Please help modified a circuit

[cannibal]

Hi

No the previose circuit gets timeout in dark the circuit works !!

by the way I added the capacior and the resistor like you said and the system is not working at all

I perefer to use the previose circuit

it has less parts

you know I will going to use 8 similer circuits with other circuits

total 16 circuits

 

[audioguru]

My last circuit doesn't work because it gets dark too slowly to make a pulse for the coupling capacitor into pin 2 on the 555. The two-transistors circuit is a Schmitt Trigger and its snap action will make a pulse for it to work.

Many articles about the 555 monostable timer say that it doesn't finish timing if pin 2 is low. That is why I added a coupling capacitor and resistor at pin 2.

 

[cannibal]

ljcox
sorry , you were right it worked without Q3

audioguru
You are the boss


Is this the right way to connect the extra part ?!!!

 

[audioguru]

Now you have two light detector circuits that have an output that is too slow to trigger the 555. They trigger the 555 only if it gets dark very quickly.

You need two Schmitt Trigger darkness detector circuits and an OR gate.

 

[cannibal]

Wow
easy
I didn't understand what youv'e said

if it's possible to apply it as drowing it will be nice and easy to understand by me

 

[audioguru]

The transistor won't work. It gets dark very slowly. Then there isn't a pulse through the coupling capacitor to trigger the 555.

You need two of the Schmitt Trigger darkness detector circuits which have a snap action when the input is slow. The two circuits must be combined with an OR gate that feeds the coupling capacitor.

 

[cannibal]

Well thanks for the information
I will buy today new photoresistor and try to test


by the way

I am thinking to add some features to this circuit
your ideas will be helpful to me

I mean like when it gets dark the circuit will send signal to a receiver
something like that

hope my english is understandble

 

[ljcox]

Here is how I would do it.

This circuit solves the issue about slow changes of light level since the IC is a Schmitt Trigger NAND and will trigger at a particular voltage level.

 

[cannibal]

wow

in the attachment I see 3 IC's
so if I apply this circuit it will cost me more then making another saprate circuit with other photoresistor

 

[audioguru]

The new circuit uses 3 of the 4 gates inside a CD4093 IC. The unused 4th gate has its inputs connected to ground.

 

[cannibal]

can it be please in my circuit daigram so I can know how to connect

because like this I may miss something while making connections

 

[ljcox]

can it be please in my circuit daigram so I can know how to connect

because like this I may miss something while making connections

I don't understand your question.

 

[ericgibbs]

I don't understand your question.

Morning Len,

I think he is asking for ic pin numbers for your logic drawing?

 

[ljcox]

Good evening Eric,
The pin numbers can be found in the data sheet for the IC.

Cannibal, let me know if you can't find a data sheet or need more help.

 

[cannibal]

Hello

Thank you Mr.ljcox and thanks to all you guys
I learned a lot of things from your experience I really appreciate it

I decided to use this circuit because it's working just fine and I tested it in my breadboard and every thing seems to work just fine, like I wanted

I test it in dark and light mode all fine no problems at all
the response and sensitivity perfect

you know I want to make 7 more circuits like this one, that’s why I am looking for less components and less cost

I have one more request I know I am starting to bother you guys but I really need your help

I want to integrate this (7 Segment LED Counter) to my circuit

https://www.aaroncake.net/circuits/counter.asp

I bought the components but you know lack in knowledge and lack in connections skill

I want that when the buzzer is activated it will send pulses to the new (7 Segment LED Counter) circuit then the number will appear then when the buzzer is activated again then it will add and the number will be 2 and so on just like counting system

The number should rest when the switch is close (power off)

I think its simple task but not easy for me

So help please in (the knowledge and connections)

 

[audioguru]

The simple circuit you attached won't time out when a photocell is in the dark.
It also won't count two events when they are close together.
Use the circuit with the CD4093 IC.

 

[ljcox]

The link you posted would work, but it uses TTL integrated circuits.

I don't know why anyone uses TTL these days when CMOS is availabl;e.

I would us the 4026 which is a CMOS Decade counter with 7 sergment outputs.

The dta sheet is attached.

 

[cannibal]

I already bought the IC's shown in that site

please see if this connection attached will work or not

and by the way the circuit without the counter is working just fine

 

[ljcox]

The 555 and transistors must be connected to the 5 Vol;t supply line.

You need a 100 nF capacitor connected between pins 5 & 10 of U1.

 

[cannibal]

Could you please show the connections in the diagram

I am getting confused

and what about the B1 which is 9V