User:Pranav Rathi/Notebook/OT/2011/10/11/Device for studying acoustic and mechanical noise in optical setups: Difference between revisions
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==Hardware== | ==Hardware== | ||
The hardware is pretty simple: | |||
# Classic ll S.E. stethoscope by 3M Littmann. This is one of the best in the market used by cardiologists, with nominal price. | |||
# Condenser microphone. I do not the make and model i just bought it online for $.25. | |||
# 3.5mm headphone lead. | |||
# Investigator and helper Lab View V9. Link to download: [https://docs.google.com/leaf?id=0B5jWjFYiQdkfOTkwMjNiNzQtODVlZS00NTc4LWExYTMtNjI3NGE0YjA2NDAz&hl=en_US]. | |||
# Tone generator Lab View V9. Link to download:[https://docs.google.com/leaf?id=0B5jWjFYiQdkfMmRhNzcyMDYtZjM3ZC00MmYyLWE4MjQtZjUwMjBkNThjYWJh&hl=en_US]. | |||
# 5.25" speaker by Virtual Reality Sounds Labs. The speaker has frequency response from 100Hz to 20kHz, which is more than enough for me. | |||
I do not know any specifications about the sound-card and external amplifier i am using to generate the tone of different frequencies. | |||
==Construction== | ==Construction== | ||
==Demonstration== | ==Demonstration== | ||
Revision as of 12:48, 19 October 2011
Introduction
All optical setups are subjected to the mechanical and airborne acoustic noise generated by various electronic and mechanical devices such as computers and air-vents in a lab. Optical setups such as optical tweezers are very sensitive to these noises. Optical tweezers like ours is so sensitive that it almost woke like a microphone. Currently it is reading all kinds of mechanical and airborne noises which are very troublesome for DNA unzipping and overstretching experiments. So I had to do a full scale investigation of these noises[[1]]. To do it I had to create this device: I named it Acoustic & Mechanical Noise Reader (AMNR). This device is nothing but a condenser microphone inside the ear-plug of a stethoscope. But it is so sensitive that it can read the mechanical noise up to -95DB (believe it or not), and it just uses a regular computer sound card with a Lab View V9 program. This whole setup has three parts; AMNR, noise investigator and helper program and, tone generator and speaker.
The whole purpose of this device is following:
- Identify the airborne noise frequencies around the tweezers and their source.
- Identify the mechanical noise (vibrations) frequencies in the optical table and their source.
- Help me chose and design the right setup (stages and sample holders) on the microscope.
- Help me in designing and searching ways to isolate the optical trap form acoustic and mechanical noise.
Most of this I discussed in the “Noise issue with the optical tweezers’’ page of my note book[[2]]. In this page I will just discuss the construction and demonstration briefly.
Hardware
The hardware is pretty simple:
- Classic ll S.E. stethoscope by 3M Littmann. This is one of the best in the market used by cardiologists, with nominal price.
- Condenser microphone. I do not the make and model i just bought it online for $.25.
- 3.5mm headphone lead.
- Investigator and helper Lab View V9. Link to download: [3].
- Tone generator Lab View V9. Link to download:[4].
- 5.25" speaker by Virtual Reality Sounds Labs. The speaker has frequency response from 100Hz to 20kHz, which is more than enough for me.
I do not know any specifications about the sound-card and external amplifier i am using to generate the tone of different frequencies.
