ATTiny85 motion switch programming adjustment

Projects Programming
1

Greetings all,

I’m trying to adjust this coding for a motion activated light switch in order to accomplish an extra function: I need there to be nothing happening when LDR_PIN is HIGH. If it’s LOW, then I need it to execute the loop as shown. LDR_PIN is connected to an ambient light sensor, so the lights connected through RELAY_PIN don’t need to come on when it’s detecting strong enough light.

Can anyone tell me what additions I need to make and where to make them?

#define PIR0_PIN 0
#define PIR1_PIN 1
#define RELAY_PIN 2
#define LDR_PIN 3
#define TLED_PIN 4

void setup() {
  pinMode(PIR0_PIN, INPUT);
  pinMode(PIR1_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(TLED_PIN, OUTPUT);
}

void loop() {
  if (digitalRead(PIR0_PIN) == HIGH or digitalRead(PIR1_PIN) == HIGH) {
    digitalWrite(RELAY_PIN, HIGH);
    digitalWrite(TLED_PIN, HIGH);
    delay(5000);
    digitalWrite(RELAY_PIN, LOW);
    digitalWrite(TLED_PIN, LOW);
  }
}

I’m lousy at programming, so any guidance is appreciated.

Thanks!

2

I'm sure it can't be this easy

void loop() {
 
  if (digitalRead(LDR_PIN) == HIGH)) return;  // skip out on the rest of the loop

  if (digitalRead(PIR0_PIN) == HIGH or digitalRead(PIR1_PIN) == HIGH) {

//... what you do now

a7

3 
void loop() {
  while (LDR_PIN) {}; // stay on this line and do nothing while LDR_PIN is HIGH
  // the rest of the code
}
4

Is that the exact formatting? Do I need to add “==HIGH” or anything?

5

What I posted is one format. You can also use what you mention...

warning, bad coding here. See post #9

void loop() {
  while (LDR_PIN == HIGH) {}; // stay on this line and do nothing while LDR_PIN is HIGH
  // the rest of the code
}
6

One is shorthand, and works.
The other is clearer and works as well.

7

How is your LDR wired ?

is a module with a digital output or a bare sensor its own ( which needs a series resistor and an analog read ) ?

8

I’m using the DIYables LDR Light Sensor Module. It has a DO output and it’s adjustable to various thresholds.

9

You need to read the pin, not just test the pin number.

@xfpd was going for a solution essentially identical to the one @alto777 posted, just a different logic to the same effect.

a7

1 Like
10

With a digital output look in the ide examples about digital inputs . You may need a pull up or pull down resistor .

Write your self a simple sketch to red the LDR and adjust it to give the response you want - bear in mind LDR’s are not fast responding

Read this