Keys to Successful Medical Practice Design

There has been a quite significant change in thinking and approach over the last couple of decades when it comes to our attitudes to the professions. There was a time when a solicitor was engaged without any cost query and then sent his account once the work had been completed.

It was not regarded as appropriate to ask him to quote for the work in advance and I remember causing considerable offence on one occasion when I asked for a price in advance of preparing the conveyance work on my house sale and purchase.

In like manner, Hospitals and Medical Practices have only relatively recently had to take account of their patients as "Customers", where the customer experience is regarded as an important factor in their overall service.

One significant consequence of this has been an attention to the detail involved in the design of Hospitals and Surgeries which have developed and become much more "customer" focussed. New hospital developments have come to look more like a high class shopping mall and progressively the areas of patient interaction in hospitals and surgeries have endeavoured to become more friendly in appearance.

Much of this move has been really positive as it seeks to establish a more respectful and egalitarian approach between professional and patient/client.

The challenge for the Medical Practitioner or Hospital Developer in this current climate is how to both establish this ambiance within the design of any development, whether minor or more major, and also account for the future - for one thing is certain: change is here with us to stay.

Trends in all areas of business and the professions are developing. If someone develops symptoms then a search on the internet is quite likely to be the first port of call. Likewise with an anticipated purchase. It is an easy first stage to carry out some on line research.

Ultimately, however, if the symptoms dictate, or the purchase need is there, there comes a time when there is no substitute for consulting a professional.

Having an understanding of current and future trends, knowing the detail of building construction, realising the needs of practical and ergonomic working practices, a feel for aesthetics, colour, shape and design are all essential elements of any development plan for Hospital or Medical Practice

Ultimately the only way to achieve the right result rather than end up with a mis-diagnosis is to deal with a professional. What is needful is to retain the services of an experienced and qualified designer who understands the needs from all angles, who accounts for customer experience and ergonomic demands. Who knows about colour, shape, lighting, furnishings such as seating, desking, treatment room requirements, building regulations and all the "professional" understandings that come with the experience of dealing with the needs of the "professional" services.

Ken Rand has 34 years of experience in designing and fitting interiors of Healthcare, Education, Retail and Commercial premises. Visit http://www.kenrandfurniture.co.uk/medical%20/7 to see something of the range of furniture they offer or contact him through http://www.kenrand.co.uk for design advice.

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How DC Micromotors Are Powering Advances in Medical Technology

The field of Endoscopy has been creating new medical techniques to perform minimally invasive procedures. Endoscopy refers to devices, broadly called endoscopes, which allow doctors to examine a patient's internals and perform surgery through the use of specialized, miniature tools instead of using large incisions. These instruments have helped reduce the chance of infection, increased patient recovery time, and given doctors high precision tools for delicate surgeries.

The ability to manufacture tools for complicated surgeries required high precision, miniaturized components. In particular, delivering power to these tools has been revolutionized with the use of DC micromotors.

For a particular example of how DC micromotors are advancing medical technology, take the automated cannula, a handheld device that can take tissue biopsies for cancer detection.

Technology Is Changing Medicine

Biopsies used to be a relatively invasive procedure performed by a surgeon. Incisions large enough to accommodate a surgeon's hand would be made in order to harvest a sample. Now, a cannula can take a series of samples with one single incision no larger than two centimeters and is programmed to be used in the hands of a technician rather than using the limited time of a skilled surgeon. This type of advance is vital to improving medicine for both the patient's care while lowering costs in one of the most expensive healthcare systems worldwide.

The Nuts And Bolts

The ingenuity in this technology is the driver unit. The automated unit is capable of taking samples and moving the probe along three degrees of freedom, doing this all within a two centimeter space while delivering the necessary torque to cut through tissue.

Brushed DC motors were utilized to provide the necessary torque. The use of brushed DC motors enabled the device to generate enough power for all of the cannula functions without compromising the strict size requirement. A compact planetary gearhead connected the power delivery to the cannula head, allowing the probe to rotate the cutter, rotate the outer disposable chamber, and move the cutter down the axis of the probe. The unique design of a planetary gearhead enabled all of these movement patterns to be performed in a miniature package.

Finally, a microcontroller is integrated into the entire system to allow a total programmable, automated sampling process. This flexibility allows the unit to perform any required task and to be adaptable to changing medical practice without undergoing obsolescence. Combined with the miniaturized brushed DC motors and planetary gearhead, this cannula will be able to automate procedures for hospitals.

The tools for automated tissue sampling and biopsies is just one application of how DC micromotors are helping the medical field employ smaller, more powerful tools to compliment their daily operations. These advances are vital to reforming the healthcare system in order to provide care at lower costs and with fewer risks without compromising quality. In the end, patients are the ones who enjoy the end benefits, such as lowered costs, faster recovery times, and fewer complications, of medical technology.

Chris Harmen is an author for MicroMo Medical Solutions, the leading medical industry partner providing DC micromotors and high precision components.

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How Robotic Medical Solutions Can Automate Surgical Procedures

Many surgical procedures require a high degree of precision and a steady hand. Good surgeons practice for years to develop these skills. However, with advances in robotic devices for medical procedures, many medical solutions are being found that do not take up the limited time and expertise of a surgeon. Instead, a good number of tests and minor operations are being carried out by automated devices.

Any surgical device or tool needs to have certain qualities in order to be useful in the medical field. They need to deliver a high degree of precision and accuracy while being lightweight and minimally invasive. Robotic medical tools also need to deliver power in a very compact frame and be able to respond to the environment in which they are working. Hence, these devices require compact, high torque motors to perform operations and servo motors to create a feedback loop to ensure reliability and accuracy.

Case Study - Automated Lung Biopsy

Lung biopsies are performed to sample lung tissue to test for diseases such as lung cancer. The typical procedure calls for a physician to use a CT scanner to manually guide a needle into the lungs. The physician takes a scan and then adjusts the position of the needle. These steps are repeated up to 10 times until the needle is in its proper place and a sample can be taken. This is a long and uncomfortable process for a patient under light anesthesia.

A newly developed robotic sampling device is able to utilize a smaller series of scans and adjustments, typically only four, to automate and accelerate the process. A radiologist can perform this procedure by remote control and reduce the number of total scans, ultimately decreasing the exposure to both the patient and doctor.

System Design

In order to have an automated biopsy robot, many stringent design specifications had to be met. The key to the system is a set of four servo motors that orient the needle, power a pinion drive, and a final motor to rotate the passive roller. Each high torque motor provides a 10 Newton piercing force within a 10 millimeter sized motor coupled to a minuscule 10 millimeter gearbox.

Clearly, delivering a high torque motor that can meet such extreme size restrictions is a breakthrough in servo motor technology. The entire unit is designed to sit on a patient's chest, so the entire device is extremely lightweight. The servo motors combine with a microcontroller to create a feedback system that allows an efficient harvesting process that cuts down on procedure time and patient discomfort.

In the highly complex and technical healthcare field, medical solutions often require serious engineering capabilities. Miniaturized, high torque motors have provided automated tools to facilitate delicate procedures. Saving time and reducing costs while improving patient care is the ultimate goal of any medical solution and is the best way to improve the current ailing healthcare system. The application of high precision components to assist the medical expertise of doctors will continue revolutionize how patients are treated.

Chris Harmen is an author for MicroMo Medical Solutions, the leading medical industry partner providing servo motors and high precision components.

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Choosing a Programming Language for Your Microcontroller

Assembler

Assembler is the most obvious language that you'll consider using as you probably won't need to buy any other tools to use it. More than likely the manufacturer will provide an assembler for the chip and you won't need any books as all the instructions are in the datasheet and you just start coding.

This route to programming is very easy but you may be setting yourself up for problems later on as:

1. It is trivial to write short programs.
2. It becomes progressively more difficult to write large programs.
3. It seems to be the best option as it gives the fastest code.
4. It seems to be the best option as it gives the smallest code.

Assembler: Fast & small code

There is no doubt that assembler gives the fastest and most optimized code (your brain is better at optimization than any compiler!) but assembler is difficult – typically you'll spend ten times as long writing assembler as you would writing in a high level language.

Assembler / Compiler Trade off

This is the trade off; to write the fastest most optimized code or to get the task solved more quickly.

Another problem with assembler is that to do even the most trivial task you have to think about every aspect of the code and all implications on registers and register flags.

Even making a microcontroller perform the most trivial task is difficult e.g. for making a loop in assembler you need to think about which register to use and which instructions all the while thinking about how those registers should not interact with the loop register/other registers etc.

Assembler: Problem - changing the target

Another difficulty is when you change from one microcontroller to another (even in the same device family) the assembler instructions may be changed e.g. more instructions to improve microcontroller performance. So you will have to learn an entirely different instruction set when moving either to a new target microcontroller or moving to a different device within the same family i.e. code re-use is not possible unless you stay with one microcontroller (or devices with a similar internal architecture).

High level languages

HLL: Retarget

Retargeting code to another microcontroller is easier since the HLL will know the details of the new target i.e. instruction set, fuses etc. All you need to worry about is the specific differences between the different microcontrollers (in the same family this will be setting up the internal peripherals).

The important point is that the HLL takes care of the assembler code needed to do the job.

HLL: Easy to understand.

The most useful aspect of a high level language (HLL) is that the language is written in a form you can easily understand – there are no cryptic assembler commands that you have to remember and most commands are made up of several machine code instructions – saving you coding effort (often there are built in libraries of code e.g. LCD driver, Serial port driver, I2C driver etc

So the HLL makes it easy to write code as it generates the correct assembler for the target microcontroller.

HLL : Whitespace

You can also make use of white space (areas of no code) to separate out the various operations within the program – typically assembler code is just one great big list that is really very difficult to read – I know there are comments but you need to comment almost every line so that someone else can

understand the code.

HLL: Task splitting

One of the best features of a HLL is that you can split tasks into separate functions that you can concentrate on them individually (as the HLL takes care of local variables etc.). For assembler even when using a call instruction you have to take care of preserving the register state – in the HLL it's all done

for you.

HLL: Code re-use

Once you learn the HLL you will find it easy to read code written by other people and you will be able to re-use code that you have already written whereas with assembler you will constantly need to analyze the code to see if it fits in with your new functions.

The only decision then is which high level language? There are really three contenders BASIC, C and Pascal – these are the most popular languages and for popular microcontrollers there will be an HLL compiler for each one. I'll just list the advantages and disadvantages of each

BASIC Advantages

1. Very easy to learn and use.
2. A BASIC compiler will produce code that runs fast as a C compiler.
3. Many in built functions (depending on compiler).
4. Very popular – large user base with many example programs.

BASIC Disadvantages

1. Non standard language.
2. If using an interpreted HLL will run very slowly.

Note: Because the language is not standardized it will be difficult to move code to a new processor target type.

Pascal Advantages

1. Easy to learn and use.
2. A Pascal compiler will produce code that runs fast as a C compiler.
3. Many in built functions (depending on compiler).

Pascal Disadvantages

1. Not as popular as C – so not as many compilers.
2. A bit wordy – it was originally intended as a teaching language.
3. Not as flexible as C.

C Advantages

1. Compiled language - always runs fast.
2. Standardized language (ANSI)- easier to port to different compilers / target devices.
3. Many compilers available.
4. Many in built functions (depending on compiler).
5. Very popular – large user base with many example programs.
6. Used in many different industries.
7. Usable at the hardware level as well as higher abstraction levels (although C++ is better for very abstracted programming models).

C Disadvantages

1. Hard to learn at first.
2. Strong type checking means you spend time pleasing the compiler (although this protects you from making errors).

You can find more information from the website here and how to build a website like it here.

Copyright © John Main 2006 Free to distribute if the article is kept complete. http://www.best-microcontroller-projects.com Article Source: http://EzineArticles.com/?expert=John_Main

PIC Micro Hardware Programming Methods

There are three ways to program a PIC microcontroller

1. Using normal programming hardware (high volt programming HVP).
2. Low volt programming (LVP).
3. Bootloading.

The first two methods use the programming port of the PIC microcontroller labeled ICSP (In Circuit Serial Programming).

This port is shared between the existing pins of the microcontroller and after programming the pins revert back to normal microcontroller operation.

Note: To make ICSP work correctly you have to consider the effects and requirements of the ICSP programmer e.g. for HVP a high voltage exists at the Vpp pin (your circuit must be able to handle the high voltage - up to 13V). Also the loading for the other signals PGC and PGD must not be too high i.e. don't put an LED on these pins that uses 20mA - if you did the voltage levels would not be high enough at the inputs to the PIC for programming.

It's fairly easy to design for ICSP use by using isolation resistors to normal circuitry and choosing not to use heavy loads on these pins.

ICSP provides 6 connections from the pic ICSP programmer to your board as follows :

VPP - (or MCLRn) Programming voltage (usually 13V).

Vcc - Power (usually 5V).

GND Ground (zero volts).

PGD - Data usual port and connection RB7.

PGC - Clock usual port and connection RB6.

PGM - LVP enable usual port and connection RB3/RB4.

PIC Micro: High Volt Programming

To use the first method a hardware interface is needed or 'PIC programmer' to interface between the programming software (usually running on the PC) and the PIC chip. This hardware takes its information from the PC via one of three interfaces either:

• The RS232 COM port
• The Parallel port
• The USB port

You choose the interface you want to use and then choose an appropriate PIC programmer. The PC then communicates with the hardware generating the serial (ICSP) signals to translate the PIC hex file into a serial data stream suitable for the target microcontroller.

Note: Almost all PIC microcontrollers use the ICSP interface so once you have a HVP you can program virtually any PIC microcontroller. e.g. you can program 12F675, 16F84, 16F88, 16F877(A), 18F2550, 18F452 etc.

There are several programs for programming PIC micos e.g. ICPROG and many different hardware programmers.

PIC Micro: Low volt programming (LVP)

LVP is exactly the same as HVP except:

• The Vpp voltage is set to the normal supply voltage.
• The PGM pin indicates programming mode.

Note: In this mode you can not use the PGM pin for anything else it is dedicated solely to LVP control.

Devices are manufactured with PGM mode enabled and the only way to turn off the PGM mode is to program it using an HVP programmer.

Note: Some PIC microcontrollers can only use the HVP method since for the LVP method you have to sacrifice one pin - PGM - (to tell the PIC Micro either that it is being programmed (high volts e.g. 5V) or that it is not being programmed (0V) ) and some PIC micros only have 8 pins e.g. 12F675. For this chip the PGM pin is not available so HVP is the only way.

The real benefit of using the LVP mode is that you can program several PIC Micros on a board without having to individually program each one - you could daisy chain each extra micro to a master micro which would then program each one in turn - and this is only possible since the Vpp signal is a normal logic level in LVP mode.

PIC Micro: Bootloading

Bootloading uses any available interface to load a program into program memory. It requires a bootstrap program to interpret the interface data and translate it into program memory instructions.

Note: Note only the newer devices that are capable of programming their own memory can use this method.

Typically a serial port is used for bootloading and the PIC micro bootstrap program will wait for a set time after power up listening on the serial port for a reserved word that tells the bootstrap program to start i.e. it listens for sequence of characters that is not normally used on the interface

Once it receives this sequence it enters bootstrap mode where a hex file is transmitted to the microcontroller over the interface. It interprets this and programs the memory of the microcontroller and then starts the program.

There are two issues with this method:

1. You have to program the bootstrap code using HVP or LVP.
2. It uses up some of the microcontroller resources.

Once programed it provides a convenient way of using the device as you won't need programming hardware anymore and one major benefit is that you can re-program a device without undoing the equipment e.g. if you boxed up you project you could still re-program it using the serial port!

You can find more information from the website here and how to build a website like it here.

Copyright © John Main 2006 Free to distribute if the article is kept complete.

http://www.best-microcontroller-projects.com

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The 12F675 - A PIC Microcontroller Project Guide

The 12F675 is one of the smallest PIC Microcontrollers - it's a tiny device with 8 pins but it's packed with peripherals and it even has a built in 10bit ADC which can read analogue inputs from 4 pins.

It has the following internal peripherals:

1. Two timers.

2. An analogue comparator.

3. 10 bit ADC.

It also has an internal oscillator and internal reset circuit. This means the device uses minimal external components to make it work (other devices require an external crystal oscillator). Of course it also has the usual internal programming memory, EEPROM and RAM needed for programming.

Ideas for projects:

1. 4 channel volt meter.

2. Multi channel Servo controller.

3. Temperature controller.

4. Inductance meter.

5. Touch lamp.

6. Courtesy light time delay.

Note: To get data out of the device you can implement a serial RS232 transmit interface to your PC.

Why use it?
One reason is that because of its size its easy to put into restricted spaces e.g. for a model aircraft or model trains and it's cheaper than the larger devices.

Note: The 12F629 is the same device without the ADC - so it's even more cost effective.

So it's useful in designs that you would not normally think of using a microcontroller for instance you could make a touch lamp dimmer - Note using the microcontroller means you can make far better functionality than using discrete hardware (and even change its programming later on).

With a lamp dimmer you could have an auto off delay function e.g. if no activity for an hour then turn off.

State machines
You could also implement a state machine for more complex control of the functionality e.g. pressing once moves to the next dimming level in the current direction while press and hold changes the dimming direction.

Using a state machine while not trivial lets you control complex operation which you could not achieve (without a great deal of effort) using discrete hardware - and the advantage of using the microcontroller is that if you get it wrong you just re code your software and test it again.

Note: The 12F675 and 12F629 use Flash programming memory i.e. they are re-programmable - you can change their functionality instantaneously with NO re-wiring.

The only problems are:

1. You need to program the device.

2. You need a programming language.

Programming the Device
Surprisingly you can program the device using the standard 4 pin PIC serial interface - ICSP (In Circuit Serial Programming) and with careful design you can even connect your programmer to the same pins that your circuit uses.

Programming language
The programming language normally recommended is assembler and there are good reasons for using assembler - e.g. very fast code and smaller final code size but I would recommend using a high level language such as Basic or C

This is because for assembler you need to work at such a low level that you spend a lot of effort to do trivial tasks and this is better left to the high level language.

For the example mentioned setting up and maintaining a state machine would be extremely difficult in assembler but much easier in C.

Some of the 12F675 projects are available here:12F675 Projects

John Main's website http://www.best-microcontroller-projects.com provides microcontroller resources and free projects which are fully documented including schematics and source code.

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Interfacing a Microcontroller With a PC Using RS232 and the PC Serial Port

Serial Communication

Serial communication is a technique of transmitting data between two pieces of hardware. The smallest piece of data that is transmitted is the byte. A byte is made up of 8 bits. When data is transmitted between two pieces of hardware, the bits are sent one at a time. The hardware sends these bits by sending varying voltages across the wires connecting the devices. The sender and the receiver agree on how often a bit (or voltage level) will be sent.

How often a bit will be sent is referred to as baud rate or bits per second (bps). Then with the help of very precise clocks they can send a series of voltage levels between each other and then reassmble these voltage levels into bytes.

The Problem Communicating Between a PC and a Microcontroller

The RS232 serial port on a PC uses +3 to +25 volts to signify a logic level of 0, and -3 to -25 volts to signify a logic level of 1.

Most microcontrollers use TTL / CMOS logic levels which use 0 to some threshold voltage to signify a logic level of 0, and some threshold voltage to 5 volts to signify a logic level of 1.

In order for the PC and a microcontroller to successfully communicate some logic level translation is necessary.

Using a TTL / CMOS To RS232 Converter

There are many companies that manufacture modules that take care of the required logic level translation. The TTL / CMOS To RS232 Converter is one such module. Typically, these modules connect to the RS232 port on the PC and connect to the microcontroller's transmit and receive pins. Supply 5 volts and ground and you are ready to communicate.

Applications Ideas

Once you have your microcontroller communicating with your PC it opens up all kinds of possible applications ranging from data loggers, pc based oscilloscopes, controlling your pc from your microcontroller, controlling your microcontroller from your pc, etc.

For more information please visit http://www.m5controlsystems.com

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