Sridevi

[K.SrideviEEE]

Hi ! I am studying EEE, we like to do a mini project !!! so we planned to combine Automatic school bell,clock timer circuit,mini ups,multitone siren cicuits together...
Is it possible to do ??? please help me..
if it possible means can u explain what are modifications can be done in the circuit ???

 

[Ratchit]

Sridevi,

Hi ! I am studying EEE, we like to do a mini project !!! so we planned to combine Automatic school bell,clock timer circuit,mini ups,multitone siren cicuits together...

You forget to include GPS, time zone indicator,coffee maker, and mult-band radio.

Is it possible to do ??? please help me..

Certainly it is, if you have the skill and knowledge. Do you? What help do you need?

if it possible means can u explain what are modifications can be done in the circuit ???

What circuit is that. I see no attachment.

Ratch

 

[KMoffett]

Yes, it is very possible to do! First do a complete outline of the project's operations. Block diagrams?...flow charts?..what happens when?...???

Ken

 

[K.SrideviEEE]

Circuits for the our projects !!

these are attachments for our projects... Please tell,what are the changes can we make..

 

[KMoffett]

The first and third images are too small to see clearly. What do you think these schematics have to do with your project? As I said: "Block diagrams?...flow charts?..what happens when?...???". Then find or design circuits that are needed for each part. Interfacing existing circuits can be as big a challenge as designing from scratch. Help us help you.

Ken

 

[mbarazeen]

what do you mean by "combine" ?

 

[ericgibbs]

these are attachments for our projects... Please tell,what are the changes can we make..

hi,
A couple of OP's have already made this version of a school timer.
By changing the transistor/resistor network, on the left side of the circuit, different time periods.
Its a variant of your 3rd one of the images you posted.

 

[K.SrideviEEE]

School bell

hi,
A couple of OP's have already made this version of a school timer.
By changing the transistor/resistor network, on the left side of the circuit, different time periods.
Its a variant of your 3rd one of the images you posted.

ya thank you ! but can you say me how did you calculate that resistor values in this school bell ? because we need 30 mins for lunch hour..

 

[transistor495]

I wondered what project is this 'sridevi'.

 

[ericgibbs]

ya thank you ! but can you say me how did you calculate that resistor values in this school bell ? because we need 30 mins for lunch hour..

hi,
To get a close timing period, its the [total resistance times the 1000uf ] *1.175
The factor 1.175 is derived from experiment in order to adjust for the series transistor.

So for 30 minutes it would be [0.255* 1000 ] * 1.175 , thats a 255K and 1000uF , if you want to have a exact time use a 220K and a 50Kpot in series for the 255K

 

[K.SrideviEEE]

Automatic bell !!!

In this circuit,instead of 230 volts AC bell, can we use any siren circuit of 6-12 v without connecting to the relay ?? reply me please..

 

[ericgibbs]

In this circuit,instead of 230 volts AC bell, can we use any siren circuit of 6-12 v without connecting to the relay ?? reply me please..

You could drive a 12V siren, choose a suitable transistor for the siren current requirement.

Do you have any details for the siren that you could post.?

 

[K.SrideviEEE]

I wondered what project is this 'sridevi'.

Ya this project is about automatic college bell,in which we plan to make some changes like. instead of using AC bell we like to attach multi tone siren,also clock timer is added for switching on the circuit automatically at last we planned to give the supply for all these circuits through mini UPS circuit... so this the brief explanation of about our project..

 

[K.SrideviEEE]

You could drive a 12V siren, choose a suitable transistor for the siren current requirement.

Do you have any details for the siren that you could post.?

ya sure !! this is the siren circuit !!

 

[ericgibbs]

ya sure !! this is the siren circuit !!

If that whole circuit is the siren I would recommend that you use the original circuit relay to switch the siren on.

 

[K.SrideviEEE]

If that whole circuit is the siren I would recommend that you use the original circuit relay to switch the siren on.

can you explain me, why it is better to use siren with relay for this bell circuit ???

 

[mbarazeen]

Ya this project is about automatic college bell,in which we plan to make some changes like. instead of using AC bell we like to attach multi tone siren,also clock timer is added for switching on the circuit automatically at last we planned to give the supply for all these circuits through mini UPS circuit... so this the brief explanation of about our project..

you have generally told about what you are trying to do, we all understand it. but we need your requirement in detail to help in design stage. for example, you said 30min timer. so you need the sirent to continue for 30min? or every 30min it will sound for some time, the timer you are using will be for whole 24 hr so that next day it will continue, or only to stop the alarm/ siren? so how to synchronize the timer to trigger with local clock? what kind of input you will give to your final circuit? (ex enable disable, start, set, mute, auto, manual, bypass..) there a lot of ways you can explain more.

you have to show in a block diagram what it will do/ how it will function, or how will it be operated, like sequence of events.
it will greatly help to give you good suggestions.

 

[ericgibbs]

can you explain me, why it is better to use siren with relay for this bell circuit ???

hi,
Consider how you would control the siren circuit using the relay drive transistor as shown on the original.?

I know that it can be done, but show me how you think it should be done.