Hi all.

Now I may be about to ask what might turn out to be a complected if not a somewhat stupid question as I have found when trying to work it out.

I am looking at creating a pendulum the ones used in clock's,one with a round bob and a long rod.The thing is I would like the pendulum to be made from LED's that would fixed to a pannel lighting up showing a pendulums swing.

The rod length would be around 900mm width around 20mm the bob around 100mm in diameter all made in 3mm LED's.

The hard bit is the pendulums motion.I don't want the pendulum to travel far in each direction maybe no more that 50mm from center each way.I am looking for a smooth transition from left to right passing the center bottom as though the pendulum is swinging smoothly.

I drew this up in Corel draw and used a facility that allowed me to move the pendulum on screen with the center of rotation at the very top of the rod as it would be in real life.What I found was it is very difficult to come up with the LED position that would make the pendulum motion look smooth as the LED'S light up, I had a stepping effect and not linier or too big of a gap between the LED's.

I may have over complicated the explanation but can anyone give any thought whether this task is possible and if so what IC's would be useful.I realize that the amount of LED's that may be required will be quite a lot.

At the moment it's just a project for a bit of fun but if it's doable then I will use it.

Regards Mark

 

What size LEDs are you using ?

If you look at surface mount LEDs you should find some that are quite small. That will allow you to make several complete images of the pendulum. At the top you will always have a problem in that the images overlap.

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Hi 3v0

I was thinking if around 3mm the idea behind that is the smaller the led the more Chance of a better visual flow as the the pendulum swung.My feelings are that even with small LED's it may look as though the pendulum is stepping rather then swinging. Although if I have square surface mount LED's butted right up close I may have a Chance.I haven't figured a suitable LED placement plan out yet.
I think this is not too simple but I thought I would put it to the more experienced people.

What about IC's I could use?

Regards Mark

 

LEDs come with different beam angles. That is how much the light spreads out as it leaves the chips. If they have a diffusion lens that also makes a difference.

I have seen LEDs so small that they were not much larger then a grain of sand. Do not know where to source them. Check places like digikey mouser and newark to see what is out there. Maybe order a few different types to see which you want to use.

There have been several threads about powering LEDs over the last year. Maybe search for and read a few of them.

That still leaves you the logic to control the LEDs. You could go with logic chips but in the end it will be easier to program a micro controller to sequence the display. With the microcontroller you could have the pendulum move slower at the ends of its swing. You could also fade one position out while fading the next in.

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I was thinking it may be that I have to make a lens cover.The overall layout of the LED's may have to be in a wedged arc shape with each line of LED's arced in the pendulums line of flow.More LED's required at the bottom where the bob is.It might end up that each row of LED's as a specific shape in order to the visual effect right.

Regards MARK

 

SMD LEDs-The Electronic Goldmine

These are SMD, but some have leads, all very tiny. Little tough to work with, but I managed. Think it would be much simpler to light a mechanical pendulum.