Latching dual momentary switchs with a single 555 Timer. Latching +Signal with Delay +Signal

Thread Starter

Walter2k

Joined Mar 1, 2021
9
I have a bread board which I am able to latch a timer circuit (B) with either of two switches.
The overall circuit needs to either apply a signal on circuit (A) or not, prior to applying a signal on circuit (B)
If switch (B) is pushed and held then the timer charges and latches the circuit without circuit (A) being charged.
If switch (A) is pushed and held then the circuit (A) is immediately charged and starts charging circuit (B) until (B) is latched.
Problem is when switch(A) is released circuit(A) is not latched as shown in included PDF schematic.
Or not shown, able to get circuit(A) to latch but it happens immediately and not desired.
The desired goal is to immediately charge circuit(A) and AFTER circuit(B) is latched, also latch circuit(A)

I tried various iterations and am just stuck.
 

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Thread Starter

Walter2k

Joined Mar 1, 2021
9
I have a bread board which I am able to latch a timer circuit (B) with either of two switches.
The overall circuit needs to either apply a signal on circuit (A) or not, prior to applying a signal on circuit (B)
If switch (B) is pushed and held then the timer charges and latches the circuit without circuit (A) being charged.
If switch (A) is pushed and held then the circuit (A) is immediately charged and starts charging circuit (B) until (B) is latched.
Problem is when switch(A) is released circuit(A) is not latched as shown in included PDF schematic.
Or not shown, able to get circuit(A) to latch but it happens immediately and not desired.
The desired goal is to immediately charge circuit(A) and AFTER circuit(B) is latched, also latch circuit(A)

I tried various iterations and am just stuck.
Oh, and I have an interupt relay that will lockout the switch(A) from being changed while circuit(B) is engaged. Just showed the simplest form of the circuit.
 

AnalogKid

Joined Aug 1, 2013
9,354
1. Your relay symbol shows NO and NC terminals, but no Common terminals.

2. The 555 Reset input ***must*** be connected to Vcc if unused.

3. There are no switches on the schematic.

4. You seem to be using the word "charge" for two different things. Please clarify your question. Maybe, add a table showing the various input action combinations and the resulting outputs.

5. Please add a reference designator to each component on the schematic.

ak
 

Thread Starter

Walter2k

Joined Mar 1, 2021
9
1. Your relay symbol shows NO and NC terminals, but no Common terminals.

2. The 555 Reset input ***must*** be connected to Vcc if unused.

3. There are no switches on the schematic.

4. You seem to be using the word "charge" for two different things. Please clarify your question. Maybe, add a table showing the various input action combinations and the resulting outputs.

5. Please add a reference designator to each component on the schematic.

ak
Yes, please clarify exactly what you are trying to do.
Clarified a bit. The bottom left shows the PROBLEM with how it stands using the current schematic and the DESIRED outcome below it.
 

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Thread Starter

Walter2k

Joined Mar 1, 2021
9
On the relays the common is the one on the left unlabled. I am seeing all sorts of nomeclature for the relays. I have yet to find a standarized labeling for relays. I should have put COM on there but forgot before I uploaded the new pdf.
 
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eetech00

Joined Jun 8, 2013
2,576
Does this do what you want?
Press PB, K1 energizes immediately and starts the timing circuit.
If PB held for 3 seconds, K2 energizes the load.
PBR is optional reset button, otherwise connect "PBR" wire to +12v

1614620917835.png
 

Thread Starter

Walter2k

Joined Mar 1, 2021
9
Does this do what you want?
...
It looks like it covers that specific problem, but I am not electrically educated enough to figure it out in my head, Since I don't have the M1(MOSFET) on hand, I have been trying to put this in to LTSpice. I have a headache now after beating my head into the keyboard to get a ANY mechanical switch to work. My version is from 2010 so has been a while since I worked with it.
Trying to verifiy that it meets the functions of the 3 that are working. Thank you for you effort so far, it points out a few things I should be keeping an eye on, like the reverse flow of electrons. I will let you know how it turns out one way or the other.
 

Thread Starter

Walter2k

Joined Mar 1, 2021
9
Well, I ended up changing it around to get the delays and locking out. Kind of spikey on the RLYRUN on the far right.
PB-FWD to RLY-Run
PB-Rev to RLY-Out
PB-Stop releases all Relays
Once RLY-Run then RLY-LCK to freeze state
Once running lockout all PBs except PB-STOP.
Instead of sending a HI/LO first,
send a combined HI/RUN or LO/RUN.
Still have a 3 second delay to avoid
accidental start ups and allows for motor
to stop prior to starting up again.
One thing I learned for sure is I don't like the new version of LTspice. I can save a file as a new one and open it and it may or may not give the same results from previous. argh I am already confused enough with my own inability.
If anyone has a pointer on how to get rid of those spikes I would greatly appreciate it. Regardless, thank you to those that helped.
 

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Last edited:

eetech00

Joined Jun 8, 2013
2,576
Well, I ended up changing it around to get the delays and locking out. Kind of spikey on the RLYRUN on the far right.
PB-FWD to RLY-Run
PB-Rev to RLY-Out
PB-Stop releases all Relays
Once RLY-Run then RLY-LCK to freeze state
Once running lockout all PBs except PB-STOP.
Instead of sending a HI/LO first,
send a combined HI/RUN or LO/RUN.
Still have a 3 second delay to avoid
accidental start ups and allows for motor
to stop prior to starting up again.
One thing I learned for sure is I don't like the new version of LTspice. I can save a file as a new one and open it and it may or may not give the same results from previous. argh I am already confused enough with my own inability.
If anyone has a pointer on how to get rid of those spikes I would greatly appreciate it. Regardless, thank you to those that helped.
Hi

Instead of explaining your circuit operation, please explain what you are trying to control and how it should be controlled.

Such as "I'd like the circuit to control a motor. Button A should start the motor if held down for 3 seconds. Button B should stop the motor.", etc.

You might get more help.
 

Thread Starter

Walter2k

Joined Mar 1, 2021
9
Hi

Instead of explaining your circuit operation, please explain what you are trying to control and how it should be controlled.

Such as "I'd like the circuit to control a motor. Button A should start the motor if held down for 3 seconds. Button B should stop the motor.", etc.

You might get more help.
Already finished it. This is just to permit a 24v signal with a delay. I could have used an Arduino but wanted to learn more about transitors. I scrapped that idea and went to relays and changed the way I would use it. Could have done that from the start, but was hoping there was a means to using the existing 555's reset to accomplish the previous task. I don't think that is possible or someone may have suggested it already. Had a suggestion of how to achieve what I had already accomplished though without using the 555.
 

eetech00

Joined Jun 8, 2013
2,576
Already finished it. This is just to permit a 24v signal with a delay. I could have used an Arduino but wanted to learn more about transitors. I scrapped that idea and went to relays and changed the way I would use it. Could have done that from the start, but was hoping there was a means to using the existing 555's reset to accomplish the previous task. I don't think that is possible or someone may have suggested it already. Had a suggestion of how to achieve what I had already accomplished though without using the 555.
Glad you solved your problem.

For future reference, it would be good if your posted your solution, so others can benefit.
That's the purpose of the forum.
 

Thread Starter

Walter2k

Joined Mar 1, 2021
9
Glad you solved your problem.

For future reference, it would be good if your posted your solution, so others can benefit.
That's the purpose of the forum.
I agree and that is why I did, all you need to do is look at what you replied to. The only thing at that point was the spikes on the coils I am guessing.

Yes, it seems that often the TS is looking for a solution to his solution rather than a solution to his problem.
Your correct about "often" but at the same time people might be stuck on a certain aspect of a project in the course of learning. I have "often" seen people getting taken down a different road than what they were currently on. Some times I think resources on hand may be the limiting factor. Such as in my case, I have a BUNCH of 555's and optocouplers. Unfortunately the optos I have in combination with the PNP & NPN and momentary switches were not going to play well with me.
 
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Thread Starter

Walter2k

Joined Mar 1, 2021
9
OH and BTW what I learned was to NEVER treat a transistor to a mechnical switch as there is a big difference to 0V and NO Volts ie disconnected. There is probably a way to handle it that you guys might know of, but I will just stay away from that combination.
 
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