DESIGN 
                  -For my final project i need a proximity sensor which we don't have example for. So i looked for some examples online, most of
 them were complicated i couldn't follow.On this link i found the simplest one, basically it works with ULTRASONIC waves. With both the transmitter
 and the receiver the sensor cant detect the distance of the surrounding bodies. But i couldn't find some of it's components on our inventory
 like the BD135 - BD136 Complementary low voltage transistor and the 300Microhenry Conductor.
                   -As for the conductor it can be easily done with a certain formula find it on that link but as for the transistor it cant be replaced
 with any of those we have in the lab.

                             -So i decided to put that aside and try with a different sensor
for this week but keep researching for my final project. I decided to add a light
sensor to my previously designed board on the eighth week, i edited the EAGLE
file basically to remove both the LED and the switch with their resistors then to
add a PHOTO-TRANSISTOR NPN 1206 along with a resistor to control the current.
 A photo-transistors a component with a direction you will
find the direction in the data sheet of the component.

Finished the PNGs and started milling after that came the soldering everything went fine UNTIL the programing!
 
                                                                                      ERROR
      
       -Each time i run the AT-tiny 44 program on the arduino it gives an error.
 i checked the process all over starting with the last step to find out where the
 problem was. i checked the arduino script then the ISP connections, then the
 board it self. then found out a SHORT CIRCUIT done while milling!!
       -To solve some connections i made a jumper to jump circuit above the
 ground wire to the VCC wire, while milling the machine merged both parts!!
      -With a cutter i carefully separated the connected traces
and with a Multimeter i made sure there's no current is flowing
through
- Then the sensor worked finally and i used it again in the Interface and Application Programming