transcutaneous electrical nerve stimulation (tens)_to print

8/13/2019 Transcutaneous Electrical Nerve Stimulation (TENS)_to Print

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Transcutaneous

Electrical NerveStimulation (TENS)


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Main Points:

1. Mechanism of pain.

2. Functions and features of TENS unit.

3. Circuit Design.

4. Realizing Design into Hardware.

5. Results.

6. Conclusions .


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Mechanism of Pain:

Pain is felt as a result of the brain's response toelectrical (neural) and chemical (hormonal)changes in the body as a result of damage.

Signals from damage or injury are picked up bysensory receptors in nerve endings. The nervesthen transmit the signal via the nerves to spinal

cord and brain.


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Mechanism of Pain:


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Pain Relief:

Pain can be managed in the short term usinganalgesics, but long-term use can be detrimentalto the patient's health.

Side effects of the long use of analgesics mayaffect on liver, kidney or stomach.

In many cases where pain is constant, a medicalpractitioner or physiotherapist may recommendthe use of a TENS unit.

Why TENS?

Because it is safe, effective and virtually with noside effects.


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Features:

1- Two different modes:

a- Continuous (continuous stream)

b- Intermittent (short bursts)

Usually the continuous mode is used but for longterm treatment intermittent mode is used

2- Adjustable.

We can control three variables:

a- Output voltage.b- Width of the pulses.

c- Pulse rate.


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Features:

Continuous Mode: Output Voltage: Adjustable from 12V to 80V.

Pulse Rate: Adjustable from 4.6Hz to410Hz.

Pulse Width: Adjustable between 70 and320 s.

Intermittent Mode :

Duty cycle: 24% at 1.2Hz


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Circuit Design of the Device:

9 volts battery

Step up converter: composed of transformerand DC to DC converter.

Switching oscillator.

Intermittent oscillator.


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Circuit Diagram:


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Realizing Design into Hardware:

Collecting components flight:

We call it flightbecause we had to bring

the components from overseas.Unfortunately the components werecollected from Riyadh, Jeddah, Jordan,

Japan and China.


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Making Project Board:

We connected the components in our project boardas shown in figure to test the function of the circuit.

After that we tested the circuit connections andcircuit output we corrected the faults that raised.


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Make PCB:

We used OrCAD program to make thelayout.


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After that we printed the layout in PCB by

using ultraviolet exposure unit ,then westarted mounting components on the PCB.


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Results:

Continuous mode:

The output volt=79v.

The frequency=362 Hz.


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Results:

Intermittent mode:

The output volt=82v

The frequency=108 Hz.


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Discussion:

Due to the small size and light weight of the TENS device,we think we can integrate it with other medical devices liketherapeutic ultrasound which is used sometimes to reducejoints stiffness.


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Discussion:

In this device there are only two electrodes, sowe think it will be a good idea to double theelectrodes to cover more muscles.


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Discussion:

Placing the electrodes was a little problem forus because the adhesive substance is noteffective for long time ,so we had an idea toimplant the electrodes inside sock to be worn

during the therapy , also make a gloves forhand's muscles.


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Discussion:

This device might be used to treat the face muscles.(Bell's Palsy disease) , This is often due to the partialfacial paralysis that occurs on one side of the face.In thiscase the face muscle is small compared to other muscles,so we need small electrodes to capture the effectedmuscles .


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Conclusions:

We could reach our goals to make a medicaldevice that relief chronic and acute pains startedwith studying the electrophysiologicalparameters, then studying design stages of the

circuit which gives these parameters as output.After that we applied the studies from paper tothe practical work.

During all stages of the project we had to solvesome problems which we got by applying the

designed circuit onto circuit board, we correctedit to get the expected results. Finally, we testedthe output of the circuit by applying the outputdirectly to the muscle.


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transcutaneous electrical nerve stimulation (tens)_to print

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