = GPS.latitudeDegrees;
       loc.dLongitude = GPS.longitudeDegrees;
@@ -191,10 +225,14 @@ void loop() {
       // sun.elevation = location.getSolarPosition(sun.epoch).elevation;
       // sun.azimuth = location.getSolarPosition(sun.epoch).azimuth;
 
+      // servo.write( ceil(sun.elevation) );
+      // delay(20);
+
       debug_solar();
-      draw_sunpos();
+      //ui_sunpos();
     }
   }
 
-  // draw_sunpos();
+  ui_sunpos();
+
 } // loop()