The "Smoke Operated Relay" and our 'bots.

[Oren Beck]

Recently, I have heard some scary stories of near misses and similar
about our various projects.

Ok folks- so far- we've *NOT* had any bad press of note from these
'bots. Frankly speaking, we're damned lucky to have dodged even any
notable injuries or damages beyond a few bot 'bits burnt.

Time for some reality based evaluation of risk/mitigation factors.

How many of us really have a fire extinguisher of even close to
effective size anywhere near our build area? And are we comfortable
about operating it? Do we even have a working smoke alarm in the build
area if something goes smoking while we're not there? If the answer to
most of those is no, you re avoidably risking Very Bad Things. Both
for you and anyone in that building- but with no less importance- the
entire *CONCEPT* of Fab@Home is at avoidable risk. If you think me
alarmist or silly? you're betting nothing less than lives and perhaps
hackerdom entire on a bad bet.

The only potential difference between one of us having to reset a
tripped alarm or clean up some dry chem - and VERY BAD THINGS is
having smoke alarms+fire extinguishers etc there at all.

As we are doing things like HBP and extruders etc with relay contacts.
that can and do fail by welding. Or some nameless souls- more than a
few.. who simply hardwire an HBP to B+ because " they never leave
their 'bot alone"

Al of that is setup for my main pitch: The "Smoke Operated Relay" It
might be a risk reduction tool worth considering as common sense. The
simplest description is a smoke alarm with some method of cutting
power to that 'bot. There's many ways to do that and some of us might
design a better/safer/cheaper etc version to post here. My two
working prototypes -sadly no pictures..

1- a commercial "In Duct" alarm that has it's supervised normally
closed=opens on smoke or power fail -contacts used to control a
normally open power relay.. This sort of rig will tend to fail "safer"
than other designs. No replacement for a human safety operator- but
it's a backup.

2- Smoke alarm of the "Escape Light" type with a photocell type relay
switched light controller. It's a crude hack that relies on using two
optically coupled UL approved modular devices. same concept- a backup
to us humans as control operators. Legal fictions stop me from
explaining "why" that's important but most of us can fill in the
blanks.

Thanks for not saying Tl,DR!

[tmo]

i have a 5lb halon extingusher mounted to the leg of my desk.

its the only way to go. your desk can catch fire, hit it with the
halon then get back to work in no time. no mess to clean up.

these machines should be labeled as extreme fire hazards but are also
very very safe if operated correctly

i have yet to have a runaway software problem yet but i would think it
would be a good idea to include some safegaurds in the firmware

[abellasr]

Wow, we can't even get Halon Fire Extinguishers over here anymore,
they were outlawed right after Freon? I always had them in the engine
compartments of my boats. I never gave it a thought before but I do
have a Smoke detector and fire extinguisher (by coincidence) just mere
feet from where we run our bots.

On Aug 29, 12:22 am, tmo <tmoph...@gmail.com> wrote:
> i have a 5lb halon extingusher mounted to the leg of my desk.
>
> its the only way to go.  your desk can catch fire, hit it with the
> halon then get back to work in no time.  no mess to clean up.
>
> these machines should be labeled as extreme fire hazards but are also
> very very safe if operated correctly
>
> i have yet to have a runaway software problem yet but i would think it
> would be a good idea to include some safegaurds in the firmware
>

> On Aug 28, 7:25 pm, OrenBeck<orenb...@gmail.com> wrote:
>
> > Recently, I have heard some scary stories of near misses and similar
> > about our various projects.
>
> > Ok folks- so far- we've *NOT* had any bad press of note from these
> > 'bots. Frankly speaking, we're damned lucky to have dodged even any
> > notable injuries or damages beyond a few bot 'bits burnt.
>
> > Time for some reality based evaluation of risk/mitigation factors.
>
> > How many of us really have a fire extinguisher of even close to
> > effective size anywhere near our build area? And are we comfortable
> > about operating it? Do we even have a working smoke alarm in the build
> > area if something goes smoking while we're not there? If the answer to
> > most of those is no, you re avoidably risking Very Bad Things. Both
> > for you and anyone in that building- but with no less importance- the
> > entire *CONCEPT* of Fab@Home is at avoidable risk.  If you think me
> > alarmist or silly? you're betting nothing less than lives and perhaps
> > hackerdom entire on a bad bet.
>
> > The only potential difference between one of us having to reset a
> > tripped alarm or clean up some dry chem - and VERY BAD THINGS is
> > having smoke alarms+fire extinguishers etc there at all.
>
> > As we are doing things like HBP and extruders etc with relay contacts.
> > that can and do fail by welding.  Or some nameless souls- more than a
> > few.. who simply hardwire an HBP to B+ because " they never leave
> > their 'bot alone"
>
> > Al of that is setup for my main pitch: The "Smoke Operated Relay"   It

> > might be a risk reductiontoolworth considering as common sense. The

[Bo Lorentzen]

That is actually a very good thought.

I have managed to torch my laser in a moment of distraction cutting balsa wood...

The MakerBot is all wood, with several heated elements, it have fire-hazard written all over it.

a smoke - relay would be perfect, but I have been looking for some kind of auto-douser I did see some little can long ago to stick over a stove, if it got hit by flames it would break and spray the fire, something to mount over the makerbot would make me much happier to leave it alone.

Bo

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[Jordan Miller]

a 3'x3'x3' argon chamber or vacuum chamber is probably the safest way to go, but it's around $10k. maybe overkill... =]

jordan

[tmo]

you cant get them here anymore either, its really old but still says
its good on the dial, i have a backup one in my kitchen (ABC) that is
not too far away in case i pull the trigger and nothing happens.

you can get halotron or somethign like that its the replacement to
halon and no cleanup necessary when used

[Luis E. Rodriguez]

I actually think we would all gain tremendous insight from these scary
stories so we can avoid them. I am probably the most inept technophobe
lurking here. I am good with following instructions or sitting back
and learning from others. I've had a Makerbot since About Feb. when I
ordered it and really only last night printed something successful
with my heated build platform. I have been lucky in that I have not
had ANY troubles with electronics. After having a friend at CCCKC
calibrate my thermistor I no longer worried about accurate
temperature. After ceremoniously blowing my PTFE barrel I replaced it
with and indestructible plastruder. I wish the tremendous knowledge
base that is this and other google groups would be represented in teh
Wiki assembly instructions, They are good but nothing near say the
build manual for say the DIYLILCNC. Part of the love of this Makerbot
addiction is everyone solving their problems their own way and sharing
them. BUT, really all people REALLY want to do is print EVERYTHING on
Thingiverse! Not sure what I'm ranting about but lets recap and repost
these near death makerbot experiences.

Luis E. Rodriguez