Independent Safety / Fire detection system

Has there been any discussion on independent fire and safety systems? Given the slow printing speed of RepRap, I see might be pretty common to leave it unattended...

I'm thinking of some kind of independent monitoring system that watches the Extruder Head (maybe even hooked into the XYZ position data) and sounds an outside alarm or shuts down the ongoing work. It could also scan for general fire that may develop in the monitored data.

Goal is to catch overheating situations due to alpha or beta quality software, home made electronics, etc Don't want a software crash to leave a heating element on and producing toxic plastic gases!

I really don't have the skills to design such electronics, but not going to keep me from starting research.

I found one project along the lines of what I'm thinking:
[www.appliancemagazine.com]
"Ultra-Low-Resolution Thermal Imaging for Detecting Kitchen Hazards"

Hi RoundSparrow,

... there should be a security-check for overheating and/or the reprap shouldn't be used unadvised!

As i'm trying with laser-sintering and -cutting, i had some thoughts about removing the toxic gases too - for my testing i used a coal-absorber-filter and ventilated the fume through a tube in the garden

When someone uses plastics or solvents, which exhaust toxic or even weak health-relevant gases (most heated plastics do!), then security-measures are a must!

When there is a chance for overheating the material, then too!

I dindn't know exactly, which IR-spectrum cheap web-cams have, but there is a fair chance, that with a good IR-trespassing filter there could be made a cheap IR-camera - maybe someone can look, which vendors have the 'deepest' IR-sensing camera-chips or we remove the IR-filters from normal ones and test ...

Viktor

Edited 1 time(s). Last edit at 11/18/2007 02:11PM by Viktor Dirks.

I just wrote a timer routine into mine that turns off the extruder barrel heater after about five minutes if the polymer pump isn't running. I seriously doubt that mine would ever heat up enough cause a fire problem. The bottom brass flange connected to the extruder barrel has never been above 125 and is usually down around 80. Not insulating the extruder barrel has its compensations.

Viktor, yha, I'm already playing with Linux IR cameras right now for another project (ZoneMinder). I was going to try that; but I also have a Fluke IR temp sensor (hand held) that would seem more ideal. Such a sensor on a motor tied to the host PC. In an ideal world, point it at the xyz coordinates of the extruder head and use it as a way to validate the information RepRap thinks is going on.

I consider this (scanning sensor) an overkill approach. But wanted to toss the topic onto the table.

a simple solution would be to mount a smoke alarm on your reprap machine.

if you wanted to take it further, it would be cool to wire the alarm circuit so that it triggered the machine to shut down as well as make its loud noises.

hmm but what happens if the pump snaps and rotates in the air without feeding any material...?

Do I really dare to have this thing running unattended in my home?

Depends on what you mean by "unattended". If you are talking about leaving it running while you were gone for the weekend, I'd say no. I have no problems leaving mine running while I take a nap. I don't leave it running overnight, though, unless I'm up. I'm well past the time where I have to hover over Tommelise.

mimarob Wrote:
-------------------------------------------------------
> hmm but what happens if the pump snaps and rotates
> in the air without feeding any material...?
>
> Do I really dare to have this thing running
> unattended in my home?

i would not recommend it, yet. like forrest said, once you have it up and running for a while, its fairly safe. but right now, its still very much in the research stages.

once we get to the point where we've had many machines up and running for multiple hundreds of hours and have gotten more design refinements in it, i'd say yes (like, say fire detection and auto-shutdown). also, at some point in time we're going to *need* to do that, as the idea here is to create a human-free print process.

Can someone with more experience than I in electronics help me locate a place to order a reasonably priced "Thermopile array sensor" ($35 or under) that I could hook up to an Arduino? I will need step by steps on what parts I need to order

Basically I want to be able to have something equal to my handheld Fluke IR temp sensor that I can start to play with (connected to a computer via Arduino).