Noise with the Phototransistor output

[Govardhan]

I implemented the circuit upto the phototransistor(TCRT) part(as shown here http://embedded-lab.com/blog/?p=5508 but removed the 2N3904 and made the 150ohm connection directly to the LED)on breadboard with input supply at 3Vand got the output response of phototransistor as shown in the attached images with the power supply 3V=ON and OFF=0V.The phototransistor collector itself picking up the noise I guess.
Can anyone suggest how to overcome this noise or remove as it will be very tough to simulate the output as the real output of PT itself will be low and this noise addition makes it unfigured.
Thanks.

 

[duke37]

I counted 50 spikes in one second so it looks as if you are not in north america.

The noise should be reduced by careful earthing and screening. Rectifiers should have small capacitors across them to soak up the interference.

Tests with a battery could determine whether the interference is in the power supply or general radiated energy.