We have finished construction of the two stands for the stepper motors/spotlights. We plan to add bridges to it to increase the stability of the structure. The height of the stands have been overestimated so that if need be, we could cut off some of its height to better fit our project. There may be some difficulties connecting the stepper motors to the bred boards (as the stepper motors are now mounted so high above the ground), but this could easily be remedied by soldering additional wires as intermediaries between the two.
We also tried to use our new threading set to thread the shaft of the stepper motor, but this proved difficult because it is difficult to keep the stepper motor's shaft from rotating while simultaneously threading it. We plan to use some sort of tool to keep the shaft steady the next time we meet.
Wednesday, January 28, 2009
Tuesday, January 27, 2009
Construction of the stage
We turned our attention to another part of our project that needs to be completed before the Senior Design Expo: the stage. Initially, we were planning on using a regular table to act as our stage, but because of potential errors and complications that could occur from using one of the provided tables (perhaps light would refract of the table, or it was unsteady...the potential list of problems goes on) we decided to create a stage on which to mount all our necessary equipment on (the stepper motors, stepper, spotlight, camera, etc).
We bought the necessary materials which included plywood, aluminum, screws, and begun working! The basic layout is to create a plywood matting on which we could place on top of any tabletop. On this matting would be a clearly marked of area to act as our stage, while having some leftover space on the matting to erect several stands that will hold the stepper motors and the webcam. The stands will be constructed to a specific height so we can use that height in the calculations we need to make (when finding the person on stage).
Yet another task that we will work on simultaneously with the list of other things we have to do.
We bought the necessary materials which included plywood, aluminum, screws, and begun working! The basic layout is to create a plywood matting on which we could place on top of any tabletop. On this matting would be a clearly marked of area to act as our stage, while having some leftover space on the matting to erect several stands that will hold the stepper motors and the webcam. The stands will be constructed to a specific height so we can use that height in the calculations we need to make (when finding the person on stage).
Yet another task that we will work on simultaneously with the list of other things we have to do.
Thursday, January 22, 2009
Pic Programmer
On Tuesday, we were able to acquire our pic programmer, which we hastily began to work on. Using our own laptop with the necessary software (MPLAB IDE), we immediately took some simple code (to test the functionality of both the programmer as well as our pic) that would light up a LED light, and attempted to test it. But after hooking up the pic to the LED, we were baffled to find that the LED did NOT light up. Initially, we assumed that our code was incorrectly programmed, and proceeded to debug it. But after we found no error, we assumed that we were not using the software correctly. It was only after we brought up our problems with Professor Ihler was the REAL problem found. We had bought a OTP pic: One Time Programmable. Naturally, we did not do this intentionally. But we had overlooked this one piece of valuable information. Good thing we had bought two spares of the same pic.
We now have two paths we can choose to take. We could go ahead and order another pic (this time a RE-programmable one) and work off of that, OR to save money, we could thoroughly test our program on the software simulator, THEN attempt to program on our remaining pics. This approach is extremely risky (as we only have two tries before we are out of options) but is a road we are still contemplating as we have already passed our set budget.
We now have two paths we can choose to take. We could go ahead and order another pic (this time a RE-programmable one) and work off of that, OR to save money, we could thoroughly test our program on the software simulator, THEN attempt to program on our remaining pics. This approach is extremely risky (as we only have two tries before we are out of options) but is a road we are still contemplating as we have already passed our set budget.
Tuesday, January 13, 2009
Using the new lab
Today we decided to test how the stepper motor works when given a step function. So, we have gone to the lab today to use the Arbitrary Waveform generator. And after spending a couple of hours to learn how to use the machine properly, we are able to make the stepper motor move with various step sizes, step speeds, making it start and stop, etc. The results of these experiments will be useful when programming our pic, which we will be the goal of our next meeting provided we are able to acquire a pic programmer. A video of our results will be posted shortly.
Also as an update to our project, we have decided to use a laptop instead of the NSLU. And should we have time after completing the project, we will go back to it. This will allow us to advance in our project without further hindrances.
Also as an update to our project, we have decided to use a laptop instead of the NSLU. And should we have time after completing the project, we will go back to it. This will allow us to advance in our project without further hindrances.
Friday, January 9, 2009
Analyzing the stepper motor
Although we were able to pass enough current to the stepper motor to make it move, we were unable to make it continuously turn in a single direction (it kept turning clockwise, then jumping to counter clockwise, and so forth). So, today's mission was to find any potential wiring problems that may have caused this error. And after a bit of trial and error, we have managed to fix the stepper motor so that it will rotate in the counter-clockwise direction.
However, we have discovered a potential flaw: our stepper motor driver may potentially be hindering the usefulness of our stepper motors. The stepper motors we have purchased have the potential to take 1.8 degree steps; but the stepper motor driver seems to have a 11.8 degree step minimum. As such, unless we are able to somehow circumvent this, our stepper motors will be forced to take such large steps each time to move. This will make our project less accurate than hoped for.
Another issue that has arisen is that to be able to power four stepper motors with enough current each, we would have to go out and buy three more power supplies (we already own one). They cost about $10 each, and as we are already past our set budget, this may prove to be a hindrance to us.
Lastly, we have discussed how to create on which to connect the stepper motor and the webcam. We are thinking of finding some sort of durable material that is both strong enough to hold both the stepper motor and the webcam without snapping, but at the same time light enough so as not to give the bottom stepper motor more weight to move. One potential material is the material which circuit boards are made of.
However, we have discovered a potential flaw: our stepper motor driver may potentially be hindering the usefulness of our stepper motors. The stepper motors we have purchased have the potential to take 1.8 degree steps; but the stepper motor driver seems to have a 11.8 degree step minimum. As such, unless we are able to somehow circumvent this, our stepper motors will be forced to take such large steps each time to move. This will make our project less accurate than hoped for.
Another issue that has arisen is that to be able to power four stepper motors with enough current each, we would have to go out and buy three more power supplies (we already own one). They cost about $10 each, and as we are already past our set budget, this may prove to be a hindrance to us.
Lastly, we have discussed how to create on which to connect the stepper motor and the webcam. We are thinking of finding some sort of durable material that is both strong enough to hold both the stepper motor and the webcam without snapping, but at the same time light enough so as not to give the bottom stepper motor more weight to move. One potential material is the material which circuit boards are made of.
Thursday, January 8, 2009
Stepper motor funcitonal!
Success! After thinking about our problem of not having enough voltage being passed to the stepper motor, we realized that the resistor we had put there was limiting our voltage input. As such, by removing it, enough voltage was now being passed to the stepper motor to make it move. Now to resolve the problem of how to make it turn in an angle of less than 180 degrees (as that is what it is currently doing).
Tuesday, January 6, 2009
Return from the Break!
After the long Winter break, we have once again resumed our work on the Senior Design Project. Turning our primary focus now onto the stepper motor, we have attempted to connect the correct wires to the stepper motor driver, and make connections between the stepper motor and its respective driver. This proved to be somewhat successful, as we have confirmed that our stepper motor does indeed work (it managed to turn), but connections between it and the stepper motor driver did not succeed as planned. We believe the problem to be a lack of source voltage, as the supplied voltage seems to be insufficient when tested with a multimeter. More analysis on how to resolve this issue will be conducted.
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