Hello, I've been looking for a solution on this one but did not see anyone having this (exact) problem - only similar problems but not comparable. Using Arduino Uno (or Nano - both show the same behaviour) I have the following phenomenon:
I am using 4 digital inputs (D2 to D5) Configured as INPUT_PULLUP so internal resistors are used and I can directly connect GND and D2-5 to create a signal (according to documentation when using INPUT_PULLUP then LOW=ON, HIGH=OFF) So far nothing special... Now, when I create a signal on D2 and D3 in short time distances (by directly putting together the cables GND-D2 resp. GND-D3 - no external instruments or sensors used!!) I sometimes get a LOW value on D4 or D5 as if I had created a signal on those pins. But they are isolated! Nothing at all is connected to them! I can see this happen on the serial monitor of the IDE by the serial.print commands I added in the appropriate IF sections. So I expected to see only lines like TAZnew1234.56 or TBZnew2345.67 from D2 and D3. But sometime I also get TAS1234.56 or TBS2345.67 from D4 and D5
Here is the simple code snippet:
void setup() { //================= pinMode(1,OUTPUT); pinMode(2,INPUT_PULLUP); //TAZ pinMode(3,INPUT_PULLUP); //TBZ pinMode(4,INPUT_PULLUP); //TAS pinMode(5,INPUT_PULLUP); //TBS pinMode(6,OUTPUT); // reserved pinMode(7,OUTPUT); // reserved pinMode(8,OUTPUT); //reserved RED F1 pinMode(9,OUTPUT); //reserved RED F1 pinMode(10,OUTPUT); // LED1 pinMode(11,OUTPUT); // LED2 pinMode(12,OUTPUT); // LED3 pinMode(13,OUTPUT); //onboard LED //================== digitalWrite(1,LOW); //digitalWrite(2,LOW); //digitalWrite(3,LOW); //digitalWrite(4,LOW); //digitalWrite(5,LOW); digitalWrite(6,LOW); digitalWrite(7,LOW); digitalWrite(8,LOW); digitalWrite(9,LOW); digitalWrite(10,LOW); //red digitalWrite(11,LOW); //yellow digitalWrite(12,LOW); //green digitalWrite(13,LOW); //======================
}
void loop() {
if (digitalRead(2)== LOW){ TAZnew = millis(); Serial.print("TAZnew"); Serial.println(TAZnew); //some more code... }
if (digitalRead(3)== LOW){ TBZnew = millis(); Serial.print("TBZnew"); Serial.println(TBZnew); //some more code... }
if (digitalRead(4)== LOW){ TASnew = millis(); Serial.print("TAS"); Serial.println(TASnew); //some more code... }
if (digitalRead(5)== LOW){ TBSnew = millis(); Serial.print("TBS"); Serial.println(TBSnew); //some more code... } }
=================================================== anyone got any idea why or how this happens? It really messes up the whole system of measuring... :(
Any comments are appreciated.
