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Below is an image that shows which pins are connected to VCC. These would be the ones to check for a short against the ground plane (which is the bottom of the board). Sometimes the solder mask gets burned away a bit, and a tiny amount of excess solder shorts against the ground pour.
Yes, I supplied the kits to Maker Shed, so I support them technically. I’m not exactly sure what their policy is regarding replacement, though, so I’d like you to at least ask them whether they replace kits that have defects. They were never clear with me on this policy.
Since you’re an EE, I assume your soldering is good — I’ve found that the most common cause of failure is horrible soldering. You wouldn’t believe some of the soldering I’ve seen. Backwards socket won’t matter. All my boards undergo electrical testing at the manufacturer, but a defect is still possible I guess. I think the most likely explanation is that a solder joint is shorted against the ground plane (bottom of board).
If Maker Shed won’t replace the kit and if you can’t find the short, I can replace the board and components you need. Maybe with some close inspection and reheating of solder joints you can find the problem. Would you need all the parts except for the MCU? I need to keep my replacement costs down…
You would need some hardware to convert composite video to SVGA. But keep in mind that the composite signal output from the TVout library is not perfect (per the standards) and some of these products won’t work with the TVout signal.
Laurent,
The default countdown of 10 seconds is defined here:
#define COUNTDOWN_DURATION 10
You can change that.
The buzzer is driven by a 5V PWM square wave.
Derek,
There’s been some work to create a black or gray background for letters using the Video Experimenter. See this thread: http://nootropicdesign.com/forum/viewtopic.php?f=25&t=2363I used a MOSFET as well as a 4066 analog switch IC to create a gray/black background on certain lines of the output. The background persists for the entire length of the line, but it was effective.
The resource you point to is also very interesting. He’s not using a LM1881 and is simply waiting for the long drop in voltage to detect frame boundaries. Nice work.
Yes, it might be possible to make the countdown go faster. I’ll investigate soon.
Yes, you can change the countdown time from the default of 10 seconds. Hold the red button, but before releasing the red button, press the hour and min buttons to increase the countdown time.
No problem at all, it’s a bit confusing. I chose to leave the PM indicator off because it’s so bright and annoying!
Does the clock make any noise at all? That is, does it beep when you do the countdown?
If yes, then we know the buzzer works.
Are you sure you have the clock and alarm set to the correct AM or PM? That is, if you have the alarm set for 2:00PM, are you sure the clock time is set to PM? Remember that when the clock time is set to PM, the PM indicator light is not on. The PM indicator light is only on when you are setting the time using the hour button.
Yes, that should work fine. I have used a power supply of 11.5 volts, and the regulator gets a bit warm, but not too warm to touch. 9.6V will not cause it to get very warm.
I am happy to refund your money or send a replacement (assembled/tested). Let me know which you would like.
The 100uF capacitor may have been defective.
Now that it is gone, what happens if you connect power? Does the voltage regulator still get hot?
If your power supply outputs clean 9V, then the capacitor is not really required.
