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Topic: Idea's? (Read 1 time) previous topic - next topic

vaderj

So....
I have created a propane injected potato gun with schedule 40 PVC.  It has not yet blown up on me, but I have absolutely no clue what kind of pressures or temperatures are involved.
Well, an arduino would be great for data logging controlled explosions like this, but I am wondering: does anyone have any clue what, if any, components could be used?
I have checked sparkfun, but they don't really have anything. I certainly don't need them to be very accurate, I would say +/- 10% or less, just temp and pressure.
Ideas?

vaderj

#1
Feb 21, 2010, 09:26 pm Last Edit: Feb 21, 2010, 09:29 pm by vaderj Reason: 1
Amendment : schedule 40 pipe has a bursting point of around 800-900 psi for the size that I am using.  Temperature, well propane has a peak flame temp at around 3600 degrees f according to wikipedia, though I am not sure what kind of pressures or temps are going on in the combustion chamber, but it will toss a potato out there around 150 yards or so!

Coding Badly

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It has not yet blown up on me

I'm surprised the local law enforcement hasn't taken an interest.

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Well, an arduino would be great for data logging controlled explosions like this

I doubt it.  I suspect it cannot perform the A/D conversion fast enough.

vaderj

#3
Feb 22, 2010, 05:16 am Last Edit: Feb 22, 2010, 05:21 am by vaderj Reason: 1
Thank you for your constructive input, but after a little preliminary (see : google) research, one could discover that it is not only legal, but propane potato canons are somewhat popular. And, propane is has a relatively slow burn rate, so as long as the arduino DAC has the resolution to sample at at least 10hz than I should be able to get a few relevant readings.
Thank you though for your informative and related input!

zoomkat

Read carefully what is written on the side of your schedule 40 pipe. There appears to be ~schedule 40 pipe that is not pressure rated. That is the 4" white pipe usually found at homedepot and lowes (has foam type of material inside instead od solid PVC). I've had an interest in simple instrumentation setups for tinkering. A long time ago I got the parts for making a spud gun but they are still out in the shed. Now I think I may use the parts to make a smoke ring generator like below.

http://www.youtube.com/watch?v=00gzWikLGWI
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

vaderj

You are absolutely correct. I dont remember the terms of differentiation between the two types of pvc in question, but its like cellular and non cellular, being that the cellular is foamy one, or at least not solid.  But thats also part of the plan is to rebuild it using clear PCV, which does have lower pressure rating, and thats part of the reason i want to toss a micro controller in the mix; not only for some unique data logging but also to have a remote controller

keeper63

For the temperature readings, you could use a Type K thermocouple (I think). I am not sure what you would want to use for the pressure sensor, though.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

mitch_79

Regardless of whether or not it's fast enough, Mouser has a category for board-mount pressure sensors...
http://mouser.com/Sensors/Pressure-Sensors/Board-Mount-Pressure-Sensors/_/N-6g7qs/

vaderj

#8
Feb 22, 2010, 06:07 am Last Edit: Feb 22, 2010, 06:08 am by vaderj Reason: 1
Cr0sh and Mitch : thanks a bundle, that is exactly what I have spent hours looking for but had not been able to find anywhere!

zoomkat

A piezio electric gizmo might make a quick to react sensor. You might also be able to hack a $6 digital tire pressure gage from Walmart for the pressure transducer in it.
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

RanTalbott

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you could use a Type K thermocouple (I think)

I'm skeptical:  you have a chunk of metal that needs to be heated/cooled to detect temperature.  It's a small chunk,  but it still requires a finite amount of time that's probably longer than the duration of the explosion.

This is way beyond the usual range of experience of hobby tinkerers,  so I think vaderj needs to find a "sensors forum" to ask sensor geeks about what hardware can capture the conditions before asking the Arduino geeks about how to record the data.

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