Futurologist

I learned everything I know about 555 timers from Forrest Mims III. His book, 'Timer, Op Amp & Optoelectronics Circuits & Projects' is where I got the building blocks for this project.If you are in need of a constant sounds, then you should not use the one-shot circuit. I'm using the oscillating parts of the timers to effect the oscillator output. at the end, not the outputs of the actual timers.

Design Spark is not open source. It's free, as in free beer.Now I use KiCad. it IS open source.

Hi remedios667,You can definitely build the circuit with 555's instead of 556's. you would need 4 555 chips to make the Haunted House Bones sounds.I can't put together a schematic for you, but you can easily correlate from the 556 to 555. Please share your results when you make it!