Questions about DaftMike's Low Battery Indicator

[Crazy Inventor]

So finished building myself a low battery indicator and before I test it I have a few questions.
1) How do I set my potentiometer for the voltage I want my Red LED to come on at?
2) I want your guy's advice on what I have soldered and if it's right.
Here are the pictures.
black on the top is where I'll break the copper connection.
I need to know if it was all right to use a 2N3904 instead of a BC547. Also if you notice I didn't use the same style of board Mike used. His was horizontal lines of copper mine is in a pattern. So do I need to bridge/Break connections of some things here? This is really appreciated.
Edit: For the picture of the back of the board, click the picture to so the notes I made.

 

[ShockSlayer]

Re: Questions about DraftMike's Low Battery Indicator

"Sorry! CrazyInvnetor's uploaded images are not publicly available. "

Also, it's daftmike.

 

[Crazy Inventor]

Re: Questions about DraftMike's Low Battery Indicator

"Sorry! CrazyInvnetor's uploaded images are not publicly available. "

Also, it's daftmike.

Fixed.

Can't find out how to change the settings. So here. If there too big tell me and I'll try to resize them. Not very good with small components, but I think it's good for a first time.

EDIT: Resized

 

[Aux]

1) You set the pot by turning the top thing with a screwdriver or similar. Monitor your voltage with a multimeter and when it reaches the voltage you want the LED to turn on at, fiddle with the pot until it just turns on. You want it to be right at that edge where it turns off if you turn it a little bit less.

2) I will have a look at it when I am not on a phone and can take a good look.

3) That transistor is fine, they are both low-power NPNs and are often substituted for each other.

 

[brunoip]

upload the schematics

 

[Crazy Inventor]

1) You set the pot by turning the top thing with a screwdriver or similar. Monitor your voltage with a multimeter and when it reaches the voltage you want the LED to turn on at, fiddle with the pot until it just turns on. You want it to be right at that edge where it turns off if you turn it a little bit less.

So the pin I left unsoldered is fine unsoldered or does it need to be soldered?
Thanks.

 

[Aux]

Did you just use DaftMike's board layout, despite not having the same tracks on the bottom?

 

[Crazy Inventor]

Yes, but I couldn't find a poteniometer like his with only two pins.

Edit: Scratch that, I re-looked at his plans and his poteniometer has three pins.

 

[Aux]

You kind of can't do that :/ On the back there you've just electrically connected all the wrong things, and more importantly, not connected a lot of things you should have.

You might be able to salvage what you have with a lot of jumpers, but mostly I think you want to resolder just about everything you have there.

Here is a layout I whipped up for you based on the pcb you have. The pink and grey bars are the long strips of copper on the back, and will be power and ground respectively. I forgot to label the LEDs, the one in the middle is green and lower right red. Dots represent where pins should go. A bar with just dots on each end and nothing on the line is a jumper.

 

[Crazy Inventor]

Thanks man I really appreciate it. I'll try it this weekend.

 

[βeta]

Thanks man

 

[ShockSlayer]

Aux needs a sticker on her profile somewhere that says "verified female."

SS

 

[βeta]

One of the admins checked.

 

[Crazy Inventor]

Oh I'm sorry Aux. Though I guess that a title would help.