That looks like one honkin' big buzzer, lets see if it works like a regular buzzer. It is Arduino time. First load toneMelody onto your Arduino (File -> Examples -> 02. Digital -> toneMelody) which plays the catchy jingle, "Shave and a haircut, two bits." Apologies to those who are more familiar with the inappropriate version which I will not repeat here (for the curious, the second to last word is madre and a description can be found on the Wikipedia page for "Shave and a Haircut"). Anyway, where was I, ah yes, if you have a buzzer or speaker laying around you can test to see what it sounds like by connecting pin 8 (usually) to the positive and ground to the negative. The Arduino Tutorial page has a good description. Next is to get two longish jumper wires, one in pin 8 and the other to ground. We are going to have to flip the board back over to get at the pins for the buzzer:
You might have to flip it back and forth a few times before you find the right ones, they are larger than most of the pins in the area and mine had three (one is being touched by the blue wire in the above image and another is by my finger). Pick two and apply the wires, did it work? Try flipping the wires, now? Try different pins, and? There are only six combinations with three pins (3 choose 2 = 6) to it shouldn't take too long. Also, you might want to adapt the toneMelody code to play on loop so you don't have to keep hitting reset on the Arduino and hold the wires on the pins at the same time, but it isn't absolutely necessary. Success!
Ok, so now we heat up the soldering iron. I can't figure out how to hold my phone and the soldering iron and the CO2 detector all at the same time without burning myself so no action shots, but basically I took a smallish screwdriver and gently wedge it between the buzzer and the circuit board then on the bottom I put the soldering iron on the leg closest to the screwdriver until it is melty and moves. Then I move the screwdriver to a different spot and repeat until all of the pins are out. Got it:
Let's just double check that we didn't fry it. Also, I switched to M-to-F jumper wires now that it is off the circuit board.
Score! Now we are ready to make something with it. I happen to have a photoresistor in my Arduino kit and you probably do too so I thought it might be fun to make an alarm. The photoresistor tutorial is here. We can add that to the breadboard and set up a simple trigger. To minimize fiddling I set the baseline value to the ambient lighting on reset and then the trigger will be when it gets at least 90% darker. If you don't want to figure it out yourself, the code is here. Testing:
Not too shabby. And now to cram it all back into the base and test.
Well that was fun and a little silly, but not very useful...
