How to write a state change (edge detection) using analogRead() on Arduino? - arduino

Question

I'm having trouble creating a toggle switch using an analog input connected to an RF receiver. I'm attempting to make a servo turn 180 degrees when the voltage reads higher than 800 and stay at 180 degrees until the button is pressed again. It only reads higher than 800 when I press a button on my key fob (RF transmitter). In my code it does this, but it doesn't hold at 180 degrees and wait until the button is pressed again to go back to 0 degrees.
#include <Servo.h>
Servo myservo;
const int analogInPin = A0;
int led = 13;
float sensorValue = 0;
void setup(){
Serial.begin(2400);
pinMode(led, OUTPUT);
myservo.attach(6);
myservo.write(0);
}
void loop(){
sensorValue = analogRead(analogInPin);
Serial.print("Voltage Output = ");
Serial.print(sensorValue);
Serial.println(" ");
delay(100);
if (sensorValue > 800) {
digitalWrite(led, HIGH);
myservo.write(180);
delay(100);
}
else{
digitalWrite(led, LOW);
myservo.write(0);
delay(100);
}
}
EDIT: I'm pretty close with this edited code. I added a variable and an if statement. It turns the LED on and it stays on, but when pressed again it doesn't turn off. So close...
const int analogInPin = A0;
int led = 13;
int ledState = 0;
float sensorValue = 0;
void setup(){
Serial.begin(2400);
pinMode(led, OUTPUT);
}
void loop(){
sensorValue = analogRead(analogInPin);
Serial.print("Voltage Output = ");
Serial.print(sensorValue);
Serial.println(" ");
delay(100);
if (sensorValue < 400 && ledState == 0) {
digitalWrite(led, HIGH);
delay(500);
ledState == 1;
}
if (sensorValue < 400 && ledState == 1) {
digitalWrite(led, LOW);
delay(500);
ledState == 0;
}
}

Answer 1

OK. I think I solved it! Take a look. It now turns the LED on when the button is pressed and stays on until the button is pressed again. This is how to create a switch using an analog input reading.
const int analogInPin = A0;
int led = 13;
int ledState = 0;
float sensorValue = 0;
void setup(){
Serial.begin(2400);
pinMode(led, OUTPUT);
}
void loop(){
sensorValue = analogRead(analogInPin);
Serial.print("Voltage Output = ");
Serial.print(sensorValue);
Serial.println(" ");
delay(100);
if (sensorValue < 400 && ledState == 0) {
digitalWrite(led, HIGH);
delay(100);
ledState = 1;
Serial.println(ledState);
delay(500);
}
else {
if (sensorValue < 400 && ledState == 1) {
digitalWrite(led, LOW);
delay(100);
ledState = 0;
Serial.println(ledState);
delay(500);
}
}
}