sequential transistor relay

Good Day Sir/Ma'am,

I'm a technician and I am in need of schematic diagram of a sequential four transistor driven relay which i will needing for my project as part of my study.
I have a single input source driven by LDR, the first relay should be turned on and then off,while the second, third and fourth relay should be remain off, then when the LDR is active the second relay should be turned on and then off for a few seconds. and so with the third and fourth relay. when one relay is active the other should not be active.

thank you very much.

 

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On Sun, 12 Mar 2017 03:50:27 -0700 (PDT), mcgyver009@gmail.com wrote:

Good Day Sir/Ma'am,

I'm a technician and I am in need of schematic diagram of a sequential four transistor driven relay which i will needing for my project as part of my study.
I have a single input source driven by LDR, the first relay should be turned on and then off,while the second, third and fourth relay should be remain off, then when the LDR is active the second relay should be turned on and then off for a few seconds. and so with the third and fourth relay. when one relay is active the other should not be active.

thank you very much.

Check out Picaxe controllers. Cheap, easy to apply, easier than
dealing with a hard-wired circuit if you want to tweak the timing.
Timing can be easily set with millisecond precision. Outputs can
drive sensitive relays directly but a relay driver like one of the ULM
series of IC would up the drive to a half amp per relay.

Their forum is excellent for people willing to help you get started.

Arduino can also do it, but costs a little more and has a steeper
learning curve. Another good forum if you need help. Arduino is way
over-kill IMO but it should be a lot of fun learning..

A string of 555 monostables could be used to do the same thing, but
not as flexible and each would have be adjusted individually if timing
precision is a design requirement.

How tight are the timing requirements? Is there a need to
abort/truncate the sequence?