Wiring Help..

[Code_Nerd]

I have a Home Security project I am doing on a small scale on Veraboard and I am unsure how to Power all of my components..

I have developed the system already on a development board and I am at the stage of soldering everything onto my own board!

I was thinking at first of using an external power pack, however Im not fully sure how this works, my other thought was a 5V and GND rail that I can connect all my components to...

If someone could suggest the best way to supply power for my board it would be much appreciated..
I will need to power the following components:
~ 1 x LCD (No backlight)
~ 1 x 18F458
~ 1 x MAX232
~ 1 x 4050 (Hex Buffer)
~ 1 x 74LS32
~ 1 x 8 Ohm Speaker
~ 1 x Sound chip / device

Regards
Code

 

[JimB]

I was thinking at first of using an external power pack....

A battery would be OK, but you need to be aware of the voltage.
If you are using alkaline cells (Duracell type) your voltage can be either 6v (4 x 1.5v) or 4.5v (3 x 1.5v), and the voltage will vary during the life of the battery.
You could use a voltage regulator (7805), but be aware that you will need a couple of volts to drive the regulator. So your battery would need to be at least 7 volts.

A "Wall Wart" type power supply may be a better choice.
Again you will need a regulator, because the output of the average wall wart is not stabilised in any way and will vary with load.

my other thought was a 5V and GND rail that I can connect all my components to...

I am not sure what you are saying here. Possibly bad terminology.
My first though is yes there will be 5v and 0v rails, they will be powered from the battery/wallwart. They are part of your power distribution, not an alternative power source.

JimB

 

[Code_Nerd]

Thankyou for your reply JimB..

I have decided to go for the transformer option..
My only query is after I have run through the rectifier and regulator can I then create a 5V rail (sorry if term is wrong..) which all my components then connect into? Also I will need the ground created through this circuit..

I hope you understand my terminolgy, my apologies if it is incorrect..

Regards
Code

 

[JimB]

Dont forget the smoothing capacitor after the rectifier!

On your Veroboard, you can select two of the tracks and use one to be the 0volt "rail", and another to be the 5volt "rail".

Then, things which need a 5v supply (eg Vdd of your PIC) will connect to the 5v rail,
and things which need 0v (ed Vss of your PIC) will connect to the 0v rail.

In a simple project like this there is nothing special or magical about the supply "rails".

I hope this helps your understanding.

JimB

 

[Code_Nerd]

Thanks Jim..

I am going to follow the following circuit, it is taken from a schematic of a development board I am using..
**broken link removed**

I wont be using jumpers of course..

Could you please point out where my GND point would be from this circuit?

Regards
code

 

[electica]

Hi Code Nerd, can you show me your schematic diagram?

your help is very much appreciated.

 

[Nigel Goodwin]

Could you please point out where my GND point would be from this circuit?

The six ground symbols at the bottom!.

 

[Code_Nerd]

The six ground symbols at the bottom!.

Yes I realise they are ground Nigel..

However what I am confused about is where is GND? Do I just pick a rail on the board and say "This will be GND??" and connect all my GNDs into it? Or do I need to establish a GND from the "CN1" connector (from schematic..)

Sorry if it sounds stupid, maybe Im having a brain-snap?

Regards

 

[audioguru]

The connector on the left side is from an 8VAC up to 10VAC transformer, not GND. The connector and rectifier bridge can be replaced by a 10VDC up to 12VDC AC/DC adapter. Then the negative wire from the adapter is connected to GND.

 

[Madhouse]

Just connect all your grounds (0v) together. DON'T connect them to CN1!

Alternatively, if you use a wall-wart as a supply, you can ommit DB1 and change E1 to a 1uF, and just connect your grounds to the neg. side of the wall-wart, and pin one of the 7805 to the positive of your wall-wart. Also, ommit E2 and E3, and just de-couple your chips correctly.

That wall-wart can be anything from about 7v to 15v for what you are running, without having to worry too much about a heatsink for the 7805 (a small one is always a good idea though).

 

[Code_Nerd]

Thankyou for all your replies..

I am quite certain I know what Im doing now!

Regards
Code