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Biomedical sensors

Biomedical sensors. Done by:. Aya Emad 074015 Nada Hashim 074087 Fatma Alhag 0740 Razan Gaafar 074035. Introduction By: Aya Emad. WHAT IS THE SENSOR?. WHAT IS THE BIOMEDICAL SENSORS?. TYPES OF SENSORS.

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Biomedical sensors

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  1. Biomedical sensors

  2. Done by: AyaEmad074015 Nada Hashim 074087 FatmaAlhag 0740 RazanGaafar074035

  3. Introduction By: AyaEmad

  4. WHAT IS THE SENSOR?

  5. WHAT IS THE BIOMEDICAL SENSORS?

  6. TYPES OF SENSORS

  7. Biomedical sensors are the same as the normal sensors but the difference in the applications we use it in.

  8. Requirements of biomedical sensors:

  9. Biopotential measurement By Nada Hashim

  10. BIOPOTENTIALS Electrical signals induced by body organs. Vital clues as to normal or pathological functions of the organs.

  11. THE ORIGIN OF BIOPOTENTIALS At cellular levels The electric potential across a cell membrane is the result of different ionic concentrations that exist inside and outside the cell.

  12. Features of biopotentials • Small amplitudes • Low frequency range of signals Presence of biological interference and noise.

  13. The Principles of Biopotential Measurements The unique features of biopotentials led to a unifying principles of measurement, it includes: -Electrode design. - Amplifier circuit design. - Good measurement practices.

  14. Electrodes • The electrode is secured to the skin by means of non-allergenic adhesive. The electrode is connected to the external instrumentation typically via a snap-on connector.

  15. SILVER-SILVER CLORIDE ELECTRODES produce the lowest and most stable junction potentials Electrodes for BiopotentialRecordings

  16. Gold Electrodes advantages of high conductivity Electrodes for Biopotential Recordings

  17. Electrodes for Biopotential Recordings readily used although they have a much higher resistivity and are noisier than Nobel metals.tal electrodes

  18. Necessary enhancement: Amplification:

  19. Filtering Can be done by : • Small inductors in the lead wires. • Small capacitors between each electrode lead and ground. Bandwidth limitation can be imposed at each stage of the amplifier.

  20. Electrical Isolation(patient protection): • Patient safety must be ensured to reduce the prospect of leakage current to the Earth ground of the instrument being tested (could be fatal). • Can be done electrically or by optical isolation..

  21. Skin preparation and electrolytic jell Skin preparation: due to potentials existing at the skin surface. Electrolytic gel: Important in maintaining a high-quality interface between the electrode metal and the skin.

  22. Example of a biopotential sensor: ECG An ECG is used to measure: • Any damage to the heart. • How fast theheart is . • The effects of drugs • The size and position of the heart chambers

  23. ECG The heart muscle: likened to a simple pump, this pump moves over a gallon per minute, about 1900 gallons a day, over 700,000 gallons per year !!!!

  24. Electrical activity over a heart beat: The heart contains 4 chambers the atrium( left and right) and the ventricle (left and right) • The SA node (nerve) cause both atria to contract. • Electrical impulse travels to the AV node(node) and where it branches to left and right ventricles cause them to contract and squeeze blood to the body.

  25. Acquiring ECG signals • ECG signals are acquired by placing electrodes directly on the torso, arms, and legs . • A clinically accepted lead system has been devised and is called the 12-lead system . It comprises a combination of electrodes taking measurements from different regions designated : limb leads, the pericordial leads, and the chest leads.

  26. Blood pressure measurement by Fatima Alhag

  27. The origin of blood pressure is the pumping action of the heart. • The highest value ,systolic (sp). • the lowest value ,diastolic (dp). • Pulse pressure (PP) is: PP = SP – DP

  28. Measurement Techniques Indirect Blood Pressure Measurement: Method: • Auscultatory Method . • Oscillometric Method.

  29. Oscillomtric method:

  30. Sensors: Strain Gauges:

  31. Piezoelectric sensors:

  32. Direct Blood Pressure Measurement: • Catheter–Tubing–Sensor System:

  33. Pulse oximetry & glucometer By RazanGaafar

  34. Pulse oximetry is a simple non-invasive method of monitoring the percentage of haemoglobin (Hb) which is saturated with oxygen.

  35. Contents: • Probe:

  36. Display:

  37. Each hemoglobin molecule can carry up to four molecules of oxygen.

  38. Measurement PrincipleBlood rich in oxygen absorbs infrared light and lets red light pass through.Deoxygenated blood absorbs red light and allows infrared light to pass through.

  39. Circuit diagram:

  40. How to calculate the oxygen saturation?

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