I'm just starting to learn some basic electronics and a friend wanted to get something special for her fiance for Valentine's day. Perfect timing! So, I made up the parts list, waited for them to arrive, and started building. The unit consists of 32 red LEDs, a 555 timer circuit and a binary counter, along with a bunch of supporting components and some creative wiring.
This was my first major electronics project and I certainly learned a great deal from it. Of course, if I already knew everything that I learned, I might not have been quite so eager to begin it... It took me a lot longer than I had expected it to, but I don't regret doing it. If I have any reason to do this on a larger scale, I am seriously thinking about prefabricated circuit boards.
The end result is an array of 32 LEDs that form a heart, piece by piece, and hopefully will make a nice desktop ornament.
Step 1: Parts list
I bought almost everything from Mouser (toggle switch was from Radio Shack), so I have all the part numbers available, if anyone wants, I'll post them in here, but they should be available anywhere. The resistors in the Display section are partly for current limitng and partly for convenience. I may have gone insane if I had to cut and strip that much wire.
Do yourself a favor and don't buy a package of 7 DIP switches and thing you are going to be clever and cut them into pieces and salvage 4 individual switch elements from them... Buy a toggle or latching pushbutton switch and keep away the grey hair and premature baldness.
I was a little annoyed by the cost of the protoboard in relation to the other components, but I was impressed with the quality, so I felt better about trading the cash value of a fast food sandwich for it. :-)
Here's the parts list:
Breadboard (for prototyping)
Soldering Iron (20W-40W)
Standard rosin-core solder
18-20 gauge wire for prototyping and final construction
3M/Nexcare Micropore(tm) Surgical Tape, gentle paper tape, masking tape, gaffer tape, or your favorite unobtrusive adhesive
Massive amounts of free time and patience
1x standard 0.100" pre-drilled protoboard
- Timer/trigger section:
1x 555 timer chip
1x 0.01 uF ceramic capacitor
2x 1K Ohm 1/4 W resistor
1x 470 uF electrolytic capacitor
- Binary counter section:
1x SN74HC590AN or similar binary counter
32x red frosted LEDs, T1 3/4 (5mm) size
8x 2N3904 NPN transistor or similar small-signal transistor
8x 56 Ohm 1/2 W resistor
8x 82 Ohm 1/2 W resistor
1x 4 AAA battery holder
1x 100 uF electrolytic capacitor
1x PCB toggle switch or latching pushbutton