long time delay retriggable monostable

[betwixt]

I use a PIC10F200 for a resettable long delay timer. It is cheap, easily available and has a precision internal oscillator so no RC network is needed at all. Works from 2V up to 5V. I use them for delays of up to one month! Current consumption is only a few uA.

Brian.

 

[yassin.kraouch]

I use a PIC10F200 for a resettable long delay timer. It is cheap, easily available and has a precision internal oscillator so no RC network is needed at all. Works from 2V up to 5V. I use them for delays of up to one month! Current consumption is only a few uA.

Brian.

have yo ua link to an evaluation board ?

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When power is first applied to a PIR sensor module, its output goes high, indicating a motion is detected. After some time when adaptation with environment is complete, its output goes low and becomes ready for proper operation. So after power up CD4541B will get a positive pulse at its MASTER RESET input automatically. We dont need AUTO RESET function.



PIR sensor will automatically send the pulse.



In the previous schematic auto reset function was enabled. In CD4541B with 5v supply auto reset function is unreliable and also takes extra current.

I guess the the output of the PIR sensor module is 0-3v (TTL level). You need proper interfacing between TTL output of PIR sensor with CMOS input of CD4541B (one npn transistor, one pnp transistor and few resistors can do the job) . Besides you can also use popular CD4060B instead of CD4541B but you may need some extra components (one diode, one pnp transistor and few resistors).
74HCT series can be directly interfaced with TTL, but unfortunately 74HCT4541 does not exist, but 74HCT4060 does exist.

why you said the PIR will send a positive to negative signal, when its power ON ?
also from where did you get that the level of PIR module is TTL ? what is the problem if we interface TTL to CMOS ?
thanks,

 

[betwixt]

Evaluation board? It's just an 8-pin (6 pin if you use the SMD version) IC. It is a small but powerful microcontroller and extremely easy to program. It has only 256 bytes of ROM and 16 bytes of RAM but that is more than enough to hold a resettable timer program. You don't need ANY external components except a decoupling capacitor across the supply pins so an evaluation board isn't really necesary.

Brian.

 

[ahsan_i_h]

why you said the PIR will send a positive to negative signal, when its power ON ?

It usually does, but can not be proved from datasheet. So I suggest not to use 4541. Use CD4060B / CD74HCT4060. It does not need mandatory reset signal to start counting.

also from where did you get that the level of PIR module is TTL ?

I got it from the datasheet of GH-718C
( **broken link removed** ).

what is the problem if we interface TTL to CMOS ?

if a CMOS (except TTL compatible series) IC is powered by 5v supply, then if you apply any voltage between 3.5v to 5v at any of its input then it will be considered as logic high. If you apply less than 3.5v then it may or may not be considered as logic high. TTL IC can not provide such voltage.

 

[yassin.kraouch]

It usually does, but can not be proved from datasheet. So I suggest not to use 4541. Use CD4060B / CD74HCT4060. It does not need mandatory reset signal to start counting.



I got it from the datasheet of GH-718C
( **broken link removed** ).



if a CMOS (except TTL compatible series) IC is powered by 5v supply, then if you apply any voltage between 3.5v to 5v at any of its input then it will be considered as logic high. If you apply less than 3.5v then it may or may not be considered as logic high. TTL IC can not provide such voltage.

if i understand well, i need to connect AR pin to VDD, and apply a low to high signal in the MR pin when i put power ON ?
that's all ?

 

[ahsan_i_h]

if i understand well, i need to connect AR pin to VDD, and apply a low to high signal in the MR pin when i put power ON ?
that's all ?

Yes. But how you apply the signal? using a switch? it will be laughing.
CD4060B is far better. Actually you will need extra one diode. One or two transistor may needed only to drive LED. If you ask I will post a schematic.

A common PIR sensor module use the ic BISS0001 for amplification and control. The ic has built in retriggerable long duration timer. If you know which R and C is making the time duration, then you can easily achieve 180s time delay by changing the R or C. Also most of the modules have a jumper setting option to select retrigger / non-retrigger function. So you dont need any other ic.
If you have GH-718C sensor module, then you need to solder new resistor to the board. In HC-SR501 sensor module, they have put a variable resistor, so no need to solder, only adjust (300s maximum).

Links:
https://www.mpja.com/download/31227sc.pdf
https://learn.adafruit.com/system/assets/assets/000/010/133/original/BISS0001.pdf