Just changed it to 2.5s in and 12.8s out, by adding back a single resistor.
However, the attached .pdf won't reflect that, but I'll update it tomorrow. Apart from what's in the .pdf, you'll need a 22k resistor:
http://www.gmelectronic.com/ru-22k-0207-0-25w-5-p119-066



The exact position of the magnets, relative to the switch, depends on the strength of the respective magnetic fields, but the reed won't need to be smack dab in the middle.
Different strength magnets can be used and while I have to work the thought a bit, either the lid-magnet can close toward a bit of iron or another magnet, which may then be usable for bias as well... I need to think it through.

If you want to use magnets for closing, the one I linked from GM (AlNiCo magnet) won't do, they're much too weak. They do have a set of 10 magnets from Velleman but the latter describes them as "rating: N35~N45", which is sort of nonsense, as the Nnn describes a set of parameters of a magnet (like strength and high temperature limit) and they don't have such loose specs.

Besides, although neodymium magnets are strong compared to AlNiCo, N35 is about as weak as they come,while N45 is about "medium" - really strong neo's are N5n.
They'd all be OK for your box though, but they're eur 5.07 for 10 at GM, so if you have a cheap thrift store locally, you might be able to pick up a few magnets with attached fridge ugliness much cheaper, or perhaps one of the weighted steel wires, that uses small neo's for attaching postcards and photos to the wire - the ones I've seen had 8..10 magnets in such a "set" - just make sure that you get the strong neodymium types (if they look small for the purpose, they probably are neo's) - there's and endless amount of cheap stuff and toys using them.

The reason to go for neo's is to get the dimension down while keeping a good strength - if you stand a cylindrical magnet on the edge on eg. a table and tip the table a little, a strong magnet will try to only roll a path of east-west (if polarized along its length, i.e. N-S on the plane sides) - that's how strong they are.


I didn't put wire on the list, as you'll likely be able to scoop some up - even a short piece of CAT5 "Ethernet" cable will give you plenty.

The sponge I left out as well, no extreme need for it, as you can use a moist tissue paper or a moist piece of cotton cloth. The sponges are made of cellulose (organic) and must be moist in use, or they won't last long - I use distilled water on them, to make them live longer and stay softer - they're pretty stiff when dry, no matter the water.
By moist I don't mean wet - the moisture only has the purpose of protecting the sponge by a ~100°C vapor barrier. If wet, they'll cool the tip (and shock it a bit) - not good.

You can get cellulose sponges made for several other purposes. Some (most?) sponges for wiping a black board is that type and the cheapest I've found are some oval shaped 1,0..1,5cm thick sponges used for cleaning kitchen and bath - just read on the packet what it's made from. They're a light yellow-beige-ish color.

A plastic foam sponge would die screaming and hurt your soldering tip as well.


BTW. do you shop in GM's physical shop or order online?

Here's the .pdf View attachment 84848

Thank you very much Soeren!
The timing sounds great!

And the PDF is outstanding! I understand everything well and the schematics are so well made, thank you so much!
I have just two questions:

Concerning the parts, do they have + and - side or are the two wires identical? I can see there are some + signs every now and then and I am not sure if it has something to do with the positive and negative poles (I am thinking that they are just CAD symbols). I know that LEDs have + and - and that one is longer and other shorter, but I am not sure if it is the same with the resistors and capacitors for example and if I can find in the schematics on how to connect them in this way.

And the numbers above the schematic and the letters on the side, what do they mean please?

"Regretfully, I did not get around to show how the reed switch and the LEDs should be wired, but maybe tomorrow." Please, if I may ask you for this, it would help a great deal!

I ordered all the parts online and I will be picking them up in the physical shop. I checked if they are all availible in the physical shop in my town (Prague) and they were all there, except for the capacitors. I checked the alternatives and the closest capacitors availible were these, so I took them instead: http://www.gme.cz/cea-470u-25v-vis-asm-10x18-p002-096
They are pretty much the same, except these are made for 25 V (and I guess they will be slightly bigger) - I hope it is not a problem.

Don't worry about the closing of the lid with the reed magnets. I was just thinking if it would work that way, but I can easily buy two neodymium magnets (I ordered 4 of these just to be sure - might use the other two for the reed switch as well http://unimagnet.cz/154-KT-03-01-N.html and 2 of these (these might be better for the switch?) http://unimagnet.cz/758-KT-01-01-N.html) and place them in a different part of the box solely for the purpose of closing the box.

I bought a thin, single core wire from the GME shop. I didn't went for the sponge and the solderless testing board though, I hope I haven't made a mistake. I will use the tissue papers for cleaning the tip.
I will also buy the solder "gun" today.

So everything will be prepared soon! I will go to a workshop tomorrow to finish and make the wood+plexiglass part of the box. I will make the box 10 cm in lenght, 5,5 cm wide and 4 cm deep. I hope it will be enough to fit all the things in there (including the the gift itself ).
And I will have the time to prepare the electronic part ideally in friday or during the weekend. Oh boy, I am so excited and nervous at the same time! It is like if I would have some exams ahead.. :-D There are so much things to do apart from the electronics project. I think my head will explode :-D

Thank you so much again for helping me out with this Soeren, I don't know what I would do without you!

 

Oh and concerning the light intensity, will there be a chance to dim the LEDs a little bit or are the new blue LEDs you have chosen ok? I have no idea how intense they are in full light, but I guess these blue are much better in this than the crystal clear blue I bought earlier. Also I wanted to sand them with a fine sandpaper to diffuse the light a little bit, so that might make the light more pleasant too.

Also (this is really the last question ) last thing about the matrix board - should I cut some specific sized piece and solder parts onto it or first solder all the parts on the sheet and then cut the excess material?

What troubles me is how to integrate the reed switch into the box. I understand that there needs to be magnet bellow and above the switch (integrated in the lid), but how close to the magnets must the switch be? I guess it depends on how strong they are right? The problem here is with the "fake" bottom. In order to make it removable, I want to make it in the way that you can push it from the side and slide it off (so you can change batteries etc.). But the plexiglass piece for the fake bottom will create a kind of split - bellow the plexiglass, there will be the circuit, but where should be the reed switch, if it should react to the lid? I thought I will put the reed switch higher and connect it to the circuit with wires, but how would I guide them through the plexiglass (which will basically cut the box in half)? What I thought is that the switch would be under the plexiglass in the wood part, bellow it a magnet and I would need to hope that the remaining 2 - 2,5 cm will not be too much and that the force of the magnet from the lid will open the circuit.

 

It will either be unipolar or omnipolar for this purpose, but perhaps it has a type number/name in tiny letters and numbers that can be fed into one of the SMD databases, maybe even a logo to reveal the manufacturer.

The good news is that the entire assembly in the picture can be purchased for ~$7, so I won't be doing any board-level soldering.

I completely agree that's a hall sensor. Folks referred to it as a reed switch but I think that was just them not knowing the difference.

 

I understand everything well [...] I have just two questions:

That would be almost everything then

Concerning the parts, do they have + and - side or are the two wires identical? I can see there are some + signs every now and then and I am not sure if it has something to do with the positive and negative poles (I am thinking that they are just CAD symbols). I know that LEDs have + and - and that one is longer and other shorter, but I am not sure if it is the same with the resistors and capacitors for example and if I can find in the schematics on how to connect them in this way.

The resistors and the reed switch are not polarized, but the rest must go in the right way. The transistor should go in as shown, the capacitors will have the negative terminal directly on the metal case and positive goes through a black "rubber" seal - negative goes to ground.
The LEDs will have a flat side on the lower "ring" where the negative terminal is and the longest wire is the positive, which goes to +6V (via a wire).
The batteries must be polarized correctly as well (obviously), but the holders take care of that.

And the numbers above the schematic and the letters on the side, what do they mean please?

They're just to make it easier for you to break the right connections - it's very easy to make mistakes, if you don't have a way to reference the position of each break.

"Regretfully, I did not get around to show how the reed switch and the LEDs should be wired, but maybe tomorrow." Please, if I may ask you for this, it would help a great deal!

Yes, see attached .pdf

I ordered all the parts online and I will be picking them up in the physical shop. I checked if they are all availible in the physical shop in my town (Prague) and they were all there, except for the capacitors. I checked the alternatives and the closest capacitors availible were these, so I took them instead: http://www.gme.cz/cea-470u-25v-vis-asm-10x18-p002-096
They are pretty much the same, except these are made for 25 V (and I guess they will be slightly bigger) - I hope it is not a problem.

They're just 2mm larger in diameter, but the length is the same, so they'll do fine.

Don't worry about the closing of the lid with the reed magnets. I was just thinking if it would work that way, but I can easily buy two neodymium magnets (I ordered 4 of these just to be sure - might use the other two for the reed switch as well http://unimagnet.cz/154-KT-03-01-N.html and 2 of these (these might be better for the switch?) http://unimagnet.cz/758-KT-01-01-N.html) and place them in a different part of the box solely for the purpose of closing the box.

You'll have to experiment with it when the box is built, too many unknown variables now, but I have included a photo of a small box with magnet closure which has just about the right strength for this box.
The KT-01-01-N might be way too tiny and I'm not too sure about the 3mm version - I'd rather bet on a small diameter but longer/thicker magnet, due to how the reed is best actuated (N-S axis of magnet should be in parallel with the length axis of the reed.

I bought a thin, single core wire from the GME shop. I didn't went for the sponge and the solderless testing board though, I hope I haven't made a mistake. I will use the tissue papers for cleaning the tip.
I will also buy the solder "gun" today.

The single core wire is fine for the jumpers, but it's easier to work with multicore wire, as it's way more flexible - if you can't find any (you'll need less than 1m in all) in some discarded electronics, the single core will do, as long as it is not flexed back and forth in use.

You don't need the solderless board for this - it's if you want to experiment further than this particular project.

Moist tissue paper is OK for a small job like this - when I shot the photos in the .pdf, I used a moist single-use kitchen-cloth, as my sponge had magically gone AWOL on me. Whatever keeps your tip clean.
You only wipe right before soldering. When a connection is made, the solder on the tip helps protect the tip from oxidation.

It's a soldering iron A soldering gun is a (surprise) gun shaped and clumsy thing that a plumber may use.

So everything will be prepared soon! I will go to a workshop tomorrow to finish and make the wood+plexiglass part of the box. I will make the box 10 cm in lenght, 5,5 cm wide and 4 cm deep. I hope it will be enough to fit all the things in there (including the the gift itself ).
And I will have the time to prepare the electronic part ideally in friday or during the weekend. Oh boy, I am so excited and nervous at the same time! It is like if I would have some exams ahead.. :-D There are so much things to do apart from the electronics project. I think my head will explode :-D

The 10cm better be the inside measure, or we'll have to make another battery holder (or modify one to take two CR2032 stacked.
Nervous? Is it a circular gift that demands a vocal response from her perhaps

Thank you so much again for helping me out with this Soeren, I don't know what I would do without you!

[/QUOTE]
You're welcome and if all else fails, a box of chocolate or a bottle of scotch will likely be a good substitute (whatever floats her boat ).
When you have the components, please check if they are the right ones exactly and tell me if they're not, so we can see if changes are needed.

Latest layout, I won't get it finished until tomorrow.

The .pdf
View attachment 84920

And here's how the reed switch works with a single magnet - we reverse this action with the bias magnet.

 

Oh, won't edit, so let's try that again...

Layout

.pdf View attachment LED_Fade_Up_Down_Reed-LED.pdf
View attachment LED_Fade_Up_Down_Reed-LED.pdf
Not sure if the .pdf link works, I can download it from "My attachments", but not from post
If it doesn 't work, I'll try another way tomorrow.

Switching a reed

 

Hi Soeren, thank you so much for your answers! I am writing, dead tired after preparing all the wood (I was working on it 6 hours in a row).. I will check everything you wrote in detail tomorrow. I have everything set up, bought the components today, made the box (it is not glued together yet, I will wait for the circuit and glue it after it will be finished ) and I've even created an intricate design to hold the reed switch - I improvised it in the workshop (I improvised almost everything actually.. :-D), it was really crazy. My head still hurts from all the brainstorming. :-D Not sure if it will work, but I really hope it will. I will describe everything tomorrow and respond to your answers.

So only the circuit challenge now awaits! And when this is done, all is done!! Can't wait! :-D I will do it! I can do it! I have to do it! :-D (Sorry for my crazy evening talk :-D )

 

Hi,

Oh and concerning the light intensity, will there be a chance to dim the LEDs a little bit or are the new blue LEDs you have chosen ok? I have no idea how intense they are in full light, but I guess these blue are much better in this than the crystal clear blue I bought earlier. Also I wanted to sand them with a fine sandpaper to diffuse the light a little bit, so that might make the light more pleasant too.

The diffused LED's are not as "shrill" as the clear ones, but if needed they can be dimmed of course.

Also (this is really the last question ) last thing about the matrix board - should I cut some specific sized piece and solder parts onto it or first solder all the parts on the sheet and then cut the excess material?

You need to cut the board before you build on it.
Score the next row of holes a couple of times with a knife and a ruler and break it over a sharp edge of a table or similar.

What troubles me is how to integrate the reed switch into the box. I understand that there needs to be magnet bellow and above the switch (integrated in the lid), but how close to the magnets must the switch be? I guess it depends on how strong they are right?

Yes, you need to test this with the specific reed you have and the magnets.
Just to be clear on this, the magnets doesn't have to be on opposite sides of the reed. It just needs to have a field strong enough to positively engage the reed and then another field of opposite polarity that is strong enough to cancel some of this field, to get the resultant field under the holding force of the reed - difficult to calculate (parameters missing), but very easy to test physically.

I'd guess that you haven't got a multimeter?
A 5V-9V battery with a 470 Ohm current limiting resistor and an LED in series with the reed will tell you when the reed is engaged.

The problem here is with the "fake" bottom. In order to make it removable, I want to make it in the way that you can push it from the side and slide it off (so you can change batteries etc.). But the plexiglass piece for the fake bottom will create a kind of split - bellow the plexiglass, there will be the circuit, but where should be the reed switch, if it should react to the lid? I thought I will put the reed switch higher and connect it to the circuit with wires, but how would I guide them through the plexiglass (which will basically cut the box in half)? What I thought is that the switch would be under the plexiglass in the wood part, bellow it a magnet and I would need to hope that the remaining 2 - 2,5 cm will not be too much and that the force of the magnet from the lid will open the circuit.

Not knowing the height of the sides, I'd either drill a hole from the bottom to a few mm from the top and mount the reed vertically. That way it's aligned with the magnets if drilled holes are used for them as well.
Otherwise and if the height won't allow this, I'd route a narrow channel for the reed (or make a channel by assembling 3 flat pieces. That way the magnets should best be mounted in a rectangular hole.

BTW. you mentioned covering the plexiglass with black glue... It'll be nicer and easier to just paint it - from the other side, paint looks really nice and very deep.

Here's the newest file - I got the board a bit smaller
View attachment LED_FAde_On-Off_3.pdf

 

Hi!
So much stuff to do! I didn't find a time to get around to making the circuit yet! I am not even sure if I can do it tomorrow.. I think my only shot will be on sunday or during monday..
Thank you very much for all the updates and your answers to my questions!

I made series of holes with a drill on the side piece of the box, so the whole reed switch can fit in there, horizontally. There is a small depression beneath the holes, where a small neodymium magnet can fit (I have couple of small ones). There are also gaps for the wires, which I made with very thin saw. There are also two holes in the fake plexiglass bottom, so the two wires from the switch can go through it to the circuit board bellow (I have to expand the holes in the plexiglass until the very edge of it, because I haven't thought about the situation when I will want to pull the bottom out - I would need to tore the wires off, so I need to work on that a little bit ). I wanted to paint black with the glue the actual matrix board, because it has this brown color that might be visible through plexiglass, which will be transparent/translucent. Not sure if this will be an issue though.

It is great that the circuit board is now smaller! The 10 cm is actually outside of the box. I think inside, it will be about 9 cm and 5 cm wide. Thank you for that!

I don't have multimeter unfortunately. :-(

I will test the reed switch after finishing the whole circuit I guess, that will be the best way to see if it works or not. I am hoping that the small magnets I have will be enough. They are quite strong, so I hope they won't be actually too much for the switch. So the two magnets need to attract or repel each other in order to open or close the switch? I guess that is all for testing. Oh, I see you wrote it here: "N-S axis of magnet should be in parallel with the length axis of the reed". And I can see many more informations in the attached PDF. Not sure if I understand it yet, but I will surely decipher it later on (especially in the field test). )

Oh, I am so excited! I am really looking foward to do this on sunday. Part of me is afraid that it will not as smooth as I imagine it, but I am determined to do the best I can to finish this thing.

I can't tell you how much I appreciate your help with all this - I would never make this happen without you, never. You are the best! Rest assured I will fully credit you when I will giving the gift.

I will keep you updated! But sunday is the day I will do this! I will reserve the whole day for it.

 

Hi,

I wanted to paint black with the glue the actual matrix board, because it has this brown color that might be visible through plexiglass, which will be transparent/translucent. Not sure if this will be an issue though.

When the board is finished and working, just give it a layer or two of flat black paint, that will make it the least visible (if you have a hobby shop of sorts, they'll most likely have small bottles of flat black paint relatively cheap) - or put a layer of dark paper between the board and the plexi.

[...] I hope they won't be actually too much for the switch.

I won't risk anything betting that they aren't
The magnets used in the animated gif-file was neodymiums as well and while that particular reed switch wasn't very sensitive (cheap Chinese product), the magnets were both 3mm thick and one was 5mm in diameter and the other 6mm in diameter (and hard to pry apart).

So the two magnets need to attract or repel each other in order to open or close the switch? I guess that is all for testing. Oh, I see you wrote it here: "N-S axis of magnet should be in parallel with the length axis of the reed". And I can see many more informations in the attached PDF. Not sure if I understand it yet, but I will surely decipher it later on (especially in the field test). )

Here's an illustration, not exactly Rembrandt, but I'm sure you get it anyway

Oh, I am so excited! I am really looking foward to do this on sunday. Part of me is afraid that it will not as smooth as I imagine it, but I am determined to do the best I can to finish this thing.

I'm sure it'll work out.

Rest assured I will fully credit you when I will giving the gift.

Nah, don't blame it on me
You should take all the credit - always good to build up a positive account with ones sweetheart and it sure helps if/when you screw up someday

I will keep you updated! But sunday is the day I will do this! I will reserve the whole day for it.

When it's done and you're not too stressed out, it would be nice if you could post a photo of the finished box - I'm a bit curious about how it turned out

 

Hi,


When the board is finished and working, just give it a layer or two of flat black paint, that will make it the least visible (if you have a hobby shop of sorts, they'll most likely have small bottles of flat black paint relatively cheap) - or put a layer of dark paper between the board and the plexi.



I won't risk anything betting that they aren't
The magnets used in the animated gif-file was neodymiums as well and while that particular reed switch wasn't very sensitive (cheap Chinese product), the magnets were both 3mm thick and one was 5mm in diameter and the other 6mm in diameter (and hard to pry apart).



Here's an illustration, not exactly Rembrandt, but I'm sure you get it anyway

I'm sure it'll work out.



Nah, don't blame it on me
You should take all the credit - always good to build up a positive account with ones sweetheart and it sure helps if/when you screw up someday



When it's done and you're not too stressed out, it would be nice if you could post a photo of the finished box - I'm a bit curious about how it turned out

Ok, I will give it a try. I also thought about a black, really thick permanent marker, that could also do the job.

Thank you for the illustration, I get it now! For some reason, I thought the magnets need to be on their flat side (exactly like when they stick together), but they are actually on their side like that.. Ok, good to know!

:-D Don't worry, if I will mess it up, the blame won't be on you. :-D I will definitely send you a picture if it turns out nicely!