part of project help needed urgent

[lui_23_7]

Hey everyone

I need help on a certain part of my design. Basically what I am doing is trying to monitor the battery voltage of a lithium ion battery. Now when it falls below a certain level or to a certain point say for example 2.9V, I want a device that will detect that the voltage is at a low level and immediately switch on a dc motor. I thought maybe using a voltage comparator to compare the voltage of the battery to a reference voltage set up by the potentiometers but I dont know how to design a schematic that will show what I want. Can someone help?

Thanks
Luis

 

[ericgibbs]

hi luis.

If you Google for:

'Comparator window detector'

You will find many application notes.

 

[audioguru]

Use an LM10. It is an 8-pins IC with an accurate adjustable voltage reference and an opamp that is used as a comparator. It uses a low supply current and operates from a supply from 1.1V to 40V.