Perhaps a DPST switch, one pole for the battery and one pole for the charger?

What DPST switch (an image would help) can I use that once I remove the battery the power is cut off to the circuit.  I was thinking of a relay however it keeps latching which is not good.

Yes it does include a voltage regulator from the charger to the circuit.  However, is this only accomplished with an increase in voltage detection?

I have a circuit that is connect to a battery and a charger
See picture below.




What I need is when I disconnect the battery the charger is also disconnected from the circuit.  How can I do this?

I'm using the analog pin (A0) to control a relay using a power supply and a battery.  The reading is perfect until I remove the battery.  I get noise and numbers are all over the place. 

I want to know what code can I write to detect that the reading has gone berserk so I can notify myself?

Here is the reading below coming out of the serial monitor
498
410
355
969
1023
1023
897
539
438
373
980
1023
1023
719
500
411
356
986
1023
1023
792
516
422
363
967
1023
1023
712
500
409
355

Where did you get the bluetooth module?

Ok it works.  That shows how important a simple capacitor has on a circuit.  I added a 22uF electrolytic capacitor to the rails and it worked.  See picture below.

The Arduino is connected at the other side of the BB - is the power not connecting across to both sides?

Yes breadboard have connecting wires at the bottom to the other rails.  As you can see on picture 3 Im testing the voltage on the opposite side of where the Arduino wires are connected to the rails.

The voltage regulator seems to be working fine because its taking in 9v and converting it to 5 volt but when it goes thru the chip its not outputing the correct voltage.  Why is that?

I have an arduino on a breadboard and having an issue with the voltage on the digital pin 13 outputing an low voltage when connect to a volt regulator.  Why is this happening? because when the breadboard is connected to an Arduino UNO power that is connected to the same power supply it works perfectly fine.  See images and descriptions below.  Thank you for the help.

Notes: Power wires are connected at the bottom of the breadboard
Components:
Arduino on breadboard
Power Jack
9v - 300mA Power
L7805CV 5voltage regulator

Arduino Code:
Set to output LIGHT ON on digital pin 13


The voltage on the rails when breadboard is connected to power is 5 volts


The voltage on digital pin 13 when connected to power is 0.370 volts (why?)

 

The voltage on the rails when connected to arduino power is 5 volts

 

The voltage on digital pin 13 when connected to arduino power is 4.74 volts

 
Why is the voltage on digital pin 13 not the same when connected to an Arduino Uno Power to an Power supply using a voltage regulator?

I'm trying to make a one sided board on Eagle CAD however some of the components pad are on top layer.  How do I change those components to bottom. 

I want the blue pads on the image below to be red.

But is there a way to do it without an SD card?

I'm actually trying to find a way to upload a sketch from arduino to another arduino chip.  Like have one arduino upload the blink sketch to another arduino chip (so it can blink too) without using the computer

Is it possible to upload a sketch to another arduino using just an arduino?

what if you plug a bunch of USB to the computer with different COM.  Is there a way to upload one sketch do different COM connections at a time

Is there a way to upload a sketch to more than one arduino on a breadboard at the same time like the method here http://arduino.cc/en/Tutorial/ArduinoToBreadboard

How do I upload a sketch to an arduino connected to another arduino?