Instructables

on/off timer for Halloween prop?

Hi All:
Last year I built a "glow wall" for a Halloween prop using a fluorescent black light from Wal-Mart as the light source.
See the following link for the glow wall description:
    http://glowinc.com/glow-in-the-dark/shadow-wall.aspx
This worked great! The only bad thing was sitting by the switch all night to turn the lamp on/off for the kids.
This year I'd like to add timer that would turn the light on for ~30 seconds and then off for ~30 seconds.
Any ideas/suggestions?
Thanks for the help!
amb
 

frollard3 years ago
According to the website linked, you want the exposure light on for about 5 seconds, then off for 30.

This isn't terribly hard, but can be accomplished a few ways:

I would personally use a decade counter and 555 timer to make a 5 second 'strike a pose' then 5 second 'hold still/expose'. Having the 0-8 counts trigger the 555 to keep going, but the 9th would latch the 555 to be monostable and disable the decade...

OR, you could just use a microcontroller -- something like an arduino would fit the bill perfectly, incorporating sensors, outputs, possibly even a camera trigger to catch the action!
amb (author) 3 years ago
Thanks to all for your great ideas!
amb
jeff-o3 years ago
Grab an electronic lighting timer. They're typically used to control accent lighting outside, but would work just as well for this. It's got to be electronic though, because the mechanical ones won't be able to switch on and off that frequently.
Re-design3 years ago
You need to build a "555 astable" circuit like the one described here. (go to the section heading "astable"). You vary the resistances and the capacitances to get the time on/off you want. It is basically a square wave generator that will generate on/off pulses that you need.
Then where it lists "load" put a relay there that will work on the supply voltage but control your 120 volt lights.