IR Sensor constantly high

Other Hardware Sensors
1

So, a while back i made this thread:
http://forum.arduino.cc/index.php?topic=527467.0

Made it work, tore it up and put it away. Now i'm back at it and I can't get it to work anymore.

The sketch:

For some reason, the image is not working so here is the link:

The Code

#include <SoftwareSerial.h>

int ldrPin = 1;
int tonePin = 11;
int digitalReadLDR = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(ldrPin, INPUT);
  pinMode(tonePin, OUTPUT);
  tone(tonePin, 36000);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalReadLDR= digitalRead(ldrPin);
  Serial.println(digitalReadLDR);
  delay(500);
}

Now, the resistor is a 220 ohm resistor and the sensor is a tsop2236
Datasheet: https://hackerstore.nl/PDFs/IROntvanger.pdf

The LDR datasheet:

(I might have switched the + and minus poles in the sketch, not in the physical system though)

Now, the problem:
The monitor shows that the value is always 1 (high) as if the LDR is turned on. However, even when I disconnect the LDR it still shows 1 in the monitor as input.

For some reason, image is not working so here the link:

The most simple explanation that saves my own credit, is the sensor busted?
The more logic reason, I am doing something wrong, but what?

2

What you are calling the "LDR" isn't an LDR or anything like. It's an IR LED i.e. the transmitter. So that's the thing you should be driving with the tone() command.

The other thing (TSOP2236) is the IR receiver and that's the one you should be reading.

Oh and it' a bad idea to use pins 0 or 1 on most Arduinos.

Your original names and setup from that old thread made a lot more sense.

Steve

3

Okey thanks for the clarification!

The solution indeed was the pin setting. Pin 2 was working again!

Thanks a lot!

Could you, while we're at it, explain why this can cause errors?

4

Pin 0 and 1 are your Serial interface (aka RX and TX)