Sensing a closed switch?

[nigelmercier]

Here is a summary of a circuit:

[1] Battery driven, about 9V
[2] Switch to operate a motor
[3] PIC pin triggered when switch operated

Item [3] is an add-on to an existing circuit, so ideally, this would only interface to the battery terminals. I figure I need to sense the current drawn by the motor, or sense the voltage drop.

Any suggestions, or caveats?

 

[ericgibbs]

Here is a summary of a circuit:

[1] Battery driven, about 9V
[2] Switch to operate a motor
[3] PIC pin triggered when switch operated

Item [3] is an add-on to an existing circuit, so ideally, this would only interface to the battery terminals. I figure I need to sense the current drawn by the motor, or sense the voltage drop.

Any suggestions, or caveats?

hi,
Do you like this.?

 

[nigelmercier]

hi,
Do you like this.?

Sadly not

As my OP, I need to only interface to the battery terminals. I can't get to the switched line.

 

[Roff]

Then you need to sense the current. How much current does your motor draw?

 

[nigelmercier]

Then you need to sense the current. How much current does your motor draw?

I'll do some tests and come back ...