Fred588 wrote:Duncan Edwards wrote:Fred588 wrote:If anyone here i perhaps you can answer a few questions. These have to do with s fairly knowledgeable about some very basic electronics related to a project I have in mind. The project has nothing whatsoever to do with quicksand.
1. What is the LOWEST output LED readily available?
2. Is it practical to connect 40 or so LEDs in a simple parallel circuit with a 12 (or 5) volt DC power supply.
3. Is there an easy way to use an LED to connect the two wires of a DC circuit. I say easy because the project would require 40 to 50 such connections.
I will be happy to discuss what all this is for with anyone who wants to know but will leave it out here because I suspect few will want to know.
You can get very low power LED's. Are you talking about just low light output?
Yes, it's not unusual to string lots of low power LED together. Christmas tree lights for example.
Just physically connecting the wires? On that one I have to answer no if you are asking that question. For me it's easy.
Love to know more about what you are doing because I suspect you could buy whatever you are after already assembled. There's lots of that sort of thing out there.
OK, here's all I left out the first time. I want the light output to be such that if the light is located a foot or more below the ceiling, the eye will easily see the light but NOT the ceiling, and without adding a shade behind each light. The issue with connections is this: The wire itself would be either two separate strands or paired strands pulled apart for each light. Obviously these would be insulated wire so each connection would require the insulation to be removed from a short segment of each wire, for each light. I presume each LED would be soldered in place, so that is 80 wire stripings and 80 solderings to make 40 lights.
This device would be powered using a 5v or 12v DC power supply, such as comes with a USB disk drive.
The application is as follows:
One room of the house is what I call the greenhouse. It is actually a room with a dirt floor and ordinary frame room. It is 12 by 24 and one long wall is almost entirely glass. It has been used for five years for growing the plants that decorate the sets and a few other places during the summer. The ceiling is slopped from a height of about 8 feet to about 12. For the future I plan to place a small table with four chairs near the center. I will then be able to serve dinner to up to four people, who will be surrounded by plants. [No carnivorous plants though] The plan is to suspend the proposed lights from the ceiling, mostly over the center 12 feet of the room, with the lights arranged randomly. The hope is that if the greenhouse lights are then turned off except for something just above the table (as in many fine restaurants) the 40 LED will give the illusion of the whole thing being outdoors under the sky (but without any bugs).
And to borrow a quite from Paul Harvey of years past.... "And now you have,...... the rest of the story."
In effect it could be thought of as the JungleLand Bar and Grill, for real.
So there are a few ways you can tackle this.
Things you will need:
-LEDs
-2 conductor wire (CL2)
-Dimmable LED driver/transformer
- magnetic low voltage (MLV), electronic low voltage (ELV) or incandescent/halogen dimmer switch
*This will need AC current and a dimmer to operate so consult an electrician*
1st: LED. For a rule of thumb, most LEDs are going to be 12vDC but individually, you can find them in 3v, 5v or higher depending on the power supply you wish to use but because 12v power supplies are more commonly found and easily integrated into DMX, I tend to use 12v. I would assume you are strictly looking for white or clear LEDs. As a rule, Light emitting diodes, by themselves, are not dimmable. You will need a driver/transformer for that (more on that later).
You can certainly run them in series, parallel or series/parallel but the most consistent will be a series circuit because voltage will be distributed evenly across all diodes.
You can use 2 conductor wire 18-16 gauge (black would be ideal in this circumstance). A thing to note: these are still diodes so polarity matters. The LEDs should be marked negative to positive bias by either a red or black pigtail OR one tine will be longer than the other. They will be wired in this fashion.
A thing to consider is amperage. It’s important to see what the draw will be before buying your transformer or you will have flicker but no worries, 40 LEDs shouldn’t consume too much. On the average, 3 LEDs draw about 20 milliAmps. These drivers are meant to push LED uplighting and cabinet lights of 100 or more LEDs so you will not need much.
For dimming any incandescent dimmer should work. This will wire directly to the LED driver. The LED driver is in charge of keeping the circuit stable even when AC current is dropped by the dimmer so the LEDs will not flicker.
It’s a bit more involved and this is more of a permanent installation.
With resistors, it is possible to have a similar dimming effect on LEDs of a simple 12v circuit but this takes some math, trial and error and some more soldering.