CD4538 or 74HC4538 are dual monostable multivibrators that will run on 3 V.

Definitely a better choice for monostable circuits. Retriggerable and non-retriggerable configurations, able to trigger from falling or rising edges, dual complemetary outputs, two vibrators in a single package.

But many people like to stick to the 555 and variants.

 

many people like to stick to the 555 and variants.

Rather like all those who still use the 741 or LM324 op amps.

 

ok, so the LEDs are not driving the 7555 excessively, and are under the mentioned ma.
Ok so this is my fault as I never include the usage for the circuit, as several times Ive been made fun of by various members
in the past.
So here is the usage of the circuit. I have a porcelain frog on my front step that ribbits whenever someone comes close to it. It uses a LDR photocell, that I guess is balanced, that becomes unbalanced when the light changes. This is used in a lot of toys for the purpose of sensing someone approaching. Well, lately it just croaks continuously, no mater the light situation, and I have replaced the Batteries (2x 1.5 AA Batteries), cleaned the sensor etc etc, and it still just croaks non stop. So I was hoping to create a circuit that will lock it out after 1 croak, for a period of time, an maybe add a more sophisticated sensor, whos sensitivity can be adjusted.
My partner LOVES this stupid thing, and Ive promised to attempt to fix it.
There ya go, I apologize for not adding this info from the start.

 

So I was hoping to create a circuit that will lock it out after 1 croak, for a period of time, an maybe add a more sophisticated sensor, whos sensitivity can be adjusted.

For starters, if you switch power to the frog for 1 second every 40 seconds won't that accomplish the same?

 

For starters, if you switch power to the frog for 1 second every 40 seconds won't that accomplish the same?

It would , but I would still prefer to use a sensor as well, such as a infared sensor module, such as the one attatched

 

hi Kim,
Those HC SR50X require a 5V minimum Vsupply.
E
I prefer the 501 modules, you have control over the settings.

 

hi Kim,
Those HC SR50X require a 5V minimum Vsupply.
E

I can give it its own 9vdc power supply. I can have 3v just for the sound effect

 

Hi Kim,
What PIR detection cover volume do you require, ie: area of PIR detection?
E

 

Hi Kim,
What PIR detection cover volume do you require, ie: area of PIR detection?
E

not much, maybe 6 feet. A lesser detection area will also hopefully lessen false triggers...I hope

 

hi Kim,
One technique used is to, partially mask off side areas of the Fresnel lens
On the 501 version you can set the Sensitivity and Output On period, also it can be set in two states of triggering.
There is an option on the PCB module to add an LDR for Day/Nite operation
Check the d/s I posted.
Pets and wild animals can be a trigger nuisance !!!

Check this microwave module option, ref this PDF

E

 

hi Kim,
One technique used is to, partially mask off side areas of the Fresnel lens
On the 501 version you can set the Sensitivity and Output On period, also it can be set in two states of triggering.
There is an option on the PCB module to add an LDR for Day/Nite operation
Check the d/s I posted.
Pets and wild animals can be a trigger nuisance !!!

Check this microwave module option, ref this PDF

E

Im not worried about pests triggering

 

Im not worried about pests triggering

The SR505 module has a output ON delay time of appx 6 to 10 seconds meaning the Frog will croak for that amount of time, is that a problem?

 

The SR505 module has a output ON delay time of appx 6 to 10 seconds meaning the Frog will croak for that amount of time, is that a problem?

That sounds good

 

That sounds good

Then option #1 on the module should suffice I would think?

 

hi,
If required, the On time period can be increased by adding a low value capacitor across the existing timing cap.

E

 

If this SR505 module is mounted in a standard hobbyist plastic case, are the walls of the case transparent to the signal, or does it need perforation for the signal to escape, and be received??

 

I suppose you could try it completely enclosed inside the case and see if that works satisfactory. Otherwise
I would cut an exact diameter hole in the case to allow the lens to pass through. The lens has a wider flange at the bottom which would prevent it from falling out.

 

Thank you everyone for your help. Everyone's intellect is amazing!!