Reliable CO2 Cartridge Puncturing for Horizontal Acceleration Test

[bobfrancis1980]

There are some magnet drop experiments in the literature and I want to try an alternative experiment to determine if the magnetic fields affect inertial mass.

I am designing a submarine shaped enclosure where I will have either two 2"OD 1/4"ID 1"thick N42 magnets with their opposite poles together or two 2"OD 1/4"ID 1"thick N42 magnets with their like poles bolted together. I will weigh all components besides the magnets, assembly the magnet objects, attach an Arduino Nano with an accelerometer and battery. This will all be enclosed in XPS foam with a 3D printed PLA outer shell. There will be eyelets on the shell to slide along a horizontal fishing line.

At the back of the submarine shaped object will be a hole for a CO2 cartridge. My biggest problem is trying to come up with a way to puncture the CO2 cartridges. Electronic or a spring is fine, I don't care. I just can't find the parts or designs for a simple puncture pin device that I can place with the end of the CO2 cartridge inside the puncture mechanism and then hit a button to puncture it.

Any ideas on how I can do that?
Bob

 

[berkeman]

Welcome to PF, Bob.

Have you looked into the mechanisms that are used in buoyant vests (like in Personal Flotation Devices or diving Buoyancy Compensators)? That might give you a place to start.

https://www.boatspecialists.com/seachoice-inflatable-pfd-manual/auto-activation/

https://www.amazon.com/Lyuwpes-Infl...ing-Swimming/dp/B072295N17/?tag=pfamazon01-20

 

[renormalize]

Your question, as focused on CO2 cartridges, seems like a good fit for Physics Forums. But your statement:

There are some magnet drop experiments in the literature and I want to try an alternative experiment to determine if the magnetic fields affect inertial mass.

gives me pause. Are you attempting to test the feasibility of something like a "CRAFT USING AN INERTIAL MASS REDUCTION DEVICE" as patented by S. Pais and assigned to the US Navy? If so, please take heed: that sort of pseudoscience is not appropriate for discussion on PF.

 

[DaveE]

I'm reminded of that old grad school joke: "6 weeks of working in the lab can save you from spending a few hours in the library"

This sounds like a great experiment for learning about lab technique, error analysis, etc. But James Clerk Maxwell et. al. told us the answer 150 years ago. So go for it, but realize you won't revolutionize physics in the process. To think outside of the box, you first have to know what's in the box.

 

[bobfrancis1980]

Your question, as focused on CO2 cartridges, seems like a good fit for Physics Forums. But your statement:

gives me pause. Are you attempting to test the feasibility of something like a "CRAFT USING AN INERTIAL MASS REDUCTION DEVICE" as patented by S. Pais and assigned to the US Navy? If so, please take heed: that sort of pseudoscience is not appropriate for discussion on PF.

I have no intention of discussing the purpose of the experiment. I should have crafted my post more carefully.

 

[bobfrancis1980]

I have used Autodesk Fusion 360, I have a 3D printer, and I have a CNC router so I am not above designing the case and parts but I just haven't seen a simple method for retracting a puncture pin and then releasing it on the web. Not too many people messing with CO2 cartridges outside of CO2 cars that are on a track.

I wanted to run dozens of runs of propelling the 'submarine' along the fishing line guideline so it can't be a one-off solution.

I will look into inflatable life vests, thank you.

 

[Tom.G]

Oops. missed your last post, Google search did list some electrically powered puncture devices. Also some ideas at: https://maker.pro/forums/threads/electronically-puncture-co2-cartridge-how.30919/

There are (or at least were a few decades ago) low-cost tools to puncture CO2 cartridges available in hobby stores.

Think a ball point pen, with the spring set to push the point out instead of in. The pen cartridge sticks out other end (top?) of the body. When you pull back on the top of the pen cartridge, the tip retracts. Let go, and the tip suddenly protrudes, powered by the spring.

Now to refine it:
The pen tip is replaced with a sharp, tapered, point to puncture the cartridge. There is an adjustable stop to control how far the tip protrudes when released. This way the size of the puncture hole in the cartridge is controlled.

The whole assembly is made of metal.

I tried a Google search but could not find a search term that showed anything useful.

Cheers,
Tom

 

[bobfrancis1980]

Thanks Tom, I think you have pulled things together for me. I found a puncture pin here:
https://www.midwesttechnology.com/abs-co2-dragster-electronic-raceway-firing-pins/
I could3d print a housing and place a heavy duty spring on the threaded part with a nut on the end. Then pull back on the nut to compress the spring and release. Thank you.

 

[bobfrancis1980]

I have figured out where I want to run the level, horizontal 100lb break strength fluorocarbon fishing line. I have a long wooden ramp up to the front door and I would run the line along the longest part of the ramp. I was thinking, in order to have the fishing line completely taut, on one end I could have a 10-20lb spring attached to the fishing line mount point so the spring would provide enough tension instead of trying to rely on my knot making ability.

Do you guys have any suggestions on constructing a taut line for the 'submarine' to move along?

 

[berkeman]

Do you guys have any suggestions on constructing a taut line for the 'submarine' to move along?

Yeah, make it frictionless. If you are trying to make precision measurements of whatever, you need to eliminate the variable of friction in the track...

 

[Tom.G]

Yeah, make it frictionless. If you are trying to make precision measurements of whatever, you need to eliminate the variable of friction in the track...

Good Point!

Consider using a Nylon mono-filament guide line (fish line) and suspending your vehicle on the line with a couple hook eyes.

I like your idea of using a spring to maintain line tension. Another possibility, instead of a spring, suspend some weights from one end of the line. That way the line tension stays constant as the line stretches.

Cheers,
Tom