Step 3: Build the LED circuit (with tilt switch)

A string of LEDs... (pictures 1, 2, 3)
The six leds in the tube are connected parallel (all the led's plus-sides are connected, and all the minus-sides too). Use stranded (supple) wire to connect the leds, so they fit into the tube nicely later on. To connect the leds to eachother, I soldered 6 strings of wire pigtail, and then soldered the pigtails onto the led's leads. See picture 3 on how to do that. If it's not clear to you then, have a look here for a more detailed explanation...

Blinking LED circuit (pics 4 through 8)
The circuit that makes the leds blink (picture 4) is a very basic circuit around a 555 timer. This is not the most efficient way to do the job, because the 555 timer consumes a fair amount of energy just to stay alive. I used this scheme just because I had the soldered pcb lying around (it is a remnant from a previous I'ble I made). On the pcb a switch was soldered already. I replaced this switch with a roller ball switch.

This circuit should be turned on when the Sound Tube is set vertically, with the speaker-side up. A roller ball switch (or a tilt switch) takes care of this. 
  • Solder the components onto a pre-etched pcb. Cut the copper strips where marked with an X in the drawing (picture 5).
  • Solder pieces of supple wire of about 8 cm (3") to the roller ball switch' leads.
  • Eventually, solder the string of six leds to the pcb and test the circuit.
I tried to make a roller ball switch myself, but the attempt failed miserably. See pictures 10 through 15. None of these switches work :-s

Powering the circuits
The voicerecorder and the led-blinking circuit are powered by the same 9 Volt battery.
I made a seperate, small pcb on which the battery's leads and a switch are mounted. The powerleads to and from the voicerecorder and led-blinking circuit are all connected to this pcb.
The switch is used only to shut down the Sound Tube completely.

Optional (picture 9): Leds fading in and out
What I really wanted was an array of leds that fades in and out. I spend hours trying different kinds of circuits, but none of them worked the way I wanted to. Making a led fade in was not so hard, but letting a led fade in and out without a microcontroller is truly a tricky task to accomplish...
Eventually, I got help from Jan Leisink, probably the best science teacher in The Netherlands. He came up with a circuit that almost worked the way I was looking for. After some tweaking, I got it right. Unfortunately, that was after the Epilog Challenge deadline, so that's why it's not in the Sound Tube I made.

Now, if you build the circuit in pic 9, chances are that it will not work just as you expected: The way the leds fade in and out depends strongly on the values / specs of four components in the lower left side of the circuit: The leds, the transistor, the capacitor and resistors. To make tweaking more easy, I put a variable resistor in the circuit. Adjusting it's value influences the way the leds fade in and out.

A big advantage of this fade-in fade-out circuit is that it is much more efficient in energy than the 555-timer circuit. So using this circuit will make the 9V battery last a fair bit longer. Give it a try, if you like.
<p>An alternative circuit is a straightforward a-stable using the 7555 (actually, you gave me that idea, used it for a blfnar). A very nice setup is to put 6 LED's anti-parallel and put a decent sized capacitor in series. if you then also put a resistor parallel *) to the LED's it ensures the full (dis)charge of the cap. Whenever the 7555 flips, 3 LED's will flash on, fade out. Very nice effect.</p><p>*) you best size the resistor that multiplied by the value of the series capacitor is roughly the same as the R*C of the 7555.</p>
<p>Sounds interesting... What do you mean by &quot;anti-parallel&quot;? Could you draw a circuit to explain?</p>
<p>See image, sorry for the quality, draw in yoh-draw ;-)</p><p>The idea is if 3 goes high, current rushes through the top 3 LEDs. As the C charges, the current will fade away. The LEDs will be off under about 1.6 V at which point the resistor will ensure the capacitor is fully charged. When the 3 goes low, the capacitor discharges over the bottom 3 LEDs and again the resistor will ensure a full discharge.</p><p>The resistor is needed if that last 1.5 V is really needed. It is when powering from a 3V source. If you stick with say a 9 V battery, no need at all as the C will charge to 7.5V (battery minus LED forward voltage).</p><p>I would recommend a small current limiting resistor in series with the C, though the 7555 can be mishandled somewhat.</p>
<p>Cool! All clear, thanks!</p>
You, my friend, are a true genius!
Did you notice I made the video on Monster Marit's 11th birthday?
my jar idea: <br><br>you open the lid of an empty jar (empty is signalled by LEDs or lack thereof) and can then record. This makes the jar full. (signal by LEDs, etc)<br><br>You listen to a recording by opening the jar. <br><br>You empty the jar by turning it over and pouring the sound out. A mercury switch of some sort?<br><br>The only thing I'm not sure about is when to start recording again after emptying. As soon as you turn the jar back upright (makes it unobvious how to leave the jar empty), or should one have to close and open the lid again (awkward to empty the jar and then leave a new message)? :)<br><br>With some bonus LEDs and a counter, could the age of the message be indicated? (it'd be nice to know if there is something new, or if it's the same as the last time you saw the jar... :)
Possibly, It would need to have the display (You can find pre-built analog ones at Radio Shack or any hobby shop) and a switch to start the timer (something like a tilt-switch or copper foil on the lid depending on how and when you want the timer to start.)<br><br>Also, have you thought of using an arduino board to control it all. I bought mine in July and it seems like it would work great for something like this.
OR! You could be boring and old fashioned and have a jar full of paper and a pencil that you leave PAPER NOTES in that people TAKE OUT AND READ! and a small flag to signal! wait a minute.... did I just describe a mailbox? -.-
ZAKDOEK... :D<br>Grappig idee, leuk gemaakt !
This is awesome! I have one of those voice recorder things and my fiance and I always leave notes to each other on it. This is way more fun and stylish to have as a decorative piece rather than an exposed board with a bunch of wires hanging out. Great idea!
Misschien moet je wel voor een volgend project even een boek met citaten doorbladeren. &quot;Zakdoek&quot; is niet meteen een uitspaak waarmee je de geschiedenisboeken gaat halen :P
:) Ik bedacht gisteren dat &quot;vloerbedekking&quot; een veel beter woord was geweest. Het fameuze &quot;Hello world&quot; heb ik overwogen, maar vond ik uiteindelijk te afgezaagd...
dutch people are the best!
now you don`t need paper in a bottle to write an sos mesage in an island
Van harte gefeliciteerd!
Dank je! Waarmee precies?<br><br>Y.
Met het maken van zo'n awesome gadget!<br>En ook misschien een beetje omdat dat voorkomt in het filmpje op 0:33.. :D
Ah, xnappem! Beetje traag van begrip, vanavond, lange dag gehad :-) thnx!
I LOVE this idea and also think the jar would be awesome. Knowing that I am, at best, a novice among novices, I wonder if you could use a storage jar with a lid that snaps on instead of twists, and then have different contact points for play &amp; record. Twist left &amp; open to record, twist right and open to play.
Could you put some kind of mesh inside so the guts aren't shown when you open the lid?
Maybe the cloth that is used for speaker-fronts? The mesh shouldn't push down the micro-switches, but i guess that ca be avoided without too much trouble...
For some reason I'm unable to reply to the thread above, but you could totally make it a sound jar (just one lid) even without an Arduino, with a smart application of logic gates (using some latching to store the previous state) and maybe some more caps to &quot;debounce&quot; the opening of the lid. I'll see if I can come up with a simple circuit that'd do so, because and Arduino is really overkill for this kind of thing. Not that that's a bad thing...Instructables is mostly about overkill anyway :P
I agree that the power of an Arduino is overkill to the task. I did fiddle with a latch-type flip flop, but I never got anything out of it that actually worked. I would greatly appreciate if you can come up with something to go along with!<br><br>Y.
Nee. :-)
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I like this a lot. Very cool.
Thanks! Do you think the use of an Arduino can help to make a &quot;one lid sound jar&quot;?
Yup. You would just use a photocell and change the state on light/dark transitions. So the first time you open it, it would record and then when you close it, the state would change. The next time you open it, it would playback. You can control the sound module by replacing the switches with relays perhaps.
A message in a bottle! What a fun way to leave a message for someone.
Thanks! It works really well, much better than I expected! The whole family here loves the little machine. I think the act of actually opening something to hear what's in there for you makes it fun, and the blinking leds are a good indicator of the message being present.
I might have an idea for one way to manage having only one lid on the jar.<br><br>Think of like a seasoning jar or something. Many have a lid with two ways to open it; one side for precision pouring, and the other for pouring larger amounts of seasoning. So just use one side for recording, and the other for playback. If you had a lid like that, you could probably whip something together.<br><br>Technically it is one lid, but it still isn't what exactly what you're looking for. Or, if you want something else, I might have another idea.<br><br>If you manage to mount a record button on the outside of the jar, and somehow tweak the system to alternate between record and play modes, you could get that to work. Or you could even use a switch to toggle record and playback.<br><br>I don't know if either idea is exactly in line with what you want, but at least you have somewhere to jump off of for now.
I considered the record-button on the outside, too. A flip-flop latch (or just an entire Arduino) could toggle between record an play modes. I haven't tried to make it work, because I think it makes the use more complex and less intuitive.<br><br>I also considered the use of an Arduino to keep track of opening and closing of the lid. I have little experience in digital electronics, but I guess it can be done...
I wonder if you could used the voice recorder circuit from those recordable greeting cards<br><br>
Yes you can! It's exactly THE Same circuit, but THE quality of recording and playback is less.
Sorry for the strange use capitals... I wrote that comment on an iPad with apparently peculiar language settings...
Nice, this is really cool!
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Perfect for a house full of folk who are in-and-out.

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Bio: Also have a look at member Monster-Marit. She Rocks (I'm a bit prejudiced, though :-))
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