Guys,

I am looking for a little expert analysis of my frustrating situation.

I am monitoring the state of 4 separate IR photo diode sensors, through a single 4 channel op amp then ADC with an Inverting Schmitt trigger to be read by the arduino MEGA on pins 13,12,11,10. All seems well except.. that when one specific sensor (#3 sensor to be exact) is tripped, the "AREF" LED lights up on the MEGA. the other sensors work, but do not Light up the "AREF" LED as #3 does.


My question is why would the "AREF" LED light up with one, but not the other sensors are tripped, when all 4 sensors are wired up the exact same way?

Should this concern me that #3 sensor is not wired correctly?

What causes the "AREF" LED to light up in the first place?

I am worried that the MEGA is damaged in some way possibly....

Thought/Suggestions?

-Ben

 

After taking closer look, it is not "AREF" LED, but is the "L" LED as shown

Sorry for the confusion

Question still stands why only one of my sensors turns this LED on. Why does it turn on in the first place?

 

Welcome to AAC!

Post a schematic so we can see what you're talking about.

What is the "AREF" LED for those of us who aren't familiar with MEGA.

 

Relevant portion of picture for convenience:

 

My question is why would the "AREF" LED light up with one, but not the other sensors are tripped, when all 4 sensors are wired up the exact same way?

Because only one of the pins has an LED on it:

 

Sorry for no schematic, I am at work but will update later.

After reading about the "L" LED (no wonder i was having trouble finding anything on AREF LED....) apparently it is attached to PIN 13

However #3 sensor is attached to pin #11 not pin #13 so I still do not understand why it turns L LED red when tripped.

I will have to double check when i get home that i have inputs going to the correct pins.
Only thing that makes sense is Having inputs wires in on wrong pins somehow and #3 sensor is actually on PIN 13... (lets hope its something that silly).


-Ben

 

Sorry for no schematic, I am at work but will update later.

Always post a schematic when you're talking about circuits. If you don't have one, you're not ready to ask for help.

 

Duly noted, Thank you for your patience with me.

I have tons of other questions for this Project. I may need to start a project thread, as i do not believe this is the right sub forum for them.