musical greeting cards - make something useful from this electronic novelty

Electronic greeting cards (that play a 3 melody when opened) are becoming not only more popular but also more varied. Now there are a number of variations on the original "Happy Birthday" theme. Hid- den inside the card is a miniature printed circuit board (shown in photo 1) connec- ted to a piezo buzzer. A single chip does all the work. We added a few embellish- ments to this IC and finished up with the circuit shown in figure 1. One of the possibilities The circuit diagram illustrates just one of the many possible circuits that could be made using the greeting card chip. To prepare the chip for use first take it out of the card. It will probably look similar to the one shown in the photograph. Remove musical greeting cards elektor december 1984 musical greeting cards the battery, disconnect the piezo buzzer and then bend the switch so that it is per- manently closed. Wires can now be soldered onto the points marked 1, 2 and 3. The circuit shown in figure 1 was de- signed as a mu...