Help with Firealarm

[likkle]

Ok im creating a school project and am strugling with the circuit

I currently have a

TDA2003V
A Piezo Alarm
LDR
Bulb
LED - For Battery low signal

but im struggling to draw up a circuit design , ive found a diagram on the internet but it has a Chip on board and alot of symbols i dont understand

Can someone please help me out with a circuit diagramme

 

[Nigel Goodwin]

Ok im creating a school project and am strugling with the circuit

I currently have a

TDA2003V
A Piezo Alarm
LDR
Bulb
LED - For Battery low signal

but im struggling to draw up a circuit design , ive found a diagram on the internet but it has a Chip on board and alot of symbols i dont understand

Can someone please help me out with a circuit diagramme

You don't really look to have enough parts there. The TDA2003V is an audio output IC, something like a 741 would be more useful for your purpose.

Presumably the plan is to shine the bulb at the LDR, and trigger the alarm when smoke reduces the level of light from the bulb to the LDR?.

If you give the URL for the circuit you found, perhaps we can help explain it?.

 

[likkle]

https://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt13.shtml

heres what im using i dont understand many of the components on the digram

thankyou

 

[likkle]

**broken link removed**

stars out the url for some reason

 

[likkle]

Why does it do that for?

The one at the top of here

https://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=Fire+Alarm+Circuit+Diagram

 

[likkle]

yes and thats what i want to do

Its just that this diagram seems kinda long winded, i dont really need a CoB the siren i got generates the noise that i need

 

[Nigel Goodwin]

yes and thats what i want to do

Its just that this diagram seems kinda long winded, i dont really need a CoB the siren i got generates the noise that i need

The circuit you have been looking at doesn't look like it would work anyway - the LDR and variable resistor are the wrong way round!.

If you don't need the COB then you don't need the amplifier either, simply use an opamp as a comparator (a 741 would be fine) and use the output of that to switch a transistor feeding power to your siren.

Figure 12 here does pretty well what you are wanting.

 

[likkle]

omg thats brilliant will run this through my teacher tommorow

thankyou very much

This is going to be constructed on a breadboard and i dont suppose you have a "Noob" guide of that those figures scare me

 

[likkle]

Whoops doesnt matter just sat down and read that

gonna go and read this more indepth thankyou

 

[likkle]

Hiya me again ive managed to build the circuit upto the Relay (on that 741 Diagram)

Ive never used relays before and dont know how to ste them out on the breadboard , nor do i understand the relay circuit diagram

up to their im fine (i think

could you please find me a sheet like that opamp sheet , that was very helpfull

 

[Nigel Goodwin]

Hiya me again ive managed to build the circuit upto the Relay (on that 741 Diagram)

Ive never used relays before and dont know how to ste them out on the breadboard , nor do i understand the relay circuit diagram

Relays are very simple devices, electro/mechanical rather than electronic, it's just an electro-magnet (the coil) which activates a switch (the contacts), the connection details should be stamped on the relay, or provided with it. They are also very easy to locate using a meter on the ohms range.

For your application, you could replace the relay directly with the piezo alarm you have.

 

[likkle]

Thanks oki will look into it again, the whole relay thing still puzzles me. Having no teacher is begining to be a real pain

English education ,who would want it

So thanks for being my teacher nigel heh

 

[likkle]

Hello as you can see im very new to electronics (ive had to learn most of it myself )

Now where wud i "Plug In" My Piezo Alarm its go the postivie and negative wires , put i dont see where i plug it in on my board , ive put in the chip and the transistor and what not and that looks ok

Im really stuck on where it has to go

and i also want to fit a switch (which i have) to it , where wud i put that

thanks
likkle