Do you like making things? Do you do it for money, or would like to? If so, you need a business card. These can be your best advertising, but we all know business cards are boring and get thrown away. I have toyed with plastic or etched stainless cards before - these are really cool, but cost a lot, and are not really distinctively "you".
Do you make goods out of leather? Then make a leather business card. Do you make handmade greeting cards? Then make your business card look like one of these! Even better, make one that is actually useful for whoever you're giving it to, so it CAN'T be thrown away. I'm into making electronics, so what better way to advertise my skills than an electronic business card. Here are two experimental "extreme" business cards that are almost impossible for someone to throw away - one in the form of a key ring torch and one card that actually dials me up by itself! This one has a computer inside with more processing power than took the first astronauts to the moon (No, I'm not kidding!), yet the main part costs less than 50 cents. I'm also working on one that plugs into a USB port on a computer so that people can email me directly from a link, or look at a portfolio of my work.
Even if these ideas don't grab you, maybe they'll fire your imagination to think how you could make a truly unique card that uses your skills and tells people how creative you are.
Step 1: The Torch
Firstly the torch. This is the easier of the two. Although you could use some PVC cards to enclose a hand-wired version (keep reading on to see this technique used in the "dialler"), making copies is much easier with a proper PCB. A tutorial on how to make a PCB is beyond the scope of this article, but if you haven't tried it before, it is a really good technique to be able to do and opens up a countless variety of electronic projects. Here is an instructable on a simple toner transfer PCB - personally I find more repeatable and professional results with the photographic method - couldn't find an instructable for this one, but there is plenty of info on the web - I use a very cheap 500W halogen light from the local hardware store to expose mine for a few minutes, and then develop, etch and tin. If there is enough demand, I might get some universal "torch" and "dialler" boards commercially made.
Anyway, assuming you can get a PCB made up, the file which I used is included below - this can be modified on a standard graphics package. If you can't read EPS files, then try the 300dpi bitmapped version included below as well. You can of course use a specialised PCB package, but I wanted an unusual cursive font on mine, so just hand-drew the design on a graphics package. This allowed me to incorporate my name into the actual circuit board - the electric current actually goes though my name! If you want to produce a reasonable batch, you will probably want to tile your image over the page after you have made your changes.
Step 2: The Torch Parts
If you want more information on how both of these projects work technically, including how to properly choose resistor values, see the extra technical information sheet that I have posted below as well. I could make up a batch of 100 of these for under $1 each, including PCB -not bad for some extreme marketing, but you could probably even half this price if you were serious about making these in quantity and could do without the battery holder (see the notes in the parts list about welding batteries).
Step 3: Soldering Time
Step 4: Does it Work?
Do you think that you can handle an even more advanced design? If so, read on to see how the "autodialing card" works ...
Step 5: The Autodialling Business Card!
This is all possible because of miniature programmable microcontrollers - they are now so small and so cheap, they can be put into disposable items. The one I use is made by "Microchip", and costs 39 cents in quantity (and not much more in singles). It can run any small program that you write, and can run it at 4 million instructions per second. I can safely claim (for the moment), that I have the world's most sophisticated business card! You could easily program the microcontroller to do any number of things that fit within the program memory instead - perhaps a simple version of the "business card torch" described earlier that has a flashing light or even "S.O.S." function. Your imagination is the limit here.
A bit of a warning first, though - this is well and truly in the class of an experimental device - it needs considerable tweaking to get working on an individual phone system, and doesn't work on mobiles. It may also not work on some PABX (business phone) systems, depending on the brand. I have quite a bit of experience in electronics, and some good test equipment at my disposal, and this design isn't really setup to be able to use reliably on all phones, so only "extreme experimenters" and those willing to improve the technical aspects of this design should attempt construction - this is definitely not a beginners project, but as mentioned, it might inspire some other designs, rather than being ultimately a really useful one by itself.
Step 6: Parts for the Dialler
If you click on the second picture, you can see some miscellaneous equipment that you will need - some printable OHP transparencies, some spray glue, some PVC solvent cement (used for joining PVC pipes), a device for programming the chip, and on the far left, 5 pins cut off a strip of 0.1" pin headers, to connect the programmer to the board. The PIC programmer itself is ridiculously cheap for what it is ($35.00), and can be used for countless other projects as well - Many thanks to Microchip for making such a great development tool available at such a cheap price. The bottle next to the PVC cement is just to make application of the glue easier - if you do use your own bottle, make sure it isn't made out of a plastic that is dissolved by the cement!
Step 7: Electronic Construction
Step 8: Programming the Card
Go to the "Project" menu again, and select "Build All" - check there are no errors, and you are then ready to program. I use a simple technique of inserting a broken-off strip of 5 pins from a strip of 0.1" header pins into the programmer, and then just touching the 5 pins (see the picture) whilst programming. This is a little fiddly, but as the erase or program cycle only takes a second or so, it is quite manageable. If you are experimenting, it is well worth soldering the strip of 5 pins onto the board until you have finished your changes. When you are ready to program, select the "Erase" and then "Program" options from the "Programmer" menu. If all works OK, you should be able to remove the programmer, and tap the piezo to hear your phone number being dialled!
Step 9: Creating the Graphic
Note that I made a conscious decision to omit my phone number from the card to force someone to try it out. It may be a wiser decision to list the number on the card as well in case of problems getting it to work!
Step 10: Sticking it on
Step 11: Encapsulating it
Place the circuit board on the card, and draw around with an OHP marker or similar. Then cut out the inside with a pair of small, sharp scissors. Doesn't really matter if you make a cut in from the side, as this will be hidden anyway, but if you are a little retentive like me, you can drill a hole in the middle first, and then cut out the inside without making a cut to the edge. The dotted line shows where you need to cut slightly inside the line to form a lip where you can glue the piezo disk.
Step 12: Encapsulating it Vol II
Step 13: Encapsulating it Vol III
The overall card thickness is governed by the batteries (1/16" or 1.6mm) - I have added another two PVC cards to the front and back, but you could make these even thinner so that the whole card is approaching this thickness of just the batteries.
Step 14: All Done!
Click here to see a video of the card in action - I'm afraid it isn't the world's most exciting video, but at least it will show you the card in operation. The dialling tones are very quiet, so you might need to turn your volume up to be able to hear it.
I did warn you that this took a little skill to make, and that it was very experimental - I get around a 50% success rate maximum at the moment when dialling on my home phone only by considerable tweaking of the mounting arrangements, and getting the number recognised accurately is highly dependent on a number of factors including your exchange and the mounting of the piezo disk, including the shape of the cavity cut inside the card. I may work on some improvements to this design, as it could get recognition close to 100% (have managed to do this now using the computer to drive the card as a simulator - for those who are very technically minded, I could redesign the card to drive the piezo with a pseudo sine wave rather than a square wave using filtered PWM signals, and increase the tone and space times as well.), although I probably won't bother doing this unless anyone was interested in getting these sort of cards produced in bulk, (which I doubt!). If you are still interested in how the design works, and are a bit of a techno-nerd like me, then check out the technical notes below to look at how this whole thing works.
In case you were wondering, this doesn't work from a mobile phone, as you need a dial tone from the exchange for it to recognise the DTMF tones generated, but as I mentioned, this is more of a novelty marketing exercise than a universal way to dial a number- certainly, it shouldn't be attempted unless you are really up for the challenge of improving the design. It is hopefully also a neat tutorial into some other useful techniques like designing enclosures for miniature electronic devices using ID cards and getting nice graphic overlays done. Finally, hopefully it will also inspire some ideas for other electronic business cards - certainly some of the ideas that people have emailed me privately since posting this have been fantastic, so I know this at least is happening! Time for you to now start designing your own version of the world's most technically advanced business card!