Mechanical Crab Video

Hello,

I've finally got round to making a (low quality) video of my walking mechanism.

https://www.youtube.com/watch?v=VSllR7m1Zwg

Cheers

Looks great, Steve

Some 'slo-mo' video would be helpful for those of us lacking video-game eyesight and reactions.

MichaelG.

You can view youtube videos at 0.25 to 2 times normal speed by going to the settings.

Neil

I should make another video using a 1.5v battery - it works fine on a AAA.

Just to add - I'm using a 9v battery in the video.

.

It's a start, Neil ... thanks ... but I was actually thinking of shooting at a high frame rate, and playing back at normal speed.

Steve's proposed solution should do nicely, though.

MichaelG.

Most consumer cameras don't have very high frames rates. Makes me think about playing with my astro cam that can manage >=150fps, the USB3 version is even faster.

Neil

.

On my iPad Pro 9.7" ...

... The new ones might be better than that ^^^

MichaelG.

The irony... of course built in cameras will be much faster as they don't have to use a USB interface.

On the down side, the tiny chip will mean relatively few photons unless the illumination is very bright (1.1micron vs 3.75 means with a similar aperture my camera will get 12 times as many photons per pixel at the same frame rate).

I suspect that in any other than direct sunlight 240 fps will not give great results.

Neil

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Suspect whatever you like, Neil

Here is one frame from a 40 second video that I tried yesterday, at 240 fps

Subdued daylight from the kitchen window, and main lighting from the iPad's LED.

The image quality is inevitably reduced [to half linear = quarter area] for posting here.

... Depth of field is limited, because I was working at closest focus.

For, quite literally, 'Kitchen Sink' high speed video ... it looks pretty good to me.

MichaelG.

With apologies to Steve, for hi-jacking his thread:

Here is a crop of that image to show why I took the video:

The rectangular blur, roughly centre-frame, is the end of one tine of a tuning fork vibrating at 300 Hz

... Left-Right motion as pictured.

The tine is slotted, and drives the "escape wheel" which has alternate North and South magnetic poles around it.

The video gives a reasonable impression of the motion; but [one day] I probably need to focus closer, and use stroboscopic light, to do it justice.

MichaelG.

Edited By Michael Gilligan on 09/01/2019 00:06:29

I must admit I am surprised. I suppose I am so used to working at very low light levels.

Added another video.

https://www.youtube.com/watch?v=zt9QPdwu0qA

Cheers

Edited By Neil Wyatt on 18/01/2019 16:59:16

Great stuff, Steve

MichaelG.

I'd applaud, but it sounds like it is applauding itself...

Neil

Something odd is going on with cameras - they've improved! Quite ordinary phones take remarkably good photos with tiny lenses.

A few months ago I was taking photos at a dimly lit event. My 8 year old Bridge Camera with a moderately big lens was out-performed by my nephews smart phone. And the Bridge had to be set properly to get decent results while the smart phone 'just worked'. I guess something clever is going on - perhaps combining fast in-camera processing, better sensors, and an optimised match between the sensor and a small high-quality lens? Does anyone know?

Quite worrying that years of painfully learned expertise may have been blown away by new technology, again! If I continue losing touch at this rate I shall have to take up something where stupidity is an asset. Like politics, or trolling...

Dave

Edited By SillyOldDuffer on 18/01/2019 17:55:41

Many thanks Steve for your latest "Crab" video. What a really amusing and ingenious mechanism. I want one!!!!!! John