The following are useful links to get us started
- Digikey page listing the existing IR Transceiver part Honeywell HOA1405-1
- Spec sheet for HOA1405-1
- Miller et al, A fiber optic-based system for behavioral eyeblink measurement in a MRI environment, JNeurosci Methods, 141(30), 2005.
This is a partial list of questions to answer:
- Can we use the existing photodiode?
- Ideally, no. Should use an LED with a flat surface. Some fiber optic LEDs already exist.
- How many fibers will we need?
- Will we need special fibers?
- What voltage does the box provide?
- What signal is the box expecting?
- What signal processing will we need to do to the photodiode signal?
Steps Jesse will consider to get us started:
- Generate a research strategy – what steps need to be followed in what order?
- Fiber cable
- connector where the fibers are combined as a ring at the end
- two legs from a bundle
- Fiber cable
- Conduct research into the different possibilities for parts and materials
- Get a basic idea about what kinds of parts will likely work well together
Miller had coupled together these components:
- Optek Technology
- SMA 905 Fiber optic connectors were used, these are industrial standard fiber couplers. $10
- RoMack Fiber Optics
- Fiber Optic Bundles and Arrays, Miller more than likely used a ten and nine fibered, two legged fiber optic array. Pricing may be around 300 dollars. Pricing include the SMA 905 connectors.
- A photometer was used to measure the power of the transfered signal as being less than 200uW to be deemed safe for humans. Priceless
- Resistors and a potentiometer to vary the gain.
- Acid wash, PCB board.
- 7 Pin Mini Din Cable Male
- UA741CN General Use Single Operational Amplifier. Could possible use a nicer amplifier and/or a dual amplifier.
Date: Mon, Feb 25th, 2008
From: Jesse Krigelman
Subject: Fiber Optic Bundled Array
To: Margie Masters @ Romack Fiber Optics
Hello Margie,
First of all, to make it understood. We plan to make around six of these cables. The first one being a prototype that we would like to put together in the next week or so. Just in case you only deal in bulk.
My name is Jesse Krigelman, we had spoken on the phone, I am a student worker at Temple University placed in charge of putting together an apparatus for a professor’s project, whom will be handling funds. So I’m looking to get some type of quote to give to the professor to help make the process go smoothly. I’m an Electrical Engineering major in my final semester, so I’m only partially out of my element on this topic. I just don’t understand some of the lingo.
About:
This project is using fiber optics to transmit and receive infrared light(850nm) being reflected from the eye of a small mouse to monitor eye blinks for an experiment.
Subjects:
I’m looking at putting together a bundled array for an experiment involving small mice. The mice are the size of a typical common/house mouse which limits how much weight that they can support from the fiber optics that will be on their head. The mice will be allowed to freely roam in their enclosure.
Enclosure:
The cabling will be suspended from the ceiling of the enclosure which is approximately two x two x two feet. There will be minimal amount of atmospheric light and no light from the sun.
Apparatus:
The fiber cable will be affixed to the head of the mouse coming from the direction of the tail end of the mouse and attached to a wire hook that will guide the cabling in a gentle curve to the eye of the mouse.
Signal:
The signal being sent is a 850nm infrared signal sent from a Fiber Optic LED from the company OpTek Inc. They offer two packages of types TO-18 and TO-46, I’m not sure if that is something important to either of us. The receiver will be a Fiber Optic Pin Photodiode from the same company. Both have a press to fit opening meant to fit a fiber size of 50/125micrometer.
Known Limitations:
It is understood that the cable can only be curved within a tolerance based on the diameter of the fiber. However, the fiber must make as small a loop as possible to limit the amount of weight extended from the mouse’s head. There will be some distance from the end of the fiber to the eye of the mouse. The acceptance angle must be large enough that a majority of the eye is seen by the fiber without admitting any of the face.
Cabling:
I think that we will probably need no more than nine feet of cable from the fiber array splitter to the mouse and no less than four feet. A circuit box for driving the led can be inside or outside the enclosure depending on the length of the cable used.
My Thoughts:
I’m thinking that the bundled opening will need to be a round type to accept light that will be exiting and entering based on the reflection of infrared light cast onto the eye. I will need two legs from the bundle, one for input and the other for output of the infrared signal. I would assume that we would not need a very large bundle, nor would we need a very thick insulator since there is not much light to speak of on the end of the connector that is inside of the box with the mouse.
If you need to reach my by phone I have hours between 1240 and 430 Mon-Fri except Thur @ (610)764-5422
Thank you for your help,
Jesse Krigelman
jesse.krigelman@temple.edu
