Step 4: Does it Work?

Insert the battery with the positive side up, and press the button, and you should have a functioning key ring light! As I mentioned, this design is an experimental prototype only - if I produced these on mass, I would probably change a few things. Firstly, I would make the board smaller still (for cost), and put the name/contact details on the reverse of the board. I might also change the CR2032 cell to a CR2016 as this is thinner, and cut a hole in the board to mount it inline. This would make the whole thing very thin indeed. I might even encapsulate the board in clear heat shrink tubing or the like, to stop it shorting out on keys whilst in the pocket.

Do you think that you can handle an even more advanced design? If so, read on to see how the "autodialing card" works ...
amazing idea you should patent it thank you
hi you have the beginning of the idea , billions of business card are printed on paper each year but something is missing here to make it a world wide market but please free to contact me ( I am living in France ) I just has a wondurfull idea but I am not into electronics ( but I do have tech knowledge as a end user) <br>Richard <br>+336 25 21 21 21 send me a sms and will return you a valid email
Make: posted a video about a year ago of how you can make your own custom PCB's using the photographic method http://www.youtube.com/watch?v=tWnfnt2rNO0<br><br>-TheWaddleWaaddle
The Autodialling Business Card is just an insanely cool idea!!!<br><br>Thanks for sharing.
If the chip can be programmed to say something like "I am diabetic" with brief first aid instructions or an emergency number either spoken or programmed to dial, I could see this as a great emergency aid.
i think the problem is that pic chips have a couple of kilobytes of memory if that. so generating more complex sounds would use a lot more memory, might have to have it external or something.<br />
Aren't there those cards where you can save a message and when you open them it plays the message? They aren't that expensive, and you could have the whole thing independent from the PIC itself.
Actually, as a single guy who dates a lot, this would have other uses ! :) Hey... Marvellous instructable. Thanks !!
Truly and utterly baffled by the ingenuity of your design.<br>In one word, fascinating.
You should do a site like cardnetics! You have great ideas!
im thinkin for a cheap way to do that thing wid a usb in it is to buy 64mb flash drives in bulk put ur info on it then crack the case and put it on the card if u wanna or just get them custom engraved for a bit more
They arn't thin enough<br>And i dont think that they make 64 mb anymore
What about using a reed switch so when you put the card near the magnet in the phone receiver it dials (semi-)automatically?
Great 'ible., but I think someone will write an &quot;app&quot; they can: email, bluetooth or otherwise transmit to a smart mobile.<br /> <br />
&nbsp;well how about a credit card form factor usb key, such that the recipient can plug it into their computer? &nbsp;A mobile app would pop up that allows the user to send an email to a predefined address, and connect a voip call over pc?<br /> <br />
This is great, because if I was a potential client, I'd be tempted to call you just to see it work. :o&nbsp; I imagine you sometimes get callers who introduce themselves&nbsp;as &quot;That is AWESOME&quot;<br />
&nbsp;I've&nbsp;subscribed to you. Your&nbsp;awesome!&nbsp;&nbsp;
your IQ must be 250 <div id="FLASH_MESSAGE" style="display: none;">&nbsp;</div>
I&nbsp;enjoy this comment thoroughly.&nbsp; <br />
does this actually dial numbers??
Ha! thats awesome. Just make one for everyone you know, file them and you never have to look up a phone number again!!!
for the dialer try to use a transistor to amplify the signal from the microcontroller and use a single 3v cell... i would recommend a 2N3904 as it is so common; connect the base to where the piezo + used to be, the emitter to the piezo +, and the collector to the + of the battery. i didnt see a schematic so it might be the other way around, but this should work.
It's not really the current that's needed but the voltage ands we are already feeding in close to the maximum voltage we have - piezos draw almost no current, so the only way to increase the audio output is to increase the voltage - either by using another cell or by a step-up circuit.
in my understanding, a transistor here will amplify the voltage however, if not, then a simple smt inductor should also work. original design was pretty clever about this stuff though
A transistor can only amplify a voltage up to the level of the power supply. Here we are essentially feeding the piezo with a 3V (or 6V with two cells) square wave already. Didn't go for the inductor idea as it was hard to keep a thin card with an inductor-based step-up supply and it was simpler and cheaper just to add another cell. Certainly if you were able to do this however, the piezo would be much louder and more able to put out a decent DTMF signal - piezos can often be driven with up to 50V or more to increase the volume.
well that is true. Your way works great, no complaints there. Nice work
very clever
Three words "Rejection Hot line"
you need to patet it so no one copies
This is so badass. Thank you so much for doing a tutorial, it's really neat!
On the card: If you have any problems press here. *sets the number to 911*
Perhaps a small hole on the back of the card, aligned with the hole on the piezo disc, would permit better conduction of sound from the card.
But it wouldn't look nearly as cool, now would it?
Well, you can't really see the hole in the corner, which I suppose is the point. But, you do want it to work as well!
But there must be some way to make it work better, yet still look as cool.... Hmmmmm.... I wonder.... I've got it! Turn it into a robot flying death-ray UFO machine, and put the speaker in its mouth! Perfect!
Hmmm, I think the goal of this project is to win clients, not annihilate them from the face of the Earth.
But what if you could do BOTH!!??!!??
I like your thinking! What if the speaker instead said things like "BUY MY PRODUCTS OR BE ANNIHILATED!". And if they didn't comply, - BOOM! Destruction! Lasers! Cool sound effects! Hmm...
Now that would be one business card I couldn't help but take from the little dispenser thingy.
I made one of these, and use a really fine, plastic screen over the ring, which concealed it, and still let through the sound.
thats a lot of work for a business card
insane and absolutly amazing =oO. would love to have a go at that but i wouldnt have the 1st idea when it came to programing it, would like to have seen some back and side pics. top job dude<br/>
Yeah - must take a side pic - it really just looks like a strip of white that is 3.2mm thick. Back I didn't put on because it is just plain white!
Hi Tom, The company I work for could make these easily. In fact I would be interested in helping you design the least expensive and thinnest card. I am thinking of making a bunch for the CES show in Vegas as a give-away. We would injection mold these. Of course I would give you all the glory. Smart design!
Go for it, but don't underestimate the amount of work this design still needs if you really want to make it work properly as stated in the article - getting accurate DTMF recognition from an audio system just a couple of millimeters in thickness is not trivial, and will require quite a bit more development work. Good luck, though and look forward to seeing what you come up with!
by-the-way contact me at: fkern@c2p-inc.com www.c2p-inc.com
are you going to sell that??? if so, please tell me its price
As mentioned in the instructables, the design needs some improvements I think before sold commercially, and unless a company was interested in ordering a large amount of these, it would be hard to justify the extra development expense - this one is more of a proof of concept.

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