I am trying to help my daughter with a science project and will make her do most of the work however I am hoping someone can help point me in the correct direction with respect to a couple of components that she will need to make the project a success.
The first item is a miniature gear motor, stepper, or servo that rotates very slowly (1-5) rpm and can be programmed to stop at 60 degree increments. Full 360 degree rotation is required.
A mini linear actuator with approx. 4 inches of extension.
I have seen the tutorial with the linear actuator and pushbutton control using the aurdino control that is posted on this website. I would like to have her use those components for the linear actuation part. I just can’t seem to find a motor that is small, inexpensive and very low rpm. We could gear the motor down if necessary and program the 60 degree stops by running the motor for a set length of time after a button press if necessary. Or if there is a small inexpensive stepper that will work with the aurdino that would be great.
Any advise is greatly appreciated. There are literally so many products out there to choose from I am just hoping someone can point me in the right direction.
As usual it is a group project and they have begun to procrastinate but I think I have gotten them in time to make this a good learning experience.
I’ll go with the stepper controller and a small stepper motor. As far as the “shields” go. Can more than one be installed at the same time ? That is can I get the shield for the linear actuator and the shield for the stepper motor and install them on the controller at the same time? Do they “piggyback” on each other ?
My daughter is a junior in high school and this is actually an extracurricular activity through a local bio-engineering section of a college. They meet once a week for a few hours. They are trying to get the kids into bio-engineering but I don’t think they are leading them very well. This is supposed to be a “prototype” device that rotates six blood collection vials and inserts and extracts the needle from the vial automatically. They gave the kids a $100 visa card and told them to “go buy what you need”. They thought they could go to Home Depot. I’ve got 4 girls in a group that can hardly turn a screwdriver. The sequence, precision, and timing of the motions is difficult given the level of their current talent, and I don’t know how they expect these kids to figure this out. I am an industrial controls guy and could do this in 15 minutes with a plc and a few parts, but, they need to buy the stuff, assemble it, demonstrate it, then at the end it stays there. I’ve got them trying to use a simple program from a 3d printer to design the “wheel” with the six vial locations placed at the 60 degree intervals.
It’s really something. These girls are all A+ students, all 1900+ on the SAT but they have no absolutely no clue about the real world. They saw my 3d printer and figured somehow it would just magically crank out what they wanted. I guess they thought they could send it a text. I gave them the CAD software and it might as well have been from MARS. The other three girls all have parents that are really high paid accountant, salesmen, and lawyer. They don’t have a clue and are ready to just go and PAY SOMEONE TO DO IT FOR THE KIDS. I told my daughter she has to at least try. If they buy the components but can’t execute at least they can present a plan, the required components, the reasons for selecting these components, and a vision for how it would work.
They’re supposed to make an “automated” blood vial switching device. 6 vials, start at position 1, needle retracted, push a button, vial 2 rotates into place, needle goes in, push the button, needle retracts, next vial rotates into position needle goes in, and on and on. I think it is supposed to be a “concept” of some sort. Although relatively simple to think of, the actual execution is challenging when you are really trying to make something that actually works on a budget. Brackets and some type of stand to hold things in place will also have to be made. And oh, they also want it to be “battery powered”. Its a tall order for people with absolutely no fabrication, electrical, or programing experience. Because of the linear actuator we’ll probably go over the given amount but that is supposedly ok. I don’t mind spending the $ just so they learn something.
If it will work I will get the shield for the stepper, and hook up the button(s) and linear actuator without a shield.
Can you give us more information about the project itself?
You need to verify which pins on the Arduino are used by the shield. If you plan to add another shield, you need to confirm that the pins used don’t overlap / are not the same as the shield underneath.
The linear actuator suggested operates using normal R/C signals, so you can use any of the 13 digital pins. Just be sure not to use a digital pin which is used by the stepper controller shield.
You are correct to indicate that this type of project does seem a bit beyond the realm of high school students - this would be more for a CAPSTONE project for a final year engineering student since it sounds like it is focused less on student learning and more on the final product.
