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09-25-2011, 11:18 AM #1
Off Topic rope or roller chain for light mover
I want to build a system to mover a light in a roughly square/rectangular pattern. Reflector and bulb/socket weighs 5 lbs maybe. Possibly 30" x30" square pattern ? The light will make 3 circuits per hour roughly
Thought about using roller chain on sprockets, and machining a part to use in place of the master link to hang the light from, keep the fixture oriented with 2 bungee cords maybe ? With large sprockets or pulleys I could just use 2, but 4 will be easier to get the pattern I want.
Originally I was thinking about using rope on V belt pulleys but I do not see a simple way to suspend something from the rope in a way that it will run over the pulleys properly.
at the 30x30 square pattern there would be roughly 120" of chain involved, meaning we need to move 360" per hour...will drive with some kind of 120vac gear motor.
09-25-2011, 12:00 PM #2
09-25-2011, 12:45 PM #3
5 lbs of side load for a chain is quite a bit. How much would the lamp be allowed to rise and fall as it makes its way around?
Is the path rigidly defined or do you need to build in some adjustability for different path shapes/extents?
09-25-2011, 01:11 PM #4
Rise and fall is no real big deal. And there can be an idler in the middle of each side too if need be. I realize the roller chain is not made to do the job, just wondering if it will work. Billtodd, that is an interesting idea.
Also considered running something or other on bicycle rims as the pulleys. Not sure if something could be reliably bonded onto the back of a serpentine belt ?
09-25-2011, 01:36 PM #5
I recommend using a Rouleaux triangle. By using this the need for pulleys or complicated mechanisms is eliminated. You can drive the device directly from a centralized motor. Here is an animation of the motion:
A Rotating Reuleaux Triangle - YouTube
The light is placed at one vertex of the triangle. A motor is at the center. Note that the triangle has an eccentric motion. This is provided by a sliding pin drive in the center of the mechanism. The pin drive generates an epicyclic motion necessary for the center of the triangle. Here is alternative design called a Rouleaux rotor which generates a square motion via a circular, rather than epicyclic, drive:
Drilling a Square Hole - YouTube
This can work if you don't mind having a frame that is larger than your light box.
09-25-2011, 02:07 PM #6
It would appear that the Reuleaux triangle has a floating center, but you could suspend some sort of motor from the center, providing a floating reaction bar for it to act against.
I was imagining something more along the line of one of those kids' rides you'd see at the fair, where the bucket dangles from the end a pole, and some mechanism raises and lowers the pole. Now if you had your light cord passing through an eye in the end of the pole, you could probably design a square motion pattern by raising the arm with some sort of sinusoidal motion acting at twice (or 4 times) the rotational speed of the pole base.
How to add this sinusoidal lifting link to the rotating platform would be the tricky part
09-25-2011, 02:12 PM #7
If I am reading the OP's post right, he wants a way to have a single lamp (or lamp assembly) on a conveyor type system.
That's funny you should mention that, I was hired by a company here in California to do just exactly that, with grow lamps .... dont ask me what they were growing, lets just say it's legal here now.
Chain on edge conveyor, set up in a large rectangle 110' x 240', grow lamp cluster weighing in @ 300+ lbs and 7000 watts, conveyor speed is adjustable, but typically runs about .75 FPM, a festooned power cable in the center feeds the fixture.
This system is supposed to simulate night/day conditions and is better for the plants, as well as cut operating costs by not having to run multiple lamps.
These guys pay top dollar for this stuff. Amazing how this money is bleeding over into the legitimate sector now that it's legal.
09-25-2011, 02:21 PM #8
Why doest it have to be a rectangle? A circle covers about 80% the area of a circumscribed square. Light is generally diffuse enough and perception forgiving enough that a small discrepancy in lighting goes un-noticed.
Run the light in a circle a little larger than the proposed square cover the same area and avoid the complication.
Unless glittering complication is a feature of the display. In that case celebrate the complexity with suitable mechanical gewgaws. like use a parallel rule rule motion driven by step motors.
09-25-2011, 02:22 PM #9
Turn the idea round by fixing the chain to act as a sort of rack with the motor and sprocket on the same mount as the light. Need some sort of hanging rail(s) assembly to carry light & motor but there should be stuff around at a sensible price. Have done something similar, albeit only through an arc & turn aside at the the ends using custom Hepco ball bearing rails as the carriers but the price of those things was totally inappropriate for your job. Possibly a lightweight version of the "rectangle with the middle half of a side cut out" used for top hung sliding doors could be found. Or maybe very hefty curtain rail type stuff. I know I've seen something commercially available that would do just fine but an darned if I can recall what it was.
09-25-2011, 03:49 PM #10
09-26-2011, 07:55 AM #11
Using the roller chain as a rack is interesting too, you could use two of them spaced some distance apart, and drive one sprocket and spring load others and let them freewheel.
The cheaper the better :-).
I suppose it might also be possible to just move the PLANTS and leave the light stationary...with the circular path then you could just use a lazy Susan ball bearing. But if there is any hydro involved, them moving the plants would be more interesting...although still possible. I will have a mix of hydro and soil plants. With some thought I suppose the lazy susan bearing could be used to suspend a load as well...with a counterweight (maybe a fan) to balance things out.
For a circular path the bicycle wheel might work just fine...it could be "helped" a bit with a few sealed ball bearings running on the "up" side of the rim side...free at unlimited pickup time..with a freewheel and some chainrings too maybe :-).
09-26-2011, 09:19 AM #12
You could make it a simple rotary system with some extra lamps at the end. when it reaches the corners simple magnetic reed switches would turn on the extra lamps to fill the corners. could even use several stages as it goeas into and out of the corners.
Similar idea to center pivot irrigation systems with short extensions that swing out to water corners.
09-26-2011, 09:37 AM #13
I would think a simple pallet conveyor system would work. Would fit well into a rectangular space, or any other shaped space for that matter. Easy to cordon off areas of light and dark, along with the gradual increase and decrease in intensity. Could also have a watering station.
09-26-2011, 09:55 AM #14
As long as your plants are not calibrated with a micrometer, why can't the edge plants have a slightly different amount of light? What is the specification for the plants, and how do you eliminate the variation in the soil and the plants that makes the light distribution so very critical? How does the customer measure the calibration?
Once you answer all those questions, you simply run the lights in a circle.
Plants are adaptable. And Organic.
09-26-2011, 10:09 AM #15
09-27-2011, 10:43 PM #16
What is the germination of the "Ghost" chilis? I bought a packet of seeds, probably at your insistence, because I mentioned Habaneros as the "hottest". I have not planted them, I do not know if I should plant them indoors, as they are SUPPOSED to grow to about 5 by five feet, dwarf tree size.
To plant them outside precludes starting them now, near October. They would have to be in tubs too large to carry outside, for me, with my bad back, and if you do not have the root space, you will have stunted plants.
Are you growing these to market them? I am not trying to barge in. I grow stuff for myself and my family/friends, and I don't have either who would eat anything hotter than a Jalapeno. I like my Habeneros, most of which I have dried, as you can't really store them, unless you pickle them and that will always take away the heat.
Actually, the older I get, the less I can tolerate the heat. I still love my own horseradish, hotter than hell, but horseradish is a momentary hot. HOT peppers will burn and keep on burning, capsaicin is really volatile, and lingers. Worse is that it burns as much on exit as ingestion.
Regardless, I have to try growing them. Just be careful how I sample the fruit. 1/8 inch piece? That was recommended for Habaneros.
As per other hot peppers, does the flesh have as much heat as the placenta or the seed?
09-28-2011, 08:30 AM #17
They need heat to get any decent amount to germinate. None of my plants have gotten that large, mine this spring were maybe 6" when they went out into 15 gallon planters 4 per planter, now they ate maybe 24" tall. I want to get the plants larger for next spring.
26c-28c is a popular temp. I use a heating pat set on low/stay on, and I prefer to start mine in rockwool cubes known as "aok" plugs
Grodan A-OK Starter Plugs, for plant propagation / cloning at Sunburst Hydroponics
I just got these trays yesterday, had some others that were not as nice
Gro-Smart Tray Insert, for plant propagation / cloning at Sunburst Hydroponics
And put a humidity dome over the flat with 1/2" or so of water in the bottom...then set that whole mess on the heating pad with a meat thermometer stuck in one rockwool plug.
If you dry the pods you can powder them and use as much or as little as you wish. If you like I will be glad to send you a pod of ghost (bhut jolokia) and a chocolate bhut, both dried and you can try them, I have some dried chocolate habs too. They were all dried at 105f so the seeds should be good too :-). I will often add about 1/8 of a tp or so (using the tip of a steak knife to dig some powder out of the bag) to a portion. People smoke then dry the pods too, yet to try that.
If you have tried habs you know they have a funky taste...the chocolate hab does not, nor do the ghost or any of the other hyper hots...and a lot of people do not like that distinctive "funk" of the hab.
here is a very long thread on my HID grow room, that is the one I am enlarging...too cramped, no room to actually get IN there and work around the plants.
Chillis Galore Forums • View topic - A small HID Sun came on in my Garage
09-28-2011, 08:35 AM #18
With the hypers the placenta is the hottest, but the rest of the pod is damn hot too :-). Peppers grow slow, I tend to start WAY early...but 2-3 months is about right probably, I will start some seeds probably November, but maybe a few even sooner. I started some tomatoes last year WAY too early, I would guess they grow 4x to 10x faster than peppers.
09-30-2011, 09:43 AM #19
I apologize if I killed off the discussion about the mechanical solutions. It was not my intent.
Another thought, was to add shades to the light, so that as it rotates, you will have a uniform light pattern under the swept area.
If the light intensity matches the swept radius, then the rotating light/shades will have uniform coverage regardless of the shape and pattern the plants are arranged in.
09-30-2011, 10:13 PM #20
The reflector I have looks like this...
HTG Supply - Maxwing Reflector
So a circular pattern of movement will cause an assymetric light pattern, but the circle at 12 o'clock and 6 o'clock positions will have more light bouncing back from the front and rear walls, so things might equal out fine.
I can always go to a reflector like this
HTG Supply - Mini SunSoaker Reflector
I am leaning towards using a lazy susan bearing, fairly simple, and maybe an auto trans flex plate with a nylon pinion gear on the motor to provide gear reduction. Theory says the pinion gear should be harder, but we are only running 3 revolutions per HOUR of the flex plate, so it ought to be OK :-).
Just need to find out the DP and pressure angle of a chevy auto trans flexplate.