This is for an extreme high intensity LED strobe intrusion deterrent. Extreme strobe disorients burglars even when they have flashlights.Calculator broke and cannot seem to access online RC sites.555 will feed an opto couplerAstable150 ms pulse250 ms interval12 volt motion detector activated (feed to 555 timer)need capacitor and resistor sizes.Celso is headed north and fetching all the ingredients for all my ongoing projects.Strobe is to thwart night time petty thief outdoor kitchen area.

100k, 200k, 1uf cap yields 221 ms / 152 ms according to http://web.udl.es/usuaris/p7806757/555-calculadora/555%20Calculator.htmnever messed much with 555, I just program 6/8 pin micro to blink however I need :)edit!I think I misread your post.133k, 100k, 1uf yields 161ms HIGH, 70ms LOW, 231ms TOTAL

If I can find my TTL Cookbook, it has an RC graph. I built many many projects with these in their time and they were lots of fun. If you are firing a real strobe, be aware that the discharge will play havoc with any receiver in the area.

It's 100 watts of LED's and I think I made a boo-boo within my question...I am seeking a time constant that yields a "shimmering" effect with the pulses. Probably a considerably higher frequency. Similar to that in LED flashlights in warning strobe mode.12 volt motion detector fires a 555 which powers an opto coupler then MOSFET which powers a 25 amp solid state 12 volt relay WHEW...Or I could lose another Cuisinart cooking vessel OUCH

change C1 from 1u to 0.1u, will make the freq 10x higher, or 0.01u for 100x higher

Mex,Perhaps you could just put a 1 meg linear pot in there and adjust till you get the effect you are after?Steve

555 Timer RC Calculations For Strobe | Good Sam Community

12 Replies

Donnoh
Explorer
Jul 30, 2014
Buy an Arduino UNO and program it to do whatever you want. They're cheap and work really well. If you're going to use a 555 timer and build a circuit, you might as well do it the easy way.
MEXICOWANDERER
Explorer
Jul 30, 2014
Yeah I was wondering about that...was hoping the fast switching would be compatible and they wouldn't throw food. Now if those Chinese 25 ampere solid state 3-100 volt relays work out (Gotta get heatstinks)

The strobe has been modified, 160 watts worth of 10 watt 12 volt chips. Only they aren't 12 volt. Try 10. I need to tweak resistance up to reach the optimum watts/calorie peak. Dang I wish I had that power supply here with me. Got a fast way to buck strobing 12 volts down to 10 without generating a lot of heat? DO5 rectifiers are a little scarce down here and I would need 3 of them.
SCVJeff
Explorer
Jul 30, 2014
Hiking Hunter wrote:
Mex,
Why use an opto isolator? Why not just trigger the solid state relay directly (or maybe hit a one stage driver) (I think the 555 will only source 20 mA or so)- and eliminate the isolator and MOSFET?
Actually 200ma. I used to use these for repeater carrier delay timers and drove the relay direct.

It's a pretty tough device
MEXICOWANDERER
Explorer
Jul 30, 2014
Wouldn't it be great to find a burglar wiggling on the floor? This system is meant to disable - like the 116 db piezo siren that also goes off. I don't want thieves to merely get chased away, I want them to feel lots and lots of -pain- in the process.
NinerBikes
Explorer
Jul 30, 2014
Dunno about 100w of LCD's, but on flashlights that are LED, they use PWM's to dim them, and I would assume, if you can slow it down enough, give you a strobe effect?

You do know that strobe effect on lights can also trigger epileptic attacks?
Hiking_Hunter
Explorer
Jul 30, 2014
Mex,
Why use an opto isolator? Why not just trigger the solid state relay directly (or maybe hit a one stage driver) (I think the 555 will only source 20 mA or so)- and eliminate the isolator and MOSFET?
SCVJeff
Explorer
Jul 30, 2014
SteveAE wrote:
Mex,

Perhaps you could just put a 1 meg linear pot in there and adjust till you get the effect you are after?

Steve
that's what I'd do, but probably only 100k 10T with ~10k in series
SteveAE
Explorer
Jul 29, 2014
Mex,

Perhaps you could just put a 1 meg linear pot in there and adjust till you get the effect you are after?

Steve
GordonThree
Explorer
Jul 29, 2014
change C1 from 1u to 0.1u, will make the freq 10x higher, or 0.01u for 100x higher
MEXICOWANDERER
Explorer
Jul 29, 2014
It's 100 watts of LED's and I think I made a boo-boo within my question...

I am seeking a time constant that yields a "shimmering" effect with the pulses. Probably a considerably higher frequency. Similar to that in LED flashlights in warning strobe mode.

12 volt motion detector fires a 555 which powers an opto coupler then MOSFET which powers a 25 amp solid state 12 volt relay WHEW...

Or I could lose another Cuisinart cooking vessel OUCH