The Design Project
I thought I'd give you all a little update on the design project. I have the presentation on Monday (as previously mentioned). This is the most important event in my academic career so far. However, there are only three design groups in EP and two of them will be sent on to the college-wide competition. Therefore, there's a good chance I'll shortly be doing that presentation (on the 21st) and it will be the most significant academic thingy I've done. Anyhoo, here's some photos of the design so far.
This is our development set-up. The breadboard on the left has all the emitter and detector driving circuitry and the serial cable leads to the probe head (alternately called Fred or Pablo, depends who you ask). The board on the right is the development board environment for the microcontroller.
This is our basic test set-up that was used to produce the signal strength graph posted earlier.
This is the probe head being held over a little sack of 75 microMolar methemoglobin (a haemoglobin compound). We got a fairly strong signal drop-off from it (from 2V on the white plastic reflector down to about 0.6V). The concentration is reasonable for a tumour, but this compound absorbs almost three times more strongly at 950nm than the one we'll actually be looking for. However, creating plain oxidized haemoglobin from this substance would involve much more chemistry than we understand, or have the time and equipment for. Incidentally, does anyone know how to rotate pictures in Blogger?
This is the transparent box for the probe head. One of my group will try to wire-wrap the emitter -detector configuration unto the perforated board on the right. Unfortunately, the lid is fairly thick and only about 80% of the intensity will get through (each way), giving a large drop in the signal.
Here's the wire-wrapped board that we'll soon be testing out. It will replace all of the development set-up in the picture above. We would like to create a printed circuit board, but we definitely won't have time. It's sitting in its case.
Testing: The two peaks represent the signal from emitters one and two, respectively. Remember that they're on opposite sides of the detector. This picture shows the signal when they're both over the white plastic reflector.
Here the first emitter is now over the absorbing surface (notice the intensity drop) while the other one is still over the reflector.
Now both emitters are equidistant from the absorbing surface. This actually corresponds to the detector being directly over the "tumour".
Finally, here's how it looks as the detector continues scanning across the absorber. The first emitter is now over the white reflector while the second remains over the black absorber. The next photo would be identical to the first one.
This is our development set-up. The breadboard on the left has all the emitter and detector driving circuitry and the serial cable leads to the probe head (alternately called Fred or Pablo, depends who you ask). The board on the right is the development board environment for the microcontroller.
This is our basic test set-up that was used to produce the signal strength graph posted earlier.
This is the probe head being held over a little sack of 75 microMolar methemoglobin (a haemoglobin compound). We got a fairly strong signal drop-off from it (from 2V on the white plastic reflector down to about 0.6V). The concentration is reasonable for a tumour, but this compound absorbs almost three times more strongly at 950nm than the one we'll actually be looking for. However, creating plain oxidized haemoglobin from this substance would involve much more chemistry than we understand, or have the time and equipment for. Incidentally, does anyone know how to rotate pictures in Blogger?
This is the transparent box for the probe head. One of my group will try to wire-wrap the emitter -detector configuration unto the perforated board on the right. Unfortunately, the lid is fairly thick and only about 80% of the intensity will get through (each way), giving a large drop in the signal.
Here's the wire-wrapped board that we'll soon be testing out. It will replace all of the development set-up in the picture above. We would like to create a printed circuit board, but we definitely won't have time. It's sitting in its case.
Testing: The two peaks represent the signal from emitters one and two, respectively. Remember that they're on opposite sides of the detector. This picture shows the signal when they're both over the white plastic reflector.
Here the first emitter is now over the absorbing surface (notice the intensity drop) while the other one is still over the reflector.
Now both emitters are equidistant from the absorbing surface. This actually corresponds to the detector being directly over the "tumour".
Finally, here's how it looks as the detector continues scanning across the absorber. The first emitter is now over the white reflector while the second remains over the black absorber. The next photo would be identical to the first one.
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