Hi.
I need to send one impulse that should simulate button press of some device. I can use 12V power supply for this electronics.
The idea was to use 12 relay and NE555 to make this work. So this should work something like this:
-- plug the 12 power supply
-- wait 5 minutes
-- trigger relay for one second
-- repeat all the time
Suggestions for schematics ?
GM
Years ago John Fields posted a schematic for a one-second-per-hour pulse generator, based on a 1Hz clock into a CD4040 divider with some gates and a type-D flip flop, see AoE III, page 467.
With those parts and different gate arrangements, you can create many types of 1-second pulsing. You'll be selecting for 5*60-1 = 299 clocks.
--
Thanks,
- Win
An 0.8-Hz pulser going into a divide-by-256 counter with a terminal count (carry) output will get there with no state decoding required. Something like a CD40103 ought to work OK, assuming that a 1.2 s pulse is okay.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
5 minutes is on the edge of the usble range of the 555. also 555 start-up has the first period about 20% longer than subsequent periods,
I'd be looking at the CD4060 instead. wire the divide by 256 output to reset and to the transistor that drives the relay. put a capacitor parallel with the relay the relay pulses will be about 1.2 seconds long with the R-C adjusted for 300/256s, (or seped the RC up to 300/512 and use the divide by 512 to get 0.6s pulses, you could possibly add a capacitor parallel with the relay to stretch that a bit..
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Why build hardware when you can buy off the shelf easily? Arduino and other MCUs are available with any manner of I/O which will drive a relay. Programming is all but idiot simple. I recommend using Forth. You can learn to program in it in an hour and be very effective.
comp.lang.forth
Never be constrained by the limitations of analog again.
-- Rick C
Buy it from Ebay for ~$5.00. For example:
"DC 12v 24v LED Display Cycle Delay Timing Timer Relay Switch Turn ON/OFF Module"
Search "delay timer" in Ebay for other versions, but I think the one above can do exactly what you want.
Ed
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