In this Article Researchers introduced Ball Pen Ink level Indicator(BPILI). In our daily life humans are using pen to write the literature, notes etc. thingsand majority of pens are used in daily life.Every person like students as well as Businesses menuses ballpoint pens for writing. There are different types of penshapes and different colored pens available in market. There are different types of pens are available in market such as Ballpoint pen, fountain pen, gel pen, stylusetc. pens are used. When we all use the pen every time but at some time ink available in the Refill of pen have decreases. But user cannot check the status of ink available in refill every time, because of thick or heavy cover over the refill. When ink level is at the end, the user cannot write a single word at that time user must be change the refill and after that pen may be in use. In this research we focus on that with the help of transistor switching circuit user can know the real time status of the ink level in the refill and before end of the ink in the refill user can be ready to change the refill.

Keywords : Pen, refill, Transistor, LED, battery, connectors.