Far-seeker:
Ok first let's get some corrections of very fundamental concepts out of the way...IANfinity:
We are sending 9V through the Arduino, which takes up 5V, so we now have 4V going to the transistor. So would 4V be the forward Voltage to the transistor?The way you have this wired up the motor is being supplied off the 5V regulator on the Uno board. This is not generally a good idea for motors and other actuators, becase the Uno is limited to supplying a maximum 200 mA through the 5V pin. You may have been lucky and not needed to draw that much current for your motor, but exceeding this can damage the Uno. So when you do get a new motor, make sure it can function at the voltage of whatever power supply you are using (e.g. if you continue to use a 9 V battery, get a motor with a maximum voltage rating higher than 9 VDC). That way it can be directly connected to the power supply and not go through the power loop on the Uno.
IANfinity:
The collector has a current of 600mA or .006A. Correct?No, 1 A = 1000 mA, therefore 600 mA = 0.6 A. Furthermore the 600 mA is the maximum the current that the collector can handle for sustained periods, and more than that will likely damage the transistor. The actual current at any given moment depends upon the voltage and current at the transistor's base. We'll get back to that below...
IANfinity:
So do I just add that current to the current coming from the battery? What would the current from the battery be?The current from the battery will be the total current for the entire circuit. If you hook the motor directly to the battery and have another wire going to the VIN on the Uno board, it will be the sum of the currents drawn by the motor and the Uno (per Kirchhoff's Current Law ). Becasue this isn't a purely resistive circuit, and you don't know a lot of electrical theory, the easiest way to determine the currents present in the circuit is to actually measure them with your multimeter (remember to do it with the meter in series with the point you are measuring).
IANfinity:
We do know how to put a resistor on this setup, we just haven't done it yet. We have 10kohm, 220ohm, and 270ohm resistors (these came in our Arduino kit).When you are using an arduino pin as an output you always want at least a couple hundred ohms on the pin to limit the current to below 40 mA! Otherwise you could permenantly damage the pin on the microcontroller IC. If that happens at best you won't be able to use it reliably in the future.
IANfinity:
My program is just a modified version of the "blink" program, which is what our proffessor reccomended in class. I have pin 2 coded to wait 32 seconds then turn the motor on, "digitalWrite(pin 2, HIGH)", then stop after 6 seconds (which should be enough time to tip the can over, but this would be no problem to edit if need be). You can see the red wire going from pin 2 to the base of the transistor. The black wire connects the emitter to the blue wire which connects to the pin labeled (GND). The red wire connected to the collector is what we connect to the positive part of the motor. The green wire, which is in the 5V pin on the power strip connects to the negative part of the motor. The motor DID turn on with this setup, and seemed as if it would have enough power. The motor did NOT turn on without the transistor.OK, it seems like you have everything connected like a basic low side switch. Which is all well and good, except you don't have a resistor between pin 2 and the transistor's base. This is not a good idea; (as mentioned previously) you always need to make sure the current from an Arduino pin being used as an output is below 40 mA and the amount of current necessary to use this transistor as switch is quite a bit less than 40 mA. I would put at the very least the 220 ? resistor, though you could probably use 10K ? and that would be closer to the optimal biasing.
IANfinity:
The motor says "SuperJack" and "R-3" on the bottom. I can't find any info on it on the web. I found SuperJack's company website, but it wasn't much help. We are probably going to buy a different motor anyways, since we want one that has a gear on the shaft rather than just a smooth cylindrical shaft.Well that sometimes happens, but at least you tried. If you do get a different motor be sure that information about the normal operating values and maximum ratings for both voltage and current are available, either directly from the seller or on the manufacturer's website, before you purchase anything.
IANfinity:
Basically, I want the motor to be able to get enough power for at most maybe 10 seconds, and I want nothing to be fried/ruined in the process.With a few changes to your current design that is certainly possible. First, see if you can wire the positive lead of your motor directly to the battery, not the 5V pin. Second, you probably want to have a diode, a 1N4004 will do, wired in parallel with the motor. Have the end with the end with the light colored band (the cathode) connected to the positive terminal of the motor, and the other (the anode) to the motor's negative terminal. Third, you really should replace the 9V battery with a number of alkaline AA batteries in series. The exact number will depend on if you get a new motor and what type, but 4 to 6 will probably work. Battery holders wired this way should be easy to find, especially for AAs.
Thank you so much!!! That was extremely helpful. Last night, we had a guy that did this project last semester come to help us with the wiring. He didn't seem to know all that much either, but he told us to get 2 9V batteries and use one to power the arduino and the other to power the motor. We attached a fishing weight to our motor, and it wasn't strong enough to spin it fast (using just the 1 battery). So I'm headed out to Radioshack now (bringing some notes I've jotted down about what you've told me), and I'll see if I can find some more appropriate equipment.