How to Make a Obstacle Detector

sense obstacle in path...

Step 1: Material Required

we need
1-photo sensor
1-LEDs
1-battery
1-piece of small wooden slab
some wire for connection
some adhesive ....to fix sensor's

Step 2: Fixing of Photo Sensor

fix the photo sensor in front of led.. as in pic with help of adhesive on wooden slab

Step 3: Connection

connect the photo diode, led,and battery in forward biased.

Step 4: Now Your Photodetector Is Ready

whenever you you put any thing between photodiode and led ....
the led will automatically turn off due to intruption in light..... photodiode conductivity depends on intensity of light..
sorry for any mistakes ...

I can't be able to explain it's ...process

Step 5: