working V1

.vscode/.cortex-debug.registers.state.json

@@ -0,0 +1 @@
+[]

simSpeedoArduino.ino

@@ -1,17 +1,52 @@
+#include <Wire.h>                  //for screen
+#include <Adafruit_GFX.h>          //for screen
+#include "Adafruit_LEDBackpack.h"  //for screen
+#include <string>
+
 #define outArrSize 100
+#define DISPLAY_ADDRESS 0x70  //I2C address of screen
+#define SCREEN_BRIGHTNESS 15
+
+//vars for serial communication
 String incomingData;
 char outData[outArrSize];
 
+//vars for screen
+Adafruit_AlphaNum4 disp = Adafruit_AlphaNum4();
+
+
 void setup() {
+  //serial setup
   Serial.begin(115200);
   Serial.println("ready for Data:\n");
+  //setup screen
+  Wire.setSCL(17);
+  Wire.setSDA(16);
+  disp.begin(DISPLAY_ADDRESS);
+  disp.setBrightness(SCREEN_BRIGHTNESS);
 }
 
 void loop() {
 
   if (Serial.available() > 0) {
+    disp.clear();
     incomingData = Serial.readStringUntil(':');
-    incomingData.toCharArray(outData, outArrSize);
+    float speed = incomingData.toFloat();
-    Serial.write(outData);
+    int temp = speed * 10;
+    //int temp = rand();
+    if (temp < 10) { temp = 0; }  // show 0 when stopped and not noise.
+    int digit0 = temp / 1000;
+    int digit1 = (temp / 100) - (digit0 * 10);
+    int digit2 = (temp / 10) - (digit0 * 100) - (digit1 * 10);
+    int digit3 = temp - (digit0 * 1000) - (digit1 * 100) - (digit2 * 10);
+    if (speed > 100) {  //dont show leading 0 if going under 100km/h
+      disp.writeDigitAscii(0, 48 + digit0);
+    }
+    if (speed > 10) {  //dont show 10s digit if less then 10km/h
+      disp.writeDigitAscii(1, 48 + digit1);
+    }
+    disp.writeDigitAscii(2, 48 + digit2, true);
+    disp.writeDigitAscii(3, 48 + digit3);
+    disp.writeDisplay();
   }
 }