Nuts and Volts - October 2010

■ FIGURE 5. The inside of the frame.

are available on the Nuts & Volts website (click “Magazine” and then “Downloads” and find “Shazam”). You will need to download the free software from www.expresspcb.com to view the schematic and the PCB (printed circuit board). (However, I think you will find it cheaper to order the boards from the Nuts & Volts store.)

Also available is a pre-programmed PIC16F690 if you don’t want to program it yourself.

If you don’t have a PIC 2 programmer and still want to program, put a 20-pin socket in IC1 and solder. Note that the square pin is pin 1 on both ICs. Solder IC2, the resistors, and capacitors into their proper areas. I put an extra pad in for C1 so that you can use either 2. 5 mm or 3 mm radial capacitors. Note the “+-” on the 220 µF and 4. 7 µF caps. Solder in the three male headers at SPK, the mic, S2, the five male headers in the programming

■ FIGURE 7. The back of the frame.

pads, and the three-position female headers in the PIR area. If using a three D, three C, or three AA battery pack, thread the wire through the strain relief hole and solder the red lead to the + and the black to the -. (All chips will run on 4. 5 volts.) You can also use a five volt battery eliminator. Do not use four batteries as the PIR will lock up!

If programming with a PIC 2, make sure you place the DIP switches in the open position. The chip can also be programmed by other programmers if it’s removed from the board. The assembly files are also on the N&V website.

■ FIGURE 6. Inside the frame showing the flash.

Display

The display I built is rather unique. I made a transparency of the picture drawn by Charles Allan Gilbert called “All is Vanity.” It is a picture of a woman sitting in front of her mirror and vanity. However, when viewed farther back, it becomes a skull. The picture is available on the N&V website if you want to use it.

The frame I used was the cheapest 8” x 11” stand-up frame I could find. The back was removed. I tacked the transparency on each corner to the glass using super glue. A sheet of white tissue paper was tacked to the transparency on each corner giving a semi transparent background but still showing off the picture. I took the back and added a 3/8” x 1” pine strip to make it look like a shadow box mount and painted the outside with a flat black paint. The inside was left unpainted. Holes were drilled in a zig-zag pattern with a #60 drill for the LEDs. The Superbrite LEDs were pushed through the back and held with wire wrap. The circuit board was mounted on the inside of the box in the left lower corner using 1/4” standoffs and 6-32 screws. However, I found that the PIR would not detect through either the transparency or the glass. I ended up drilling a 7/8” hole through the bottom of the picture frame and inserted the PIR into this hole from the inside, then tacked it with hot glue. I used a 3-pin male header and plugged it into the PIR female header, then wire-wrapped the PIR using the wire as an extension.