Debugging TV-B-Gone on Mega

Using Arduino Project Guidance
1

Greetings:

I am still to the Arduino and carefully working through various tutorials and beginners projects. I have a number of successful projects under my belt, but I am stumped by the TV-B-Gone build from Ken Sherrif's blog: Improved Arduino TV-B-Gone

I am using the Arduino Mega (2560), and it appears I have everything squared away on the software side with respect to the libraries -- and a user comment indicated that it was necessary to use pin 9 instead of 3, which also requires a respective change in the main.h file. No errors in compiling or uploading. I tried the code using both pin 9 and pin 3, but no luck. I have inspected and reinspected the build on my circuit board, and cannot seem to find any problems.

So, here are my questions:

  1. What is a recommended way of debugging or identifying the source of the problem when you cannot "see" the action. In other words, if I was running a servo, I guess I could see whether the motor was turning. But, since I am dealing with an infrared LED, I am not able to "see" whether it is working -- is that correct? If so, what do you recommend for identifying the source of the problem?

  2. When I press the button switch, I can observe two short blinks followed by three really short blinks -- is this helpful for debugging?

  3. I have a general purpose npn transistor -- mine is 2n3904, whereas the transistor on the site is 2n4401 is used. Is that a potential problem?

  4. Any other thoughts on how to proceed? Again, keep in mind that I am a novice, so really technical descriptions will probably not be well understood, but I am committed to doing my homework!

Thanks in advance.

Brian

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Ok, I got it working -- I think it was my power supply. That is, I have a 9v battery I was using to connect to the board to make it portable. When I plugged the board into my computer, the onboard LED was much brighter and it worked. Can I just attribute this problem to a low 9v battery?

3

beperron:
Ok, I got it working -- I think it was my power supply. That is, I have a 9v battery I was using to connect to the board to make it portable. When I plugged the board into my computer, the onboard LED was much brighter and it worked. Can I just attribute this problem to a low 9v battery?

Not so much low as much as low current capablities. If you try to draw too much current from one it's output voltage just sags no matter what the state of charge of the battery is. Build a pack out of 6 series connected AA alkaline cells and you will be much better off.

Lefty