As the Swedish Chef would say, "Everyting is okey dokey" now...
I added some photos so you could see what I did for connections to all the bits and pieces. Essentially I used a bare breakout board from an UNO and used it to mount the DS3231 RTC and the Bluetooth HC-05 on top of the MEGA 2560.
The LDR (light dependant resistor; far left side of photo) in the second photo is mounted on a piece of scrap cardboard. Typical three wire connection, V+, GND and output (there is a resistor on the back side of that cardboard you can't see 4K7 or 4.7K):
GND--->resistor-->output<-->LDR--->Vcc
The Bluetooth HC-05 is connected to Serial1 on the MEGA.
For power I almost always use the same setup. A typical wall wart DC jack and a bridge rectifier (2A). You can see that in the third photo. The output of the bridge (+ and -) feeds a DC to DC buck converter. The output of the converter I set to 7VDC and connect that to the DC power jack on the Arduino. The reason I do it is two fold. First I can grab almost any DC adapter without worrying about polarity of it. Secondly, when you power the Arduino via the DC jack, anything over about 6.75V is dissapated in heat. Thus you can feed it 9-12VDC and it will work, but it runs pretty hot. Whereas feeding closer to 7V keeps the heat to a minimum.
I did try feeding 5VDC from the converter to the Vin pin on an Arduino, but I cooked the regulator when I did that. So I've just gotten used to feeding the DC jack on the MEGA.
ParolaClkV2.zip (6.54 KB)
