Instructables

Step 6: Parts for the Dialler

Here you can see the main parts. As before, a detailed parts list for both projects can be seen below if you are mad enough to actually want to build it. The items on the left are blank PVC ID cards - available very cheaply. These can be used to enclose all sorts of other electronic gadgets (more about that later). The batteries are in the middle - I used two PCB-mount CR2016 batteries, as these are very thin (1/32" or 1.6mm). The PCB is next to these (see below for an EPS file, and a 300dpi bitmapped version if you can't read an EPS), and on the right is a piezo disk which is used to create the tones, and also as a "switch" to detect the tapping. On the bottom is one of the microcontrollers (actually, shown here is a strip that contained five of them) - it is a PIC 10F200.

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!
What about using a reed switch so when you put the card near the magnet in the phone receiver it dials (semi-)automatically?