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I will explain existing hardware followed by my desired operation thereof.

I have a security door the controller of which has failed. The door has four electronic deadbolts. -- A) Two open when un-powered; close when powered AND door is closed (as determined by magnetic reed switch internal to these two deadbolts) -- B) Two open when unpowered and close when powered (with no internal sensors of door state)

There is a tactile switch with both NC and NO connectors inside to detect proper closure of the door which can be used.

My problem relates to the manual escape button found on the inside of the door. When pressed momentarily this should: -- Un-Power the A deadbolts for 5 seconds; then power them again. -- Power B deadbolts for 5 seconds and close ONLY IF tactile switches reveal that door is closed (otherwise the door would not be able to close against closed bolts)

I have this partially fixed by using one LM555 as a monostable timer unpowering A bolts for 5s and another LM555 as a bistable set to latch to powered state on button press. Both LM555's triggered simultaneously.

Problem is that after closing the door the B deadbolts do not re-latch without manual reset of the 2nd LM555.

My hope is that someone can advise as to how to develop an elegant solution to this problem which will allow: --> Opening door for 5s on single button press --> Automatic re-locking after 5s if door is again closed --> Keeping door unlocked if not closed after 5s --> Locking door again after door is closed (both before and after 5s has elapsed following button press).

I am sure this will be easy for someone experienced in the use of these timers.

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    \$\begingroup\$ So what have you tried so far or are you expecting a fully proven design to be presented to you? How much of the value of the goods contained behind the security door are you prepared to pay a consultant because, it seems to me this might be your best option. \$\endgroup\$ – Andy aka Jan 10 '18 at 14:12
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    \$\begingroup\$ My recommendation is to pitch the 555s into the garbage and fix this with something like an Arduino Nano. With the software you put toward this you can easily solve all the state save/change issues and correct other edge behaviors that you discover along the way to perfecting the replacement controller without having to add hardware to it again and again. \$\endgroup\$ – Michael Karas Jan 10 '18 at 15:00
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    \$\begingroup\$ The trouble with finding someone experienced with the use of 555 timers is that the better engineers quickly realize the 555's limitations and don't become experienced (because they move-on to better things) whilst the ones that plod along using the 555 for ever and a day are probably not really suited to design anything with much complexity. \$\endgroup\$ – Andy aka Jan 10 '18 at 15:52
  • \$\begingroup\$ Do you intend two distinct concepts? One that includes the use of a magnetic reed relay for sensing door position and a second one that does NOT include this feature? The highlighted section reads like that to me, but perhaps I'm mistaken. (My logic is that your two cases appear identical in function, the only distinction being whether or not a door is detected... but they both say the same thing, regardless. So that's my confusion.) \$\endgroup\$ – jonk Jan 10 '18 at 17:00
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Assuming I am not miss-understanding your requirements, you ought to be able to do this simply with one 555 and a couple of MOSFETS.

schematic

simulate this circuit – Schematic created using CircuitLab

How that ties into the rest of your circuit is anyone's guess though. If the door open switch is already being handled elsewhere then either bring the signal over to a parallel MOSFET as shown below, or diode OR into the gate of M1 with an added pull-down.

schematic

simulate this circuit

schematic

simulate this circuit

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