InterCom / Door Phone

[Boncuk]

Why do we have 4 months (about 122 days) and 156 posts about this extremely simple circuit??

Hi AG,

please ring the door bell again when we are approaching 300.

 

[Non89]

This is a typical example of "How not to design a PCB".

You're using the wrong layer for the traces. Using the bottom layer (16) for traces and the tPlace layer (21) for components you'll obtain a "look through the board" image. Using the top layer for traces you'll have to solder components from the component side, which is impossible since the solder pads will be obstructed by the part itself.

Using a double sided board with plated through holes the board is easier to populate and solder.

Further there are lots of acute and odd angles in the traces which will most likely lead to unsatisfactory etching results.

Last not least there are components overlapping each other from their size. How are you going to place those properly?

Why didn't you refer to my PCB design? I guess the PCBs are also smaller than yours.


Boncuk

i will turn the tracing paper...


its because your PCBs provided seem cant been edit , some trace are wide , some trace are small ... and my college printer seem cant support to print it... that why i redesign it ....

there wont be overlapping on component, because i was using more larger component's size to design , this is why my design is bigger than yours ....

for the switch , is this leave the no2 no connection?

 

[Boncuk]

i will turn the tracing paper...

Take care to build the circuit mirrored.

its because your PCBs provided seem cant been edit , some trace are wide , some trace are small ... and my college printer seem cant support to print it... that why i redesign it ....

The images provided here were *.gif files. You can't use them to create a board for two reasons: they are not to scale and they have the components. A PCB layout should be printed having the dimension layer (20) the bottom layer (16) and the pads layer (17)

there wont be overlapping on component, because i was using more larger component's size to design , this is why my design is bigger than yours ....

Just check part sizes thoroughly. It's looks ugly anyway.

for the switch , is this leave the no2 no connection?

Yes, pin2 is unconnected. Where would you like to connect it? It's wired as ON/OFF switch!

 

[Non89]

because i was curious about the switch connection you sent me last time... so i just to confirm ....

and i not understand what's the(20), (16) and (17) mean...

 

[Boncuk]

and i not understand what's the(20), (16) and (17) mean...

Layer20 is the dimension layer
Layer16 is the bottom layer and
Layer17 is the pads layer using Eagle.

 

[Non89]

DTDP switch got many type? My DTDP switch is ON, OFF, ON .... when supply to mid(2 & 5) , switch left to on LED on right , Switch right to on LED on left....

and about the circuit.... it only function 1 side , mean when speak on slave's mice, master's speaker voiced .... but when speak on master's mice, slave speaker is silent....

 

[DerStrom8]

DTDP switch got many type? My DTDP switch is ON, OFF, ON .... when supply to mid(2 & 5) , switch left to on LED on right , Switch right to on LED on left....

A DPDT switch is a DPDT switch. Whether it is ON, OFF, ON or ON, OFF, OFF, etc. depends on how you wire it.

 

[Non89]

but if i follow the connection provided, the D1 (silent) cant light up but its just a small problem , the main problem is the circuit can't function well

 

[DerStrom8]

but if i follow the connection provided, the D1 (silent) cant light up but its just a small problem , the main problem is the circuit can't function well

Have you soldered it all to a PCB yet? (without wires all over the place) and in a shielded box?

 

[Non89]

i soldered all component on PCB d , except mice, speaker and switch connecting through wire, i need to confirm it work only can made shielded box ....

 

[Non89]

1)i want to ask , what the purpose of 2.2k ohm resister (R5)
2)the IC is easy get hot after speak, after making the shielded container , the problem can be solved?
3)when speak at mice 1, the voiced out from speaker 2 is not as loud and clear as when speak at mice 2 to speaker 1, any solution can improve it ??

 

[audioguru]

1)i want to ask , what the purpose of 2.2k ohm resister (R5)

It is obvious that R5 is the collector load resistor for both transistors in the first schematic in this thread.

2)the IC is easy get hot after speak, after making the shielded container , the problem can be solved?

The IC should be cool. It gets hot when something is missing or connected wrong.

3)when speak at mice 1, the voiced out from speaker 2 is not as loud and clear as when speak at mice 2 to speaker 1, any solution can improve it ??

The original circuit is perfectly symmetrical with a volume control at each speaker. Maybe the R11 and R18 attenuator attenuates too much.

 

[Non89]

The IC should be cool. It gets hot when something is missing or connected wrong.

i was exactly follow the original circuit now , although the speaker 2 is not clear enough but everything is still work well.... just the IC temperature increasing after voiced out....

 

[Non89]

the master's PCB design as shown

 

[audioguru]

Do you have a TDA7052 or a TDA7052A?
What is the supply voltage?
What is the speaker impedance?
Was the amplifier running a continuous loud tone for a long time?

 

[Non89]

i using TDA7052
the suppy voltage is 12V
the speaker is 8ohm 0.5w
i just closed to normally speak, not even more than 8-10sec.....

 

[audioguru]

The datasheet for the TDA7052 shows a 6V supply when the speaker is 8 ohms. 12V is too high which causes 4 times as much heating as with a 6V supply.

 

[Non89]

oic, thank you ~

hmm.... i think 6V is not enough to support loudly voice.... how many ohms for the speaker i needed to 12V supply? or maybe can try the heatsink as the datasheet listed....

 

[audioguru]

With a 6V supply and an 8 ohm speaker the output power is 1W to 1.2W which is much louder than a cheap clock radio. A door phone is used when the person is directly in front of it so it does not need to be loud.
With a 12V supply then 1W or 1.2W is produced into a 32 ohm speaker.

The datasheet says that with a 6V supply and an 8 ohm speaker then no heatsink is needed.
How can you add a heatsink? It is not made to use a heatsink.

 

[Non89]

oic, i thought heatsink just place closer to the IC ....

i will try the 6V tomorrow ... thank you ~