Haunted House Bones ~555 timer~

THIS PROJECT WON A DOOR PRIZE FROM THE 555 TIMER CONTEST !
THANKYOU SPARKFUN FOR THE TWENTY BUCKS!
THANKYOU HACKHUT FOR THE FOURTY 555 TIMERS!!
I'M DRUNK ON TIMERS!!!


Welcome 555 Timer enthusiasts!
I came up with this circuit while designing a workshop series at 3rd Ward last fall. I had already run a class called 'Electro-Lab, Robotics Edition' where we learned analog electronics and built a simple robot that is attracted to light and avoids obstacles (Machina Speculatrix). I wanted to try something new and since Halloween was coming up, I figured "Hey, wouldn't it be great if I could come up with a cool 555 Timer circuit for Halloween...". Here it is.
Haunted House Bones is a spooky, multi-media Halloween party kit. Build this circuit to get the basics, and by then you'll be so damn good at working with 555s you'll have 30 more ideas for tricky treats. I'll explain what's going on and how it works after the video.

Step 1 Spooky Sounds ~555 timer~

I wanted to make that classic B-movie ghost sound, a kind of  warbling low "Oooooohhh" often heard on the Scooby-Doo. There are three oscillations that make up the sound. First there is the Wailing Zombie tone itself, then there's the Chilling Vibrato, and then the Creepy Warble. Making an evil tone is easy with the 555 in A-Stable, as most of you already know, but I had to somehow add two more overtones on top of the Wailing Zombie... I dug around '555 sirens' circuits online and tuned one to get the Creepy Warble part of the circuit. It's based on tweaking numerous examples. Since the Creepy Warble sound came from driving the Control Voltage (pin 11) of my Wailing Zombie oscillator, I played around with those for a while, to no avail. After scratching the old noggin, I built the Chilling Vibrato oscillator, and simply tied various parts of it to various parts of the Wailing Zombie  tone generator. Trial and error lead me to discover the great effect of connecting the two Trigger/Threshold's together with a large resistor (smaller that 100K won't work as well. Go ahead, try it). I haven't probed it with a scope (yet), so I don't know what the hell is happening, but hot damn! It Works!
I have a 10K trim-pot to adjust the tone of the Wailing Zombie tone generator. You can dial in a tone that sounds like a Spooky Ghost or a Screaming Banshee or any freaking creepy thing in-between. I know you're a smarty-pants and you are thinking, "Hey, I bet if I replace the Wailing Zombie trim-pot with some other 555 output, It could get even MORE creepy!". That, my friends, is the true path to drooling insomnia.

*** An important note. In my diagrams, the connections have black dots. If there is no black dot, there is no connection. Just keep banging away at it, it will start to oscillate soon :)

Comments

[rtty21]

I LOVE the circuit you have built! I LOVE the video! But I hate the fact that there is no schematic! you need one for your instructable to take off! I highly recommend adding one!
Do you have schematic software?

[Futurologist]

Hi rtty21! I don't understand what you mean?! There are schematics on every page, except the last one, and I have commented the schematics pretty thoroughly. Can you not see them on your browser?

[rtty21]

HAHAHA I didn't notice them! lol! I'm sorry! I will get to work on this project right away! it looks pretty awesome!
AWESOME INSTRUCTABLE!

p.s. try this free schematic program! I use it all the time and its awesome!!!
http://www.cadsoft.de/download.htm

[Futurologist]

Yeah, I've used EAGLE, but they limit the PCB size on their free version. Now I use Design Spark. It's open source, and has a large PCB area. Also, it doesn't have all the bells and whistles that EAGLE has. But I never put bells and whistles in my circuits!