Question about Arduino Mass Driver
Moderators: kgudger, bfinio, MadelineB, Moderators
Question about Arduino Mass Driver
Daughter is working on this (https://www.sciencebuddies.org/science- ... #materials) as a science fair project. She has all of it built and we have done a lot of trouble shooting but can't get it to move the projectile pas the first coil. I added an led to the breadboard where the hall effect sensor is connected (5v power and sensor) and confirmed it's being triggered. We have also individually tested all the coils. Any help would be amazing!
-
bfinio
- Expert
- Posts: 761
- Joined: Mon Aug 12, 2013 2:41 pm
- Occupation: Science Buddies Staff
- Project Question: Expert
- Project Due Date: n/a
- Project Status: Not applicable
Re: Question about Arduino Mass Driver
Hi - can you describe exactly what you mean by "can't get it to move the projectile past the first coil"? What exactly are you observing? It might help if you take some slow-motion video with your phone if possible, so you can see exactly what is happening. For example, I can think of a few possible scenarios:
1) The projectile initially goes past the first coil, but then gets pulled back toward it --> the first coil is staying on for too long.
2) The projectile gets pulled toward the first coil but then comes to a stop inside the coil --> the coil is shutting off too early, so the projectile is just gliding to a stop.
3) The projectile slides to a stop after the first coil, but doesn't get pulled back in --> the second coil isn't turning on early enough, or the coils are too far apart.
Also, does the projectile easily slide through the tube in general (i.e. if you just tilt the tube and let it slide down)? If the diameter tolerance is too tight and it can't slide easily, you might need to get a slightly bigger tube or try sanding down the projectile.
Hope that helps! Please write back if you have more questions.
-Ben
1) The projectile initially goes past the first coil, but then gets pulled back toward it --> the first coil is staying on for too long.
2) The projectile gets pulled toward the first coil but then comes to a stop inside the coil --> the coil is shutting off too early, so the projectile is just gliding to a stop.
3) The projectile slides to a stop after the first coil, but doesn't get pulled back in --> the second coil isn't turning on early enough, or the coils are too far apart.
Also, does the projectile easily slide through the tube in general (i.e. if you just tilt the tube and let it slide down)? If the diameter tolerance is too tight and it can't slide easily, you might need to get a slightly bigger tube or try sanding down the projectile.
Hope that helps! Please write back if you have more questions.
-Ben
Re: Question about Arduino Mass Driver
1) The projectile initially goes past the first coil, but then gets pulled back toward it --> the first coil is staying on for too long.
^This is what was happening. We had the hall effect sensor oriented as described in the instructions (flat side down), but found that may be the issue. After reorienting the to have the writing down/flat side up it's now pulling in the payload and allowing it to be passed on to the next coil all the way out.
^This is what was happening. We had the hall effect sensor oriented as described in the instructions (flat side down), but found that may be the issue. After reorienting the to have the writing down/flat side up it's now pulling in the payload and allowing it to be passed on to the next coil all the way out.
-
bfinio
- Expert
- Posts: 761
- Joined: Mon Aug 12, 2013 2:41 pm
- Occupation: Science Buddies Staff
- Project Question: Expert
- Project Due Date: n/a
- Project Status: Not applicable
Re: Question about Arduino Mass Driver
Ok - if for some reason reorienting the sensor doesn't work, you should also be able to adjust the delays in the code so the first coil doesn't stay on as long. Please write back to let us know how the project goes!