RE: Re: Whoooosh..thud..oh bugger

["Paul Gale" <groups2@xxxxxxxxxxxxxxxx>]

Excellent - looks good.

One question though - are you going to have the star trek door whoosh sound
effect playing as it opens ? ;)

Paul.



> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of Martin Howell
> Sent: 11 April 2007 20:12
> To: ukha_d@xxxxxxx
> Subject: Re: [ukha_d] Re: Whoooosh..thud..oh bugger
>
> Funny you should ask...  Some pics and details are rather
> hastily chucked together at
>
> wwww.grizelli.com/partition/partition.htm
>
> When the door is working properly, I'll add some moving
> pictures as well, ooh er missus.  The drive is disconnected
> at present as SWMBO can't seem to master the knack of taking
> her finger off the switch before (rather than 3 seconds
> after) the door hits the buffers at 40 mph, and I'm worried
> that the whole thing might end up in the garden.
>
> Martin
>
> Paul Gale wrote:
> > Any pictures yet?
> >
> > Would be interesting to see...
> >
> > Paul.
> >
> >
> >> -----Original Message-----
> >> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On
> Behalf
> >> Of Martin Howell
> >> Sent: 11 April 2007 17:56
> >> To: ukha_d@xxxxxxx
> >> Subject: Re: [ukha_d] Re: Whoooosh..thud..oh bugger
> >>
> >> Thanks Simon, not as strange a suggestion as it might seem.
> >>   I originally planned a fully automated system, using a
> >> controller devised by Rodney Hall (on this list, thanks
> >> Rodney), but decided against it on the grounds that it would
> >> be pretty complex - IR beams to trigger both open and close;
> >> obstruction detection; manual overrides etc - and that it
> >> would need too many fail-safes to stop it from squashing
> >> people, and avoid getting Aunt Edna getting trapped in the
> >> lounge for several days while we worked out what had gone
wrong.
> >>
> >> I'm sticking with the simple manual approach for now, with a
> >> series of micro switches to slow the door down for the last
> >> 6 inches of travel and to shut the power off before the door
> >> hits the stops, together with some cushioning of the cable
> >> drive mechanism.  As a last resort (and with higher WAF), I
> >> could disconnect the drive completely and just add a handle
> >> on both sides, though there's still the problem of small
> >> boys closing the door enthusiastically and forgetting to
> >> move all their body parts out of the way...
> >>
> >> Martin
> >>
> >> Simon Pawson wrote:
> >>> I tried this reply last night but haven't seen it yet...
> >>>
> >>> Coming totally from a strange direction....
> >>>
> >>> could you do something with a reversing sensor system for
a car.
> The
> >> bar
> >>> graph of LEDS could be converted to opto-isolators
driving relays
> >> with
> >>> build in resistors to slow the travel.
> >>>
> >>> Might be hard getting a reliable bounce if wall/frame
mounted.
> Easier
> >>> spotting the wall from the door but not so elegant. Could
be set up
> >> as a
> >>> safety measure as well. Child in the way stops (or even
beeps).
> >>>
> >>> Sorry just an odd thought - back to the merlot.
> >>>
> >>> Simon
> >>>
> >>>
> >>> In message <461A91D0.8000200@xxxxxxx>, Martin
Howell
> >>> <martin.howell@xxxxxxx> writes
> >>>> Hmm, this unit from RS gives the 'soft start' I'm
looking
> >>>> for, but not the 'soft stop, which is where the real
problem
> >>>>  lies.  I agree with your analysis of the drive train
> >>>> issues, but I'm concerned that strengthening the
cables and
> >>>> applying more tension will just move the force to the
next
> >>>> weakest part of the drive - the cable fails at
present
> >>>> because of a joint, inserted partly to prevent
breaking a
> >>>> more difficult to fix part of the drive.  I'm looking
at a
> >>>> more simplistic system of forcing a slow down at each
end of
> >>>> the movement, watch this space to see if it works, or
if the
> >>>> whole contraption bursts through the wall into the
garden :-)
> >>>>
> >>>> Martin
> >>>>
> >>>> David Cole wrote:
> >>>>> Martin
> >>>>>
> >>>>> Sounds to me like you need a PWM (Pulse Width
Modulation) drive
> to
> >>>>> efficiently control the speed of the motor.
> >>>>>
> >>>>> Something along the lines of 510-1209 at RS
should do it, this
> >> would
> >>>>> give the acceleration and deceleration whilst
also limiting the
> >>>>> current if the door jammed. Alternatively google
for PWM DC drive
> >>>>> circuit
> >>>>>
> >>>>> You want to ensure that your drive train (cables)
are as stiff as
> >>>>> possible, this is why industrial applications
usually use rack
> and
> >>>>> pinion drives. This may mean increasing the
diameter of the cable
> >> to
> >>>>> ensure that you don't have any stretch which
causes jerk. It
> sounds
> >>>>> like you have a lot of inertia in your system it
may help if you
> >> add
> >>>>> additional gearing which will reduce the speed,
increase the
> torque
> >>>>> but also decrease the amount of reflected inertia
seen by the
> >> motor.
> >>>>> Hope this helps
> >>>>>
> >>>>> Regards
> >>>>>
> >>>>> Dave
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>> --
> >>>>
> >>>>
> >>>> Grizelli Associates Limited
> >>>> IT Project Consultants
> >>>> 2c Nethermoor Road, Middlezoy, Bridgwater, TA7 0PG
> >>>> UK Company registration no. 2468872
> >>>> VAT registration no. 713 1775 49
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >> --
> >>
> >>
> >> Grizelli Associates Limited
> >> IT Project Consultants
> >> 2c Nethermoor Road, Middlezoy, Bridgwater, TA7 0PG
> >> UK Company registration no. 2468872
> >> VAT registration no. 713 1775 49
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
> >
>
> --
>
>
> Grizelli Associates Limited
> IT Project Consultants
> 2c Nethermoor Road, Middlezoy, Bridgwater, TA7 0PG
> UK Company registration no. 2468872
> VAT registration no. 713 1775 49
>
>
>
>
>
>