Need Help with constructing egg timer

[eiji116]

i need a build a digital egg timer and the required time will be set on the switches and then timer will be started. At the end of the time period, a buzzer will sound for 2 seconds and the timer will reset

i can only use the following intergrated circuit

4029 - Presettable up/down counter.
4093 - Quad 2 input Schmitt triger.

the time period around 2-10mins and every 1 min interval, so like 2min 3min 4min 5min 6min.........

i know i can use the 4093 to make clock pulse for 2secs interval for the buzzer and 1 min interval for the time period.
I'm having trouble's with 4029 i know i can use the carry-out to trip the buzzer for 2 sec when the time is up, but i don't know really know how to set the counter to counte the time i want like 3mins or 4mins or 5mins

 

[mvs sarma]

after you have come so far perhaps rest of it is only short distance away.

the carry output can be given to an edge triggered monostable whose time can be set to 10sec or 2sec for the buzzer to be powered. at the end of that time buzzer would be off.

 

[ericgibbs]

4029 - Presettable up/down counter.
4093 - Quad 2 input Schmitt triger.

the time period around 2-10mins and every 1 min interval, so like 2min 3min 4min 5min 6min.........

i know i can use the 4093 to make clock pulse for 2secs interval for the buzzer and 1 min interval for the time period.
I'm having trouble's with 4029 i know i can use the carry-out to trip the buzzer for 2 sec when the time is up, but i don't know really know how to set the counter to counte the time i want like 3mins or 4mins or 5mins

Do you have the data sheet for the 4029 counter.?

If you set the 4029 for decimal and as a down counter, you can parallel load the counter with say '1010' [#10]
and use a 1 minute clock from the 4093 to count the 4029 down to zero.

Check the /TC pin of the 4029 for a terminal count of zero.

Is this clear?

 

[eiji116]

"you can parallel load the counter with say '1010' [#10]"

This is the part i don't really get
How to set the bits do i set it with the switch?

 

[ericgibbs]

"you can parallel load the counter with say '1010' [#10]"

This is the part i don't really get
How to set the bits do i set it with the switch?

Yes, you would use a BCD type 'rotary' switch to set from '1' thru '10' minutes and press a switch to parallel load the time value.

The BCD switch is connected to the parallel load pin on the 4029.

EDITED: added a simple drawing showing BCD switch

 

[eiji116]

for calculating the 2sec clock pulse i can use the forkula of T= RC
so 20K resistor and 100uF capacitor should give me 2 sec clock pulse?

is this right????

 

[ericgibbs]

for calculating the 2sec clock pulse i can use the forkula of T= RC
so 20K resistor and 100uF capacitor should give me 2 sec clock pulse?

is this right????

Thats a good starting point, if you use a 100uF cap say, an electrolytic, it could be +/- 20% tolerance!

If you need a clock close to 2sec I would suggest you make the 20K a 50K variable, so that you can trim the time.

 

[eiji116]

Check out the simple sirsuit i have come up with can someone tell what have i done wrong?

now the question is where do iconnect the buzzer?

 

[ericgibbs]

Check out the simple sirsuit i have come up with can someone tell what have i done wrong?

now the question is where do iconnect the buzzer?

hi,
Whats the 4093 osc meant to do?
See my drawing
The 'load' switch is a 'momentary push button', the other 4 switches are latching/toggle normally closed.

Whats the specification of the buzzer and when is it supposed to buzz

 

[eiji116]

just a small regular buzzer 5-15V that will sound for 2sec when the time period ends

i'm trying to use the carry-out to trigger the buzzer for 2 sec but i'm not really quite sure how to do it

 

[ericgibbs]

just a small regular buzzer 5-15V that will sound for 2sec when the time period ends

i'm trying to use the carry-out to trigger the buzzer for 2 sec but i'm not really quite sure how to do it

hi,
The problem with your circuit is the oscillators, they never stop running.

If its a buzzer with an inbuilt osc, that makes a tone when a dc voltage is applied, every 2 secs it will buzz then stop for 2sec and keep repeating forever!

The same applies to the minute osc, its always running!.

You need to construct a latch using a 4093, when the 'load' button is pressed the time switch settings are loaded into the 4029
and the1 min osc starts.

When the /TC goes low it resets the latch and stops the 1 min osc, also /TC going low triggers a 2sec monostable [using 4093s]
and the buzzer sounds for 2 sec.


Is this clear?

EDIT: added an example circuit

 

[eiji116]

yes it make alot more sence to me now
think i can finally get my prototype working
thx for great help

 

[gargi_khullar]

final circuit

I cant seem to access the final circuit diagram that is uploaded above.
Does any1 has it? As it has been deleted from this site.
Could you please send it to me in an email or message it to me.
Thank you so much

 

[ericgibbs]

I cant seem to access the final circuit diagram that is uploaded above.
Does any1 has it? As it has been deleted from this site.
Could you please send it to me in an email or message it to me.
Thank you so much

hi,
I have already searched for the drawing I posted for the OP [22nd Oc2007] and am unable to locate it.
[Requested by a PM from gargi_khullar ]

If anyone else has a downloaded copy, please post it.

 

[ericgibbs]

hi gargi_khullar,

If we have to design a new circuit are any of the following ic devices available in your area.

555, 4017, 4093, 4029. ?

 

[mvs sarma]

hi gargi_khullar,

If we have to design a new circuit are any of the following ic devices available in your area.

555, 4017, 4093, 4029. ?

As these devices are dated 2 decades, perhaps Gargi can source them.

BTW, It has become a culture to hide the name and country of origin. I fail to understand why these people qualify for any help as they don/t have guts to reveal their original identity. There are enough security related issues in some of the topics they seek clarification for. Hope the Site Administrators can allow the the registrations atleast after they declare their country. It would be easy to check them from the internet .

 

[gargi_khullar]

yep i have access to 4093 and 4029

 

[ericgibbs]

yep i have access to 4093 and 4029

OK,

Can you specify the requirements of the 'egg timer' you have in mind.?

example: Timing interval, total time, time out indication [buzzer/LED etc]

A quick sketch would be helpful

Like Sarma, I think its a good idea to fill in your location, so that we know whats available in your area.

 

[gargi_khullar]

the project requires to design a digital egg timer. the required time for example 15 sec will be set on switches and then the timer will be started. At the end of the time period, a buzzer will sound for 2 seconds and the timer will reset and the process will start again. Only the following integrated circuits can be used: 4029 and 4093.

 

[gargi_khullar]

sarma ji

Hi
Well I did not know that it was compulsory to put your country's origin.
Theres nothing to hide in it Sarma, But should that be even necessary. I just registered a day before at this site and did not even get time to fill in every detail.
Anyways but I was just wondering why the country is important? Do you only help people from your country/ from specific countries??
If thatz the case, then it is understandable and I have updated my profile, if it is not what I think then why did it bother you so much??
A polite reply would be appreciated unlike last reply
Thanx