Anyway to auto reset auto off switch using NE555 IC

Thread Starter

aruneshdutta

Joined Feb 21, 2017
11
I have a need to turn off a load after set duration like 3min(have used different value of Capacitor and resistor) I am using a NE555 IC and going ahead with designing as shown below, my application in breadboard is working but I'll to press switch each time the off timer is needed to activated, is there any way I can implement a mechanism to repeat without pressing reset button like after 3min it should again operate and repeat entire process as I'll need it in place where user won't be there for pressing button after each cycle..do guide if any other option ..thx
May be an image of floor plan and text that says 'B 9V R1 100k U1 R3 10k R 3 7 DC 5 cv TR R2 220 6 CHD ΤΗ NE555 Monostable C2 0.01uF C1 10uF CírcuitDigest'
 
Last edited:

crutschow

Joined Mar 14, 2008
28,474
Use a second 555 monostable to trigger the first, and use the first to trigger the second.
To do that you connect the output of one to the TR input of the other through a capacitor.
 

Ian0

Joined Aug 7, 2020
4,054
Do I understand that you want 3 minutes on, 3 minutes off, and repeat indefinitely?
I’d suggest a CD4060.
You can use the RESET input to restart it manually.
 

Thread Starter

aruneshdutta

Joined Feb 21, 2017
11
no, I want it to automatically start but again reset/restart after duration instead of staying ideal after the particular minutes, actually it would be connected to a buzzer monitoring water which I want to sound for 3 min but stop after it later again if water reaches a level the buzzer should sound this should happen without like current user input of reset button which is not possible
 

Thread Starter

aruneshdutta

Joined Feb 21, 2017
11
Hello

I'll explain u.. a buzzer that'll sound for 3 min after water level in tank reaches certain level that output to buzzer is controlled by NE555 timer as it will go on making alarm without it, now using NE555 timer with above circuit for 3 min it will definitely stop the buzzer after 3 min what my need is but then it will not start again until the reset button as shown in the circuit is pressed to trigger which is not possible in my case as I want it to make alarm >reset/restart automatically> again if water reaches a level make alarm..hope I'm clear
 

Thread Starter

aruneshdutta

Joined Feb 21, 2017
11
As an alternate, If the two times can be the same, you could use one 555 astable driving a toggle flip-flop.
thx had a query I think in astable(do correct me if wrong) it will periodically do things , but my need is I am interested to connect a load which is a buzzer which will make sound after water reaches a level it needs to turn off say 3min(based on size of capacitor I use) but should return to normal without pressing reset button and again sound if any water level is reached say after 1 hr etc
 

Ian0

Joined Aug 7, 2020
4,054
If I can get this clear:
Water level reaches sensor - alarm sounds
3 minutes later - alarm stops

for the alarm to restart, must the water level fall below the sensor, then rise up to the sensor again?

If not, when should the alarm restart?
 

Thread Starter

aruneshdutta

Joined Feb 21, 2017
11
If I can get this clear:
Water level reaches sensor - alarm sounds
3 minutes later - alarm stops

for the alarm to restart, must the water level fall below the sensor, then rise up to the sensor again?

If not, when should the alarm restart?

leave the sensor part as sensor isn't used rather electrical charge, main discussion is when water fills to certain level sound will beep till 3 min but how can it again receive the sound alert say after 1 hr when tank fills as in this situation we need to press reset button to start again
 

zophas

Joined Jul 16, 2021
157
I think what the TS means is: Water reaches a certain level then sound alarm. No one comes to sort things out then sound alarm again in say 1 hour. Repeat sounding alarm until someone presses reset button. (Who I assume also do something about the water.)
 
Top