Sun Motion Simulator

[HerringFish]

I am building a device that moves a light approximately 5 feet and then returns it to the starting point every 24 hours. I would use a standard clock timer switch form the hardware store to turn the light on for the out bound leg of the trip and off while it returns, to simulate the motion of the sun.

I want to use a clock motor to drive a timing belt so that the light carriage moves slowly, following a closed loop out and back. So if I have a 120 inch belt and the clock motor drives the belt with a 5 inch diameter drum it will come “full circle” in the appointed time. Unfortunately, if there is any error in the speed of the system, the start time will advance or slip a little bit each day.

Therefore, I want to use a bigger drive wheel to shorten the trip time so that the light arrives, at the start point, early. When it does, I want the carriage to activate a switch to turn off and power to the motor. Then, at the 24 hour mark, I want a timer to restart the motor and the cycle would repeat itself from the same point each day.

I thought of using a standard digital lamp timer switch to turn the unit on and then activate the on/off toggle to stop it but I would need the carriage to push the button. I also found that the on/off button actually turn off the unit which would ignore the start signal when it is scheduled.

I know that I could just through a controller on it issue but I need the solution to be very simple and very inexpensive. Do you have any products that I could put together to accomplish these functions?

http://files.engineering.com/getfile.aspx?folder=1b8758bc-a53e-40d2-8c3e-6a

This is my old lighting unit for a salt water reef and fish tank. It would have used a screw drive system but it would have to reverse itself. I decided to simplify the design and use a plastic chain drive because it is a closed loop. All that I have to do is to get the light carriage to return early and shut of the motor, then restart on time for the next 24 hour cycle.

What can I use to get this to work?

 

[dpc]

Maybe Google "telescope drive motors".

I have no idea what you are actually trying to do, but there are plenty of cheap off-the-shelf drive systems used on small telescope mounts to follow the earth's rotation.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[HerringFish]

Thank you. I will start researching telescope drive motors.

Succinctly, what I am trying to do:
I want to turn a motor on at a settable time of day and have a contact switch that can turn off the motor until the timer re-starts it again.

 

[dpc]

What does that have to do with following the sun?

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[HerringFish]

I don’t want to follow the sun. I want to simulate the movement of the sun. I want to move the light across the fish tank so that it looks like the a sun light source that is moving.

 

[itsmoked]

Check out Programmable Relays like these:

http://www.factorymation.com/s.nl/sc.2/category.100/.f

I'm sure many would do what you want. Just use your slow motor gearing like you described.

Think also about having it work just like a delayed car windshield wiper system. Something triggers the motor which then runs its cycle until something interrupts it. So all you have to do is turn on the motor briefly with a timer and it stays ON until it reaches the return point. There it will stay until it is briefly turned on again. (using a timer)


Keith Cress
kcress -

http://www.flaminsystems.com

 

[HerringFish]

Thanks
That sounds like it’s on the right track.

Are you in product support for FM?

 

[itsmoked]

No, but I should be as they are a going concern..

I do a lot of jobs with just what they have in stock. It's sort of becoming my one stop shopping spot for one-off industrial control setups.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[OperaHouse]

Reminds me of a system I was asked to do for an exotic bird breeder. They needed lights to slowly come on in the morning to simulate natural conditions. Claim was it would increase breeding rates by 30-40%.

Perhaps you should be thinking intensity too. Consider going all electronic and using 6 lamps instead of moving one. Vary the drive current from one lamp to the next. Nice project for a pic controller.

 

[itsmoked]

Yes, and do it with HBLEDs.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[HerringFish]

Rube Goldberg Maybe?

Yes The actual light “can” will rotate left and right on the carriage. My intent is to add a curved piece of plastic next to the track. I will have a cam follower rolling over it. That way, the can will start the day on the right side of the tank but point to the left, about 30 degrees below horizontal.

As the carriage moves the can to the left, it will rotate down. It will point at a sweet spot as it approaches that spot and then reverse its direction to continue pointing at that point. Finally, it will spot at the far left of the tank and it will again be pointing about 30 degrees below horizontal, only this time, it will point to the right.

This may be a little confusing but it should give a dawn like start to the day, with light passing through most of the length of the tank. Then it will slowly transition until it is pointing straight down over the corals that enjoy high intensity light. At the end of the day there will be the dusk like angle through the water.

The metal halide lamp starts slowly any way but it shuts of abruptly. I could have the lamp pass over a masking screen at the very end of the tank to simulate sun set but I don’t want to go that far.

This will also allow for low light areas in the tank.

 

[HerringFish]

Oh! the coral require Metal Arc lighting. LEDs and getting better but we are late to get really good ones with the right spectra.