The Magic Candle

I got my vernier calipers and got an AA battery and proceded to do a daft thing when measuring the length of the cell. I had created a short because calipers being metal conduct. So this time I took a thin card and placed it at the base of the cell, and measured its total length, which was 50.6mm. I then measured the width of the card on its own which was 0.3mm and subtracted this from my previous measurement and got 50.3mm for the length of the cell.

Next I measured the protrusion of the + terminal which was 1.8mm, and subtracted this from the length making the cylinder 48.5mm.

Next I measured the cells diameter which was 14.1mm.
Then I measured the + terminal's diameter 5.5mm.

Next I went into TurboCad and drew in my construction lines to the origin. I set the preferences to have all dimensions in mm.

I made sure my construction lines were in the construction layer. Then I drew a vertical construction line 14.1mm from the origins vertical. And a horizontal 50.3mm from the origin. I ended up with:

Initialy it was intended that the lantern would be powered from 4 AA cells. 4 rechargeable cells offer 4.8 Volts@1200 mAh. 6 LEDs at full power consume 50 mAh each so 300mAh for the lot. Add 100mAh approx for IC and total current is 400ma giving 3 hours of light.

However, why create a battery enclosure to accomodate 4 cells, as this would make the enclosure more complicated to build than if only a single cell was to be used with a dc-dc step up to 5V for the IC? A nickel D-cell can hold up to 5Ah at 1.2 Volts. So at a maximum current of 5/1.2=3.3 times 400mA = 1.3A. 5/1.3=3.8 hours, so a bit more power as that obtained from 4 AA cells.

Re-dimensioning for a D cell, I came up with:

Battery enclosure

The metal tube in which the battery is to be enclosed can also serve as ground for the -ve terminal of the cell. Access to the battery as with a conventional torch via a screw cap. Either end of the tubing should be threaded so as to take a bezel.

With battery situated.

A spring is required to support and make connexion between -ve of battery and outer enclosure.

The PCB is grounded to the case. The +ve terminal to PCB via contact and spring.

Inner structure of plastic to support contact and spring. Inner plastic tubing to support battery.

I still haven't seen how and why you need an Arduino. All you've done so far can be done with a NE555 for a lot less money and a lot less effort. That is not to mention that the entire 555 circuit can be enclosed in one of those tubes/rods/candles/whatever.

Take some time to study the NE555 and you'll see that it might fit your needs a lot better than the Arduino, specially when comparing costs.

I am still not exactly sure what your question is, what you want help/collaboration on.

AlxDroidDev:
I still haven't seen how and why you need an Arduino. All you've done so far can be done with a NE555 for a lot less money and a lot less effort. That is not to mention that the entire 555 circuit can be enclosed in one of those tubes/rods/candles/whatever.

Take some time to study the NE555 and you'll see that it might fit your needs a lot better than the Arduino, specially when comparing costs.

The idea is to have 6 LEDs; red orange yellow green cyan blue. It's arguable that only red green blue are needed to make up any color in the spectrum. However, orange yellow cyan are pure wavelengths of that color.

Each LED is independantly controled to do pretty much anything you wish them to do. Such as flicker like a candle, flicker like a guttering lamp, flash, fade in and out, be of a particular colour, and have variation in brightness. Or have it set as colour temperature adjustable, so that it only puts out light where the spectrum is weakest.

The device is to be capable of being upgradable, for example, for receiving IR data from a remote control, or being triggered by a laser pointer. It is not intended in its pre upgraded form to produce a dazzling light. It's purpose is to replace ordinary candles. For example, you might keep a candle in a garden shed. Well you could keep this electric candle in the garden shed instead, reduced fire hazard. When you enter the shed or attic or cellar / place with no light or mains supply, you just point your keyring laser at it and on it comes. This means you don't have to stumble over piles of junk in the dark and risk injury in order to get to the far end shelf where the candle would traditionaly be.

So, depending on your requirements you need to choose what sketch is to be downloaded to the candle.

Now, I can think of dozens of permutations, applications and uses that this candle could be put to. However, I don't want to have to keep redesigning brand new enclosures every time a new upgrade comes along. And I want it to be backward compatible with the battery box, and other modules.

Supposing a new LED comes out that's an improvement on what's around today. I don't want to build a brand new system. I want to be able to pull out the LED module and replace it with the new, leaving everything else untouched.

fkeel:
I am still not exactly sure what your question is, what you want help/collaboration on.

So having provided a bit more back ground into the whys of the project, the scale of its ambition probably becomes more apparent.

The vision is to produce an open source enclosure construction system which is easy to assemble / dissasemble and looks aestheticaly pleasing. Provides robust build and is cheap.

This means, that everyone is free to take the construction blueprints and manufacture on a scale in their own community. To make it work however, there needs to be some agreed upon standards. For example, I have chosen a 50mm diameter for this project, but other projects may require smaller or larger diameters.

Current available off the peg enclosures are a real pest for tinkerers and often look shabby, unless you put lots of work into them.

So how is a thing like this built?

Help on applying the Open source GPL to its constuent parts.
Help on working out the threadings to be used.

Think of it like an open source software project except here the software will be gerber files, CNC milling files, dimension measurements and legible building instructions, as well as numerous sketches to run the product. The more people involved in creating this product, the better it will be. And we can find cheaper and cheaper ways to produce it, and at the same time be offering a GPL, perhaps the first GPL product aside from Arduino, the first GPL product for domestic purchase.

In the meantime I guess I'll just keep posting what I have come up with so far. I hope this helps. Thanks for your interest.

RamJam:
(...)Think of it like an open source software project except here the software will be gerber files, CNC milling files, dimension measurements and legible building instructions,(...)

FYI, that is called OSH = OpenSource Hardware.

I think this is a neat project and actually fits with something I've been working on. I look forward to reading more about it.

AlxDroidDev:

RamJam:
(...)Think of it like an open source software project except here the software will be gerber files, CNC milling files, dimension measurements and legible building instructions,(...)

FYI, that is called OSH = OpenSource Hardware.

With this in mind I have started checking out OpenSource Hardware. The Arduino board is also OpenSource Hardware. The following drawings show the complete assembly, and individual parts that make it up. There is enough information here to build this enclosure. Feel free to add improvements.

Drawing 8 shows the complete assembly:

The following photos show individual parts:







The following shows a list of parts:

Bt7cs:
I think this is a neat project and actually fits with something I've been working on. I look forward to reading more about it.

With the pictures in the previous post you can see how far I've got. Unfortunately, the cost of getting each part machined the traditional way would come to about £2500 !! This is the harbinger that is a major problem. I had naively assumed that progress had reduced costs. There is the 3d printer option such as Shapeways, however, they don't do brass or fine threads.

The drawings could do with extra refinment. In terms of a colaborative community project I don't know where to go from here.

Does anyone want an enclosure like this?
Do other people experience problems with enclosures for their projects?
Does anyone know how to get parts such as in the above made up at low cost?

Feel free to add your sketch or drawing ideas for components / building blocks to make up enclosures.

In the meantime I shall explore an idea for making the same type of cylindrical enclosure using off-the-peg tubing and using grub screws to fit the sections and end sections.

Suggestion: PVC pipe and connectors.

Something like this lets you connect 2 x pieces of 20mm pipe: Masters Home Improvement

Make those pieces of PVC pipe small enough and it's just going to extend.

There's an end cap for one end and then you just need the final piece for output.

Extendable, modular and more importantly for prototypes: darn cheap.

http://www.masters.com.au/product/900004873/pvc-valve-socket-20mm

This piece has external threading on the end.

Links are to local Aussie suppliers but America has even better access - check out "furniture grade PVC" as they have a lot of different connector types.

RamJam:
Each LED is independantly controled to do pretty much anything you wish them to do. Such as flicker like a candle, flicker like a guttering lamp, flash, fade in and out, be of a particular colour, and have variation in brightness. Or have it set as colour temperature adjustable, so that it only puts out light where the spectrum is weakest.

So, depending on your requirements you need to choose what sketch is to be downloaded to the candle.

Now, I can think of dozens of permutations, applications and uses that this candle could be put to. However, I don't want to have to keep redesigning brand new enclosures every time a new upgrade comes along. And I want it to be backward compatible with the battery box, and other modules.

I think for a user it isn't very practical to have to upload a new sketch each time they want the Magic Candle to do something different.
Maybe it would be better if in your sketch you can write all the different permutations or patterns that you like, and then you can add to the enclosure a couple of buttons (or it can even be made with you IR remote) to let the user cycle and chose the permutation they wish.

aarondc:
Something like this lets you connect 2 x pieces of 20mm pipe: Masters Home Improvement

Make those pieces of PVC pipe small enough and it's just going to extend.

There's an end cap for one end and then you just need the final piece for output.

Extendable, modular and more importantly for prototypes: darn cheap.

Hi aarondc. Thanks for that. So I checked the website and then googled acrylic tubing, and came up with plastock.co.ukwhich sold
Pitty it's only sold in 2 metre lengths. So I drew something based on those dimensions cut to a shorter length:

So I want everything to go into that width so as to be compatible with off the shelf candle holders.

This is a drawing of a D-cell;

Putting the tube over the cell approximates to this;
So there needs to be something to support the cell within the tube, idealy this would be a perfect fit but there wasn't one. Though clearplastictube.co.uk. They sold tubes in shorter lengths but not the blue one with that particular pipe wall thickness. with an inside dia of 34mm and outside dia of 40mm gives a 2.5mm gap which could be filled in with epoxy resin.


Next there needs to be a washer which can be cut from 5mm acrylic sheet and have a 10mm hole drilled in centre for the +ve terminal of the battery to poke through.

So I've ended up basicaly with this so far as an idea.

Unfortunately the 2.5mm gap left between the inner tube and outer tube is too narrow to insert a solid rod of reasonable diameter, which would be tapped at both ends with an M3 or M2.5 thread bore. Such a rod would need to be at least 6mm in diameter. One solution is to do away with the inner tube and replace it with an epoxy moulding like this:

The problem then becomes, how to make a moulding to form this part. The outside of the mould can be formed using the outer tube, while the inside can be formed using the outside diameter of a tube diameter which corresponds to the diameter of the cell, though slightly wider.
Next, there would need to be a base upon which the epoxy could set, such as a disk of plastic glued in place, though sufficiently brittle to remove after the resin has set. The inner tubing would have to be supported to occupy the centre. This could be done by glueing it to the disk.