different way to suspend ground glass for vibrating (letus) adapters

[Daniel Rudd]

maybe some of you engineering nerds
....um, uh I mean *geniuses* can answer my elementary question.

It seems like it would be useful to get the gg vibrating at just the perfect frequency and/or ocilation (I don't really know what these words mean--but vibrating just right so you can't see the grain)

1) So what if you had a device that you could turn the power to the motor up and down (potentiometer?) It seems like you could get something like this at radio shack and get one of your nerd/genius friends to solder it between the battery pack and the motor.

I think I read someone else having that idea, but I don't remember if anyone's done it yet.

But here's my (really great) idea.

Quyen's adapter (and I feel unworthy to even write his name) has the gg mounted on suport sticks. Since he has done it, I'm guessing that's probably the best way, but here's my idea anyway.

What if you suspended it from the outsides of the canister with elastic strips/strings. Like a shockmount for a studio microphone.

So four stretchy strings would attach to the corners of the GG and then there would be four tiny holes (located the perfect distance from end of the adapter, and perfectly spaced apart).

My wife puts her hair in a ponytale with these little elastic bands that are stronger and more durable than rubber bands. That might be perfect.

The strings would come up through the holes. Then once you've put the adapter back together, you pull them tight enough and tape them.

here's a beautifully illustrated rendering of this potential design
www.danielrudd.com/media/gg-suspend-4pt.jpg


<or>
you mount guitar tuners (or something like them) on the outside of the adapter, and you can incrementally tighten each string, adjusting the tension to the perfect position.

Combine that with your adjustable power supply and you have the perfect movement (or in the words of the beach boys "good vibrations")

*So somebody tell me why this is stupid before I ruin a nice letus flip.

[Leo Mandy]

I think it is a great idea, but try it on something else before you go into your Letus!

[Daniel Rudd]

ok, please send me your letus.


:)

[Andy Gordon]

I had the same idea a little while ago, I think controlling the GG movement in the Z direction is the tricky part. Having it sliding on something was my initial thought but the friction causes problems. Using magnets with the same poles facing each other was another thought, but it's much easier to use struts as per Quyen's design.

[Daniel Rudd]

hmmm. by z direction do you mean that
The gg will move move back and forth (toward the lens) and not just up/down/sideways?

good point.

I can't belief I 7 minutes writing that post.
My only comfort is that someone else had this idea too... :)

...and I still have my letus. But I must improve the grain visibility.

[Andy Gordon]

Turning off the motor will probably improve the grain visibility.

[Daniel Rudd]

correction: I Must improve the grain INvisibility.

touche!

[Andy Gordon]

Haha... I don't have a Letus so I don't know if this will work, but on my own DIY version based on Quyen's design I made the struts as slender as possible and wired a pot in to vary the motor speed. As the voltage drops the motor slows down and the vibration amplitude increases, hiding the grain better. Still waiting for the right GG to finish testing mine... The weight of the GG has an influence as well, lighter is better. Also the wire connected to the GG can influence the vibration once you have very slender struts.

[Wayne Kinney]

Quyens first tests were with rubber bands and beads on his 'cup35' design way back last year.

[Solomon Chase]

Already did this. Eyelet screws, PVC tube, black rubber hair bands (the ones you mentioned) and diffusion screen.

Works good, need one of those coin vibration motors to complete it, right now I'm messing around with a toothbrush motor.

[Giroud Francois]

i am currently trying the magnet suspension.
it is the same as the letus35, since you still need a lever to make sure the gg 1) stay in place 2) moves only on one plane.
the advantage would be that there no need for a motor (magnetic coil generating vibrations) , you can master the amplitude and frequency of the vibration , there would be less noise or vibration transmitted to the body.
Currently a purchased very small magnet (but very powerfull, perhaps too much). 2nd stage will be to suspend all the stuff in to magnetic field and make sure it in place in place

[Forrest Schultz]

Daniel Rudd is like the most hilarious guy on here. good job. about the vibration, the amplitude of vibration does increase as you decrese the voltage to the motor. which is a good thing, becuase it causes more x and y movement and displaces the grain better. i tested that out a while ago. and wieght is important, but its really not too touchy. i vibrated a fat condesner lens about the size of a small dog and it vibrated fine. it would have done better with a slowr motor speed.

[Ben Winter]

Originally Posted by Daniel Rudd

I think I read someone else having that idea, but I don't remember if anyone's done it yet.

That was me. :)

And no, I haven't done it yet, but I do have high hopes for it. I think I'd probably get a 3mA 1k pot, which gives me 3V max current and a good spread. Someone electrically inclined correct me here?

[Andrew Todd]

ben, how is your letus setup now? ive changed the sticks in mine and have them mounted with silicone to allow more movement. im always trying out new things to find the best quality pic. interested to see how yours is coming along

[Daniel Rudd]

Originally Posted by Andrew Todd

ben, how is your letus setup now? ive changed the sticks in mine and have them mounted with silicone to allow more movement. im always trying out new things to find the best quality pic. interested to see how yours is coming along

Andrew, aren't you going to tell us if this has helped? Where you struggling with noticeable grain patterns? DV or HDV?