Scrambled serial output

[Jerson]

I assume you are using the very same setup that you say had success with. Only difference is you now moved it closer to the acquarium. In this condition, the very same test program which was working further away is now failing in proximity with the acquarium.

Couple of things I would check on.
1 - Check your power supply. Is it rippling more when near the acquarium? Change it to a different make to confirm.
2 - I would look at the declaration of variables and their neighbours to identify which variables could get over-written by a mistaken index into an array. This can possibly over write the suspect variables that you are saying are getting disturbed.

[Amoque]

I assume you are using the very same setup that you say had success with. Only difference is you now moved it closer to the acquarium. In this condition, the very same test program which was working further away is now failing in proximity with the aquarium.

1 - Check your power supply. Is it rippling more when near the acquarium? Change it to a different make to confirm.

This is a good point and brings up the fact that the power supply being used near the aquarium is different than the one used on the bench. Both are from reputable manufacturers and are well filtered, but now... as you bring to mind power issues... I have 15 LED driver boards - cheap, Chinese - 10 watt models nearby (though run from a different source). Also, 8 relay controlled 120V cords hang near; it does not seem unlikely that 60Hz is far more dense in the new location. While the consistency of the error gives me pause, I have said repeatedly here and elsewhere - unexplained problem? Look at power routing and supply. I'll try some additional filtering and perhaps shielding my board. Good catch and thank you.


2 - I would look at the declaration of variables and their neighbours to identify which variables could get over-written by a mistaken index into an array. This can possibly over write the suspect variables that you are saying are getting disturbed.

This seems unlikely, but I will check it; too many times a suggestion to recheck has revealed the problem. I've been working on this for some time, through multiple iterations, retyping portions and rechecking as the version number stacks... Always this issue has persisted; I have just let it slide as other considerations took precedence. Now, as I approach a working version... Just to be sure, you see nothing in the code that causes concern?

Thanks again, even just the opportunity to talk it through is very helpful.

[aerostar]

Make sure you have a good ground connection on the serial cable.

[Amoque]

Adding a short pause (50) after each statement has resolved the serial output issue. Not sure why, but in this case at least, the answer is satisfactory.