Light based transducer

I have begun work on a new light based transducer for my project. Hope this will work better using the Everlight PT204-6B phototransistor and an LM 325 op-amp.


Optical sensors and What-not

After some more research I came across the following websites which offer pulse detection solutions:

Clearly optical sensors are more widely used for detection.

Correction: Device not working

Today I spent a lot of time debugging my device and found out that my device is not functional. I realized that I made a mistake in reading the schematics and placed the stuff that was meant to be on pin number 5 on pin number 8. After fixing this I still find that the device is not working. I troubleshoot the piezo-electric film and find that its working, so I use an audio-jack as a wave-form generator and oscilloscope. I also found that I will need a capacitor to bypass the ports one and eight to get the required output for pulse. At the end of all the troubleshooting I find that my Op-amp is fried.

Device is working

The pulse collection device is now working, however my PC’s audio card is refusing to accept as an audio device. One thing that could be a cause is that I may need a second stage amplifier. I came to the conclusion after using a multimeter to measure the voltage. The multimeter seems to respond to me when I hit the piezo film however the output voltage is very low. This is a major set back in my project as I need a working device in order to collect pulses for my report.

Meeting #2 with supervisor

I have completed my 2nd meeting with my supervisor. The outcomes of todays meeting were:

  • Power and test the device.
  • Do some research on pulse and its uses.
  • Start design specification for the report.
  • Decide on date for next meeting.

My plan is to complete the power on of the device by 30th of august. Complete research on pulse by 7th september and complete the first draft of my specifications by 14th september.