|I had these 2 very basic PCB's laying around for years (see picture) and when I was experimenting with some oscillators I finally had a good use for them.
I put 2 40106 chips on the first PCB creating a total of 12 oscillators. 6 oscillators have a low frequency and are connected to the other 6 which have a high (audio range) frequency. All the oscillators have a LDR for speed control. My first thought was to put 12 oscillators on the other PCB driving 12 LED's so they could control the speed of the 12 oscillators on the first PCB, but I wanted something different,.. So I used a binary to BCD decoder chip to drive the LEDs and just for fun I connected a 7 segment LED display to it as well. I also put in 1 auto-fading RGB LED which makes it produce great siren like sounds, it can be selected with the Pulsar switch. The Warp switch puts a 10K resistor in series with the Vcc pin(s) of the 40106 chip(s). (I'm not sure if it's connected to both)
I had some different thoughts about how to construct everything making it possible for the LEDs to shine on the LDRs. One of them was to make some sort of frame with PCB1 on the bottom and PCB2 upside down above it. But I finally ended up with putting everything in a (MDF) box with a plexiglas cover and attached some long wires to the LEDs so I can bend them into position. I used silver paint for the inside and glossy white on the outside. I think I came up with the name "Cosmic Space Beeper" because I was listening a lot to FSOL at the time and they used a sample of a voice saying "cosmic space music" so that probably got into my subconsciousness.
The Cosmic Space Beeper can produce horrible sounds and forcing somebody to listen to it could be considered torture. But this changes when you connect it to a delay. Then it turns into a real cosmic space beeper and I wouldn't be surprised if it gets the attention of something out there,..
(besides from beeping it's also a nice box with flashing LEDs)