I have a situation here.... so I have the Arduino monitoring a data line... i.e. connected to another chip. If it detects logic 1 on this line, arduino executes a function.
I noticed a problem just these last few days... I think the cold weather, and static buildup is the cause of this problem. It doesn't always happen everytime, but I can reproduce it with consistency.
If I walk across the room, and touch the rotary knob on my Arduino project, somehow, it generates spurious voltage on this data line I monitor... which then causes the Arduino to execute my function.
The problem is ... it shouldn't do that! I reproduced the problem by walking across the carpet, and then rubbing the aluminum side of it's enclosure, or the acrylic front panel... boom... I can see the Arduino executed the function because it updated the LCD screen.
How can I avoid this "false" trigger? i.e. make it robust so static electricity, won't get interpreted as logic 1 on this data line.
The front panel is plexiglass/acrylic and I can't ground this... so what else can I do?
Will adding a pull down resistor, (data line to ground) help? Right now, the data line is just a direct connection between the chip and the Arduino. Will adding a small value series resistor help, or make the problem worse?
If the "rotary knob" is a potentiometer, try grounding it's case to the Arduino's ground.
What does the "data line" circuit look like? What kind of "data"? i.e. If you can make it ignore a short-term pulse and react to the line being held up or down for awhile, that may solve the problem (you can do that in software).
Capacitors or a resistor across the input may help if those things don't otherwise mess-up your circuit.
It might not be triggering that data line... Maybe something else is going on... You can try grounding the data line or connecting it to 5V (whichever is the normal/standby condition) and if it still glitches, that's not the issue. (Disconnect whatever is driving the input before shorting it to +5V or ground.)
The jumper header is supposed to bridge pins 1-2.... instead, it's hanging there up in the air, it's not bridging anything... so the input to the ATMEGA chip is left floating.... result: affected by static electricity. DUHHHH!
Due to my bad eyesight and my refusal to wear glasses, I thought I inserted the jumper correctly.
I have (2) boards controlled by the same ATMEGA chip... only one board exhibits this "static electricity" problem, the other works fine. Yup... the problem board is the photo above.
