TeleHealth Hardware: Difference between revisions

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=OLPC TeleHealth Hardware=
{{TOCright}}
==[[User:DyD]] has been working on designing (and learning everything needed to design) a TeleHealth Module for several months==
=The US$10 TeleHealth Module=
===EKG===
* This low cost, multifunction peripheral will provide a means through which the XO can relay valuable medical diagnostic data from the field to doctors many kilometers away.
Simple 3 lead EKG for arrhythmia, murmur, and trauma diagnosis. Also facilitates pedagogical exercises into
* Good documentation needed, possibly via svg/javascript animations.
====Hardware====
* It will compose of a three lead EKG providing valuable information about the heart's electrical status, enabling diagnosis of congenital defects and various arrhythmias.
Currently in design phases
* It will also contain a multipurpose NIR diagnosis tool whose primary function is that of a pulse oximeter, providing information about the oxygen saturation of the blood.
====Main Chipset====
** See nirdiagnositics.com for other NIR functions
The AD8541/2/4 series op-amps fulfill the target specs perfectly.
* The long, time consuming parts
=====Please send an email to "it dot daniher at gmail dot com"=====
** Getting approval from governmental and medical organizations.
====Problems====
** Providing an intuitive interface and a pictograph manual.
* Current problems include tuning op-amps and prototyping.
** Drivers, integration with [[Measure]], and construction of a usable [[TeleHealth Database]].
===Pulse Oximeter===

An invaluable piece of medical equipment relaying information about pulse and oxygen saturation by analyzing the output of two filtered photodiodes in two different frequencies.
== 3 Electrode EKG ==
====Hardware====
* How to do it
Currently nonfunctional: design consists of two MAX4006 OpAmps(Designed for telecom photo-diodes) connected to an IR and a red filtered photodiode outputting a measurable voltage. A finger would be positioned between the photodiodes and a red and IR LED. The pulse oximeter operates on the theory that oxygenated an oxygenated hemoglobin have different absorption and reflection frequencies. The same principle can be applied to any other small organic molecule with identifiable spectra, with proper calibration.
** The first part is the actual hardware part. A circuit, possibly USB powered, using op-amps, would amplify the signal received by the sensor array(of three to twelve electrodes in contact with the skin, in proximity to the heart), to a voltage usable by an ADC. Hospital telemetry units typically use five-lead arrays and derive the standard 12-lead EKG. For diagnostics, the ability to produce a twelve-lead EKG would be infinitely preferable because this is what doctors are trained to read. There should also be at-the-point-of-need instructions for where to place each lead.
====Main Chipset====
** The second part is the safety part, due to the proximity to the heart, strict regulation of leakage current is needed.
MAX4006 Op-Amp
** The third part is adapt [[Measure]] to increase functionality as a [[Telemedicine]] platform.
====Problems====

Once again, op-amp tuning.
*Implementation
===Stethoscope===
** Multiple Op-Amps pick up, amplify, and filter electrical impulses picked up by near-heart electrodes.
A simple microphone and audio amplifier to pick up heart and lung sounds.
*** Older EKGs used suction based reusable electrodes, an adaption of these may be best suited for the third world where replacements are scarce.
====Hardware====
** DyD/DyDisMe has schematics for an EKG using AD620A style op-amps.
* Button Mic
*** 4.1044-7.3 usd
* Audio amplifier
** Ram Dhurjaty, a medical device professional who has had substantial experience with EKG amplifiers, has pointed suggested that there are better amplifiers than the AD620.
* Shielded twisted-pair cable
** Dirakx(Rafael Ortiz) is currently in the prototyping phase of an EKG, to incorporate into the THM, there is now a working protoype, tested with a conventional scope, not tested yet with [[measure]], it needs a GUI for interpreting the EKG data, and also checking for international health regulations and also investigate the overall cost of the proyect.
* Mic plug

===ADC===
== NIR Diagnosis Aid ==
*MCU Specs
* Based on the principles of the differences in absorption of oxygenated and non oxygenated hemoglobin
**Speed: 25+ MIPS
* 800-1000nm light from LEDs are often used in NIR tools
**5 or more channels of ADC
** The most cited frequencies for IR Pulse Oximetery include 805nm, 910nm, and 940nm.
** 940nm IR LED; 12.2c per unit
**10 or 12 bits of ADC
**5V, 100ma or less
* Red light is generated from similar LEDs.
**USB
** 10-20c per unit
**Price, less than 6usd
* Light is picked up by photodiodes, converted to current.
* [[User:Mchua]] and [[User:Nlee]] have offered assistance
* This current is amplified and converted to voltage by a [http://media.maxim-ic.com/images/qv/3760.gif MAX4006] or equivalent chip
* BIG STRUGGLING POINT
** 1.275 usd
* Looking at the C8051F321 until an alternative is found.

==Stethoscope==
===Power Supply===
Due to the nature of medical instrumentation as necessitating high-precision power supply, some combination of a regulator chip, fuse, and smoothing capacitor are needed.
The stethoscope was invented in 1816 by Rene Laennec to avoid having to place his ear to a woman's chest to listen to her heart. Improvements were made in terms of convenience, by adding tubing instead of using a solid wooden trumpet design, but the stethoscope has not changed much since it was invented.
====Main Chipset====

LP2982
Today, electronic stethoscopes are becoming more common, gradually supplanting the conventional stethoscope. The electronic stethoscope provides amplification and filtering, and facilitates connection to external devices for recording and transmitting heart and lung sounds. This is convenient for record-keeping of auscultation findings, and for remote auscultation of heart sounds and lung sounds.
====Hardware====

* LP2982 5, 4.5, or 3v regulator
An example of a modern electronic stethoscope with such a connection is the Thinklabs ds32a stethoscope. This device can connect to laptop computers, as well as iPods and other recorders. By connecting a stethoscope to a laptop or notebook computer, and transmitting sounds, clinics can be set up im remote places for examination of children by a pediatric cardiologist to differentiate between innocent and pathological murmurs.
* Over-voltage protector

** Fuse
Here's an [http://nielsolson.us/MedSchool/stethophone.html example of a electronic stethoscope] that can be built with any stethoscope head, a piece of tubing and a lapel microphone. This particular version uses a battery, but a similar device should be able to draw power from a USB port. The signal is fairly clean, you can hear breath sounds and about halfway through you can hear a playmate giggle in the background, but the signal does require substantial amplification.
* USB Connector

* Shielding
Suggestion: Too much "signal" is probably being lost due to the stethescope head itself. [http://medical-equipment-news.absolutemed.com/2007/09/mp3-recorderplayer-could-replace.html Another bit of research] being done involves using a "cheap" mp3 recorder, pressed directly to the patients chest, to record breath and heart sounds. What about using just small housing around the lapel mike, pressed against the chest? (or indeed, the XO itself?)
===What Can I Do?===

* Provide talent, time, or treasure:
== ADC/DAC ==
** If you have experience designing medical instrumentation, and are willing to mentor or assist high school age students...
* C8051F321 or equivalent chip
** If you have extra time and are able to send emails, track down sample components, or raise awareness...
** A/D 5x10b minimum
** If you don't know what to do with your old soldering iron, oscilloscope, or components collection...
** This specific chip provides A/D 13x10b
* Alternatively a USB micro-controller may communicate with dedicated ADC/DAC chips via PWM, to lower cost.
* Honza Kovar(Jan), from the Czech republic, has acquired development board for the C8051F321 MCU, and will assist with programming and development.

==THDB==
* [[TeleHealth Database]]

== Contributors ==
* Ian Daniher
* Ram Dhurjaty (Simple concept suggested elsewhere)
* Rafael Ortiz
* Steve Burns
* [[User:Sethwoodworth|Seth Woodworth]] (isforinsects)

==Resources==
* http://www.olpcnews.com/use_cases/community/medical_application_community.html
* http://openeeg.sourceforge.net/doc/links-biopsy.html
* http://library.med.utah.edu/kw/ecg/
* http://www.uneca.org/itca/healthport/discussions.htm
*[http://www.thinklabsmedical.com stethoscope]Thinklabs electronic stethoscope for connection to laptop computers.
*[http://swikis.ddo.jp/WorldStethoscope/ World Stethoscope] A universal appliance to get real-time environment data into [[Etoys]]. The original World Stethoscope converts sensor data into sound which is read via a computer's microphone input (hence the name). We intend to use the World Stethoscope's Etoy user interface with the OLPC XO's AD-converter directly.

== See also ==
* [[:Category:Health]]
* [[Vision screening]]

[[Category:Hardware ideas]]
[[Category:Hardware]]
[[Category:Peripherals]]
[[Category:Health]]
[[Category:Feedback]]

Revision as of 23:12, 29 January 2008

OLPC TeleHealth Hardware

User:DyD has been working on designing (and learning everything needed to design) a TeleHealth Module for several months

EKG

Simple 3 lead EKG for arrhythmia, murmur, and trauma diagnosis. Also facilitates pedagogical exercises into

Hardware

Currently in design phases

Main Chipset

The AD8541/2/4 series op-amps fulfill the target specs perfectly.

Please send an email to "it dot daniher at gmail dot com"

Problems

  • Current problems include tuning op-amps and prototyping.

Pulse Oximeter

An invaluable piece of medical equipment relaying information about pulse and oxygen saturation by analyzing the output of two filtered photodiodes in two different frequencies.

Hardware

Currently nonfunctional: design consists of two MAX4006 OpAmps(Designed for telecom photo-diodes) connected to an IR and a red filtered photodiode outputting a measurable voltage. A finger would be positioned between the photodiodes and a red and IR LED. The pulse oximeter operates on the theory that oxygenated an oxygenated hemoglobin have different absorption and reflection frequencies. The same principle can be applied to any other small organic molecule with identifiable spectra, with proper calibration.

Main Chipset

MAX4006 Op-Amp

Problems

Once again, op-amp tuning.

Stethoscope

A simple microphone and audio amplifier to pick up heart and lung sounds.

Hardware

  • Button Mic
  • Audio amplifier
  • Shielded twisted-pair cable
  • Mic plug

ADC

  • MCU Specs
    • Speed: 25+ MIPS
    • 5 or more channels of ADC
    • 10 or 12 bits of ADC
    • 5V, 100ma or less
    • USB
    • Price, less than 6usd
  • User:Mchua and User:Nlee have offered assistance
  • BIG STRUGGLING POINT
  • Looking at the C8051F321 until an alternative is found.

Power Supply

Due to the nature of medical instrumentation as necessitating high-precision power supply, some combination of a regulator chip, fuse, and smoothing capacitor are needed.

Main Chipset

LP2982

Hardware

  • LP2982 5, 4.5, or 3v regulator
  • Over-voltage protector
    • Fuse
  • USB Connector
  • Shielding

What Can I Do?

  • Provide talent, time, or treasure:
    • If you have experience designing medical instrumentation, and are willing to mentor or assist high school age students...
    • If you have extra time and are able to send emails, track down sample components, or raise awareness...
    • If you don't know what to do with your old soldering iron, oscilloscope, or components collection...
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