Difference between revisions of "Spring 11:QRT-PCR"

Revision as of 22:30, 22 March 2011

Looking for weekly reports?

To-Do

• research what to order for heated lid
• fine-tune Steinhart Hart equation using Real Value of R1. also converting to Celsius.

Weekly goals

• 3/25: Optics finished. Code started.
• 4/1: Heated lid finished.
• 4/8: Updated heat transfer function. Successful PCR.
• 4/15: QRT-PCR code finished.
• 4/22: Setup is ready for QRT-PCR. (i.e., the mechanical setup works)
• 4/29: Successful QRT-PCR from the side.
• 5/6: QRT-PCR from the top. Now which one was better?

Heated Lid research notes

OpenPCR first used nichrome wire and silicone tape sandwiched between two plates of aluminum...but it didn't work too well. They said it "smoked and burned out." However, they were designing for 16 samples, not just one (so we won't need to use as much wire). Also, we're not planning on using silicone tape. I still think it's worth trying.

Then they used a peltier device with an aluminum plate + thermal pad.

Another option: using a PCB. Instructions here.

Researching nichrome wire... looks like NiChrome 80 is the best. Here is the datasheet. Now for calculations:

 I = 3A
 V = 15V
 n = length of wire (feet)
 rpf = resistance per foot (ohms/ft)
 
 I = V/R = V/(n*rpf)

 rpf and n are inversely proportional - and cost goes up with rpf. So we want to minimize that.
 reasonable values seem to be:
 rpf = 6.46
 n = 0.77 feet
 which means a 30 gauge wire, d = 0.0100 inches.

Progress Notes

3/22/11

Getting the temperature calculation right earned me a level-up... meaning I got to graduate to the Current Version of the Code. Got a brief intro to it. It's pretty complicated.

Also, ordered the 30-gauge nichrome 80 wire. We'll need about 0.77 feet of it in the heated lid.

3/20/11

Based on model system (blue LED + ND filter), I don't think gain is high enough. Increased gain of transimpedance amp from 2.5e4 to 2.5e5. Well, it didn't help that much. So it's back the way it was. In any case, we get a significant signal (~0.25 units amplitude) with the model system. Huzzah!

After much wrestling with simple math, the temperature sensing is largely working! yay

3/18/11

Optical setup appears to be working.

3/16/11

Added dichroic mirror.

Question: how can I verify the optical setup? it seems to respond to driving signal, not fluorescence.

TODO: put away 25mm lens