At the risk of being accused of double posting, after a request on another thread, I'm providing my Pulsinator build docs here since this thread inspired it. Thanks to Rob and everyone else who's contributed to this.
I was in a big rush when I did this project, trying to meet the deadline on Thanksgiving day while doing family stuff. As such, I had to make some last minute changes. When I looked at my files last night, I couldn't find the very last change, so I took the last version I had, compared it to the actual build, and revised the PCB and layout art as shown below. (I hope it's right! If anyone sees any errors, please let me know).
Here are some tips:
1) I replaced D4 with a jumper. I don't recall exactly why, but I think that it helped keep the effect really choppy in rotary switch position #1.
2) To keep the 555 timer from ticking, you need a big cap connected very close to Pin 8. I learned this from Jon Patton (Midwayfair) very near the deadline, so I modified the PCB after it was etched to accommodate the cap. The problem is that there's not much room next to the 555 for a gigantic cap, so I had to mount it off-board. The problem with that is now I had long wires connecting the cap to the board! I might have been able to get by with a 1000μF cap mounted directly next to the chip, but since I didn't have room and had to mount it off board, I had to increase the value to 4700μF.
I've moved C10 to a location on the PCB that should give you more room. See the last two images below. I haven't physically tried the version with the new cap location, so you should probably print out the layout and test your fit on paper before etching.
3) Re the LED/LDR combo, I just butt the LED and LDR together inside a piece of heat shrink tubing. Make sure you don't allow stray light to hit the LDR during testing or after it's boxed up.
4) You can use a CMOS version of the 555, but I tried both versions and found no difference.
5) You might want to breadboard this puppy before commiting to a PCB.
6) If you decide that you like just one of the smoothing filter settings, you could hard-wire it and skip the rotary switch.
7) You could replace the VR2 trimmer with a fixed resistor as all it does is determine the brightness if the rate indicator LED.
8 ) See the schematic for the functions of the other pots.
I welcome comments and suggestions.
