To do it you need to use another 555 connected as a bistable. The third 555 will trigger the bistable 555, the bistable output will go high. The output of the bistable will be connected to the reset pin of the last 555 and it will charge C11 (disconnect C11 from the positive power supply and connect it to the output of the bistable). Also, disconnect the THRS pin of the last 555 from the circuit.

 

Well, i wasn't reading the application note the right way and had few errors in schematic too. Last relay is wired from (+) to (555) while others are from (555) to GND. (and have to learn using LT Spice too!).What do you think? So far this is the best i can do.... any advice is welcome! Thanks for all the inputs Mik and Eblc, i am an hobbist and trying to use the little knowledge i have to help running my farm. This circuit is just a better version of my remote starter for the diesel genset. Eblc, you gave me the first schematic for Glows and Crank and it works, this one will control the power output as well. Please let me know if you think i done something wrong.

 

Now, the last 555 will trigger initially, make its output high for a while and then low (voltage on VHRS greater than 2/3 of Vcc). When it is low the relay will turn on. When the output of U3 will go high, U5 will trigger again, its output wil go high for a while and then go low. Try to make the circuit I told you in my last post.

 

Not sure i understand what you mean. Wont the bistable out bi always on and turn off only while relay3 is triggered?

 

Not sure i understand what you mean. Wont the bistable out bi always on and turn off only while relay3 is triggered?

The bistable output will go high when relay 3 will turn on. When this happens, the last 555 in your diagram will start counting time and after some seconds it will turn on the last relay. Take care because you need to increase the delay the last 555 needs to turn on because it start counting when relay 3 will turn on and not when relay 3 will turn off.

 

Yes the lm555 can do that used as monostable for 30 sec, min whatever. Just make the lm555 look like a monstable once triggered nothing will upset the timing except a reset pin 4. need help with that?

 

OK i am having problems using the 555 as bistable, THRS, RT are tied to VCC, OUT is HI and goes low only while relay3 is ON. What am i doing wrong?

 

OK i am having problems using the 555 as bistable, THRS, RT are tied to VCC, OUT is HI and goes low only while relay3 is ON. What am i doing wrong?

Ohhh yes, the bistable is not going to work because it triggers when the power goes on. I missed that, sorry. Use a RS latch, connect the output of the third 555 to its R input and connect the Q' output of the RS to the reset pin of the last 555 and to C1 (remove C1 from the positive supply rail). In reality you may need to buffer the output of the RS with a transistor.

 

Mik, just thought that all this won't really help me. What i am trying to do is to automatically start a genset. Now, all my circuitry would be just fine for starting only but i wont be able to "reverse" the action to turn diesel engine off.
So i am starting from scratch again.
What i need is to be able to press a button (or flick a switch) and start the START sequence and when button is pressed again (or switch toggled back) start the STOP sequence. Does it make sense? What i was doing is not really helping me.
The starting sequence would be as follow:
Ignition on
Glow plugs (10sec)
Crank (4sec)
20sec delay
Power on
==== end of START sequence===
when button is pressed again should do as follow:
Power Off
Stop signal (1 sec)
Ignition OFF
=== end of STOP sequence===
Now if button is pressed again, it will initialize again the STart sequence and so on.
Does it make sense?

 

OK. If relay 1 turns on, does it need to turn off before the second relay turns on? Is it the same (off before next on) with all the relays in sequence except the last one which will stay on until you press the button again?
Also, to turn off the machine, do any relays which were used in the starting process get involved in the switch off of the machine?
I would like a diagram with the relays you need, when do each one needs to be energized, etc, just to make your idea more clear.
Is it important the delays time you said to be exactly the same values or a small deviation is ok?