DMX Clocks

[Suzette]

could have used a DMX clock in my last show to make it spin or to stop at a certain time etc etc could be good for panto as well I geuss

 

Just wondering if anyone knew if such a device does actually exist?

 

'Cinderella' in December, and we would like a clockface with hands in the centre of the front portal. In the ideal world the clock hands would be DMX controlled so we could have the clock "ticking away" merrily during the show, making sure it gets to midnight at the right point in the script....

Even if it cannot be controlled to slowly turn the hands we could at least change the time at the start of each scene and then do maybe 4 cues in the ballroom scene to move the hands from (say) 11pm to midnight during the ballroom.

 

Any clues from anyone if this is possible? Or what might need to be 'obtained' - to make the idea work. I can make the clock face and hands ... but don't know how to control them....??

[peternewman]

Talk to Brian, he's done this before, or search his posts for the unusual props thread, whatever it was called.

[dbuckley]

That was non-trivial to find, lurking in a thread entitled Fresnel lenses.

 

I'm likely to need such a clock too, and have been contemplating the mechanics of such a thing...

[Don Allen]

If you can get a mains clock that runs on 50 hz, you can run it off an audio oscillator.

 

If you want the clock to move to a set point at each cue then a pulse generator that counts what it feeds out. Seems to be a job for a microcontroller such as a Picaxe. need to have an amplifier to boost the signal to the clock.

[dbuckley]

The electronics and software are easy; its the mechanicals that are daunting <_<

[Jivemaster]

Before the days of computers with MS clock and MSF Rugby clocks being cheap, distributed timekeeping was done by pulse driven clocks with a mechanism like a uni-selector this should allow someone to have cues to increment the time by one cue every few seconds.

 

This would allow the clock to approach midnight for the right part of the action, but would not allow the clock to go backwards.

 

http://www.britishtelephones.com/clocks/easycloc.htm

[dbuckley]

Yep, know about the old master clocks, in fact we still have them at work <_< (well, a slave anyway, so that implies theres a master somewhere)

 

What I really really want is a clock mechansim driven by two stepper motors, one for hours, one for mins, suitably geared. I've looked, but cant find.....

[Wuddy]

Pantomimes, Cues and a CLOCK! <_< Ha! Ha! Ha!, you may well need a clock that can run backwards.

 

Seriously, I've seen something similar done in a production which required a clock to keep real time and then speed up to signify the passage of time, this was done using a syncronous clock mechanism and an inverter? I think, which alters the mains frequency and allows control of the clock motor speed.

[Suzette]

Thanks for finding Brian's clock thread - I did several searches but couldn't find it (silly me, not thinking to search for fresnel lens when looking for a panto DMX clock!!)

 

However that is a mechanical/meccano clock and I was really looking for something that can be controlled via the LX desk OR from a separate control, maybe on the side of the stage?

The cable run from the centre of the portal to the prompt desk is about 20metres....

[Brian]

Actually the post of mine you really want is this one.

 

The servo is DMX controlled. DMX at 128 and it stops still, decrease the value and it runs backwards at variable speed and increase the DMX value ans it runs forwards.

[dbuckley]

Beautiful, and precisely what Cinders wants. Or actually, what she doesn't want, but thats a diversion.

 

More details on the meccano piece please, and how exactly did you do the conentric shafts...?

[Brian]

[dbuckley]

Thanks enormously; the concentric shafts is an elegant bodge :)

[dbuckley]

In case anyone else wants to build one of these gizmoids, the gears required to build the 12:1 reduction are:

 

27d Gear Wheel (mod 0,67 - DP 38) 41.4mm (1 5/8") dia, 60 teeth, 8

26c Pinion (mod 0,67 - DP 38) 12.0mm dia, 6.3mm (¼") long, 15 teeth

 

27a Gear Wheel (mod 0,67 - DP 38) 39.4mm (1½") dia, 57 teeth, 8 hol

26a Pinion (mod 0,67 - DP 38) 14.0mm dia, 12.7mm (½") long, 19 teet

 

Having done the research, worked out the bill of materials, the requirement has changed to a digital clock...

[richard]

The other way I've seen this done is just to use an index-able gobo rotator or two (I think someone actually makes a 'clock' gobo rotator that can take DMX actually) and then you can just project the hands, speeding up and slowing down as you wish!