# Pin state fluctuation
**URL:** https://discourse.nodered.org/t/pin-state-fluctuation/79647
**Category:** General
**Created:** [8 July 2023 15:02 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647 "2023-07-08T15:02:33Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@WBr](https://discourse.nodered.org/u/WBr)
#### Post date: [8 July 2023 15:02 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647/1 "2023-07-08T15:02:33Z")
I use a wemos mini d1 for a project with my pi and Node-Red
When I provide 3V to a pin (D4/GPIO 2) it should give me "high" state. when not connected it should be "Low"
But when I switch the toggle Node-Red start to act strange...
This is _one_ toggle movement:
cleared the debug and toggled the switch back and got this:
could someone help me with how I can get 1 high when the pin state is high? and only 1 low when the pin state is low?
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [8 July 2023 15:41 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647/3 "2023-07-08T15:41:16Z")
If, each time you change the connection, you get a short sequence of high and low and after a few milliseconds the value stabilises on the correct signal, then that is caused by Switch bounce as it opens or closes. You need to implement debounce logic in the s/w on the D1.
---
### Author:  [@gerry](https://discourse.nodered.org/u/gerry)
#### Post date: [8 July 2023 15:46 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647/4 "2023-07-08T15:46:01Z")
Or if you determine it is contact bounce and s/w doesn't fix it you can put in a hardware debounce circuit
---
### Author:  [@WBr](https://discourse.nodered.org/u/WBr)
#### Post date: [8 July 2023 16:10 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647/5 "2023-07-08T16:10:39Z")
Brilliant! It works like a charm
```auto
const int triggerPin = D4; // Pin to monitor
bool isTriggered = false; // Flag to track trigger status
bool triggerState = LOW; // Current state of the trigger pin
bool lastTriggerState = LOW; // Previous state of the trigger pin
long debounceDelay = 50; // Debounce delay time in milliseconds
long lastDebounceTime = 0; // Time of the last pin state change
void setup() {
Serial.begin(115200);
pinMode(triggerPin, INPUT_PULLUP);
```
```auto
// Read the state of the trigger pin
int reading = digitalRead(triggerPin);
// Check if the current state of the trigger pin is different from the previous state
if (reading != lastTriggerState) {
// Reset the debounce timer
lastDebounceTime = millis();
}
// Check if the debounce delay has passed
if ((millis() - lastDebounceTime) > debounceDelay) {
// Check if the current state of the trigger pin is different from the stored state
if (reading != triggerState) {
triggerState = reading;
// Check for trigger transition from low to high
if (triggerState == HIGH) {
Serial.println(20);
isTriggered = true;
// Add your message or data to send here
} else {
// Check for trigger transition from high to low
Serial.println(50);
isTriggered = false;
```
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [22 July 2023 16:10 UTC](https://discourse.nodered.org/t/pin-state-fluctuation/79647/6 "2023-07-22T16:10:41Z")
This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.