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Medical Electronics / Biomedical Circuits
Medical / Biomedical:  #'s - G       H - O       P - S       T - Z  
Sensors / Detectors -- Main Page -

 

Last Updated: December 29, 2017 03:15 AM

Circuits Designed by Dave Johnson, P.E. :

Alarm sounds when Power Cord is Unplugged - Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries.  However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries.  So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time . . . Hobby Circuit designed by David Johnson P.E.-July, 2000

Circuit Monitors Power Loss - For some medical equipment it is important for an operator to know when power is lost to the machine.  The beeper is powered from a 9v battery and requires the machine to have a power switch with a third set of contacts . . . Hobby Circuit designed by David Johnson P.E.-March, 1999

Corona Monitor - The circuit is powered by +5v and has an on-board voltage regulator as a reference voltage.  The current from a reversed biased photodiode is converted into a voltage using an op amp circuit.  That output voltage is fed to a voltage comparator circuit.  Included is an adjustment in the current to voltage converter, to calibrate the installed circuit . . . Dave Johnson, Lubbock TX (Mar 30, 2010)-DC Magazine - Issue 8 Apr 2010

Fluid_Medical_Detector - A simple 40KHz 12v peak to peak square wave signal generator, using a 555 timer oscillator, was fed to the metal needle and the whole vertical indexing system, which was electrically isolated from everything else.  On the receiver end, a copper foil electrode, which was designed to fit snugly on the bottom of a plastic cup, acted as a holder for the fluid container. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 11 July 2010


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:
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A Low-power Battery-less Wireless Temperature and Humidity Sensor with Passive Low Frequency RFID - This design, featuring the ultra-low-power MSP430 MCU paired with a TMS37157 Passive Low Frequency RFID device can enable a ultra-low power wireless temperature & humidity sensor  (SHT21) . With RFID, applications can benefit from hermetically sealed enclosures by leveraging RFID to provide power and data transmission wirelessly through an enclosure. This design provides complete hardware, software & PC-side software to get you up and running.__ Texas Instruments

Alarm sounds when Power Cord is Unplugged - Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries.  However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries.  So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time . . . Hobby Circuit designed by David Johnson P.E.-July, 2000

Alcohol Level Tester - Yogesh ShuklaA lot of accidents happen every day due to drunk driving.  This is a very useful circuit for testing whether a driver is drunk or not.  The circuit is easy...__ Electronics Projects for You

An Electric Stethoscope - Need to do a bit of self-diagnosis? Make sure your heart is still beating or check other body sounds? Maybe you would like to sort out some unusual rattles or other noises in your car's engine or other machinery? This electronic stethoscope will do the job ? and you can listen via headphones or a loudspeaker.  It has switchable frequency shaping in four bands so you can hone in on sounds which might otherwise be masked out.__ SiliconChip

An inexpensive x-ray machine - Has several x-ray circuits.  Scroll to find this one. 

 Anti-Sleep Alarm - Most of the accidents on highways during night occur due to drivers’ poor vision caused by the continuous exposure of their eyes to the bright light from the headlamps of approaching...__ Electronics Projects for You

Antisleep Alarm for Students - This circuit saves both time and electricity for students.  It helps to prevent them from dozing off while studying, by sounding a beep at a fixed time interval, say, 30 minutes....__ Electronics Projects for You

Bed Wetting Alert - Keep the tide out with this effective bed wetting alarm.  You just add some circuitry to Jaycar's "Secret Farter" and make a sensor.__ SiliconChip

Bedwetting/Wet Diaper Alert SystE - M - Bedwetting is one of the most common childhood problems that can have a significant impact on a child’s health if left unattended.  During the night, the parents would not know if the child has urinated and the kid may sleep all night long on a wet bed, or with a wet nappy.  Bedwetting/Wet Nappy alert system provides a very __ Designed by T.K. Hareendran

Body Weight Scale Reference Design with Body Composition capability and BLE Connectivity - This reference design is for a complete body weight scale end equipment with body composition capability featuring TI signal chain, power, and connectivity components. With TI’s AFE4300 weigh scale/body composition AFE, you can accelerate your body weight scale design or quickly add body composition measurement features to your existing platform. This reference design also includes the full BLE connectivity design for easy interface to BLE enabled smartphones, tablets, etc__ Texas Instruments

Booze Buster Breath Tester - Use this fun device to test your soberity, err sobrity, err how much you have had to drink but dont rely on it to drive.__ SiliconChip

Brain Wave Machine - Humans have been using light and sound to achieve altered states of consciousness for thousands of years.  Primitive cultures used flickering fires and rythmic drumming to induce these altered states.  Today, you can choose from a wide variety of electronic brain-wave machines which use light and/or sound to alter brain-wave activity.  Brain-wave activity ranges from fully awake to deep dreamless sleep.  This activity is categorized into five primary groups: Delta, Theta, Alpha, Beta, and Gamma.   __ Designed by  © Hack Canada

CC2541 Keyfob Reference Design - The Bluetooth Smart Keyfob is a small-form factor, coin-cell powered mobile accessory with buttons, buzzer, LEDs and accelerometer, demonstrating the use of several of the BLE GATT service profiles, like the proximity and battery service profiles.__ Texas Instruments

Circuit Monitors Power Loss - For some medical equipment it is important for an operator to know when power is lost to the machine.  The beeper is powered from a 9v battery and requires the machine to have a power switch with a third set of contacts . . . Hobby Circuit designed by David Johnson P.E.-March, 1999

Convert your smartphone into a pedometer & tracking Device - EDN-Design Ideas 10/22/12    When you go hiking or mountain biking, or simply take a long walk around the neighborhood, you might wonder about the distance you covered or specific details, such as speed.  A specialized device for such a task is an expensive idea.  Now, however, the increasing penetration of smartphones in the market with built-in GPS devices makes it possible to configure a mobile phone to log or send the current readings from its sensors to a server for viewing and processing.   This design idea describes a simple approach to log readings from a GPS using the Python scripting language.  An advantage of Python is that an electronics engineer need not delve into the complex realm of C/C++ calls for Symbian/Android architectures to accomplish this simple task.  All that is required is the installation on a phone of the Python interpreter, along with a text file containing the script.    __ Circuit Design by Ali Asgher Mansoor Habiby and Abdus Sami Abdul Qayyum, Sir Syed University, Karachi, Pakistan

Corona Monitor - The circuit is powered by +5v and has an on-board voltage regulator as a reference voltage.  The current from a reversed biased photodiode is converted into a voltage using an op amp circuit.  That output voltage is fed to a voltage comparator circuit.  Included is an adjustment in the current to voltage converter, to calibrate the installed circuit . . . Dave Johnson, Lubbock TX (Mar 30, 2010)-DC Magazine - Issue 8 Apr 2010

Cranial Electrical Stimulation Unit - Commercial cranial electrical stimulation  (CES) units cost hundreds of dollars but this one is cheap and easy to build.  It is battery-powered, portable and has adjustable current delivery and repetition rate.__ SiliconChip

Cranial Electrotherapy Stimulation (CES) - IC1 forms a narrow pulse, 2.5Hz oscillator feeding IC2.  This chip generates the various timings for the output pulses.  Output is taken at pins 2 & 3 to easily obtain negative going pulses also.  Current output is limited to 600µA by R2 and can be regulated from 80 to 600µA by means of R3.  The LED flashes every 2 seconds signaling proper operation and can also be used for setting purposes.  It can be omitted together with R4, greatly increasing battery life. __ Designed by  © Hack Canada

Cranial Electrotherapy Stimulator - Current flows through clips placed on the earlobes; Output current adjustable from 80 to 600 microAmperes __ Contact: Flavio Dellepiane, fladello @ tin.it

Digital pedometer - Medical and health related electronic circuit diagrams / circuit schematics

Digital pedometer - Pedometer has a range of 9.950 meters with2-digits.  Slip it in pants pocket for walking and jogging __ Contact: Flavio Dellepiane, fladello @ tin.it

Digital Step-Km Counter-Max. Range: 9,950 meters - This circuit measures the distance covered during a walk.  Hardware is located in a small box slipped in pants' pocket and the display is conceived in the following manner: the leftmost display D2  (the most significant digit) shows 0 to 9 Km.  and its dot is always on to separate Km.  from hm.  The rightmost display D1  (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking.__ Learning Electronics

DIY ECG Patient Simulator / ECG Tester - One of the most important test equipment in the biomedical workshop is the ECG Tester or Patient Simulator.  The Patient Simulator is connected to the ECG monitor and delivers the typical ECG signal.  Only with such a tester an ECG monitor can be repaired, the functions and alarm settings checked and loose connections of the patient cables be located.  A Patient Simulators usually costs several hundred dollars and is unaffordable for small hospital workshop specially in developing countries. __ Designed by Frank Weithöner

DIY Lie Detectors - Makezine recently posted a diy lie detector kit that uses your skin resistance  (aka sweat) to detect a lie.  The kit is well explained and consists of two probes you place on your palm with a red/green led readout.  

ECG Amplifier using TLC274 opamp - This circuit allows an ECG signal to be displayed on an oscilloscope.  Opamps IC1a, b and d form an instrumentation amplifier with a gain of 201.  IC1c amplifies the common-mode signal by a factor of 31, and supplies this signal to the right leg.  The first consequence of this is that the body is brought to a defined common-mode level, so that the signal will not lie outside the range of the instrumentation amplifier.__ Learning Electronics

ECG Amplifier with right leg drive - Medical and health related electronic circuit diagrams / circuit schematics

Electronic Muscle Stimulation - This is an electronic muscle stimulator circuit that stimulates nerves of that part of your body where electrodes are attached.  It is useful to relieve headache and muscle pain and revive frozen muscles that impair movement.  It’s mainly muscle stimulation aid is removing cellulitis and build up you muscles.  Can be used __ Designed by Popescu Marian

Electronic Stethescope Amplifier - The post explains how to make an electronic stethoscope amplifier circuit for enabling a loud audible reproduction of the heart beats which is being diagnosed.  The article also reveals how the same can be applied within a cellphone through a wireless circuit

Electronic Stethoscope - Medical and health related electronic circuit diagrams / circuit schematics __ Designed by Aaron Cake

Electronic Stethoscope - U1a operates as a low-noise microphone preamp.  Its gain is only about 3.9 because the high output impedance of the drain of the FET inside the electret microphone causes U1a’s effective input resistor to be __ Designed by Audioguru

ESP SIM Sound Impairment Monitor - The smallest variation in amplifier performance is shown with this simple circuit   __ Designed by Rod Elliott  ESP

Fluid_Medical_Detector - A simple 40KHz 12v peak to peak square wave signal generator, using a 555 timer oscillator, was fed to the metal needle and the whole vertical indexing system, which was electrically isolated from everything else.  On the receiver end, a copper foil electrode, which was designed to fit snugly on the bottom of a plastic cup, acted as a holder for the fluid container. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 11 July 2010

Galvanic Skin Response (GSR) - Medical and health related electronic circuit diagrams / circuit schematics

Guiding Visually Challenged using Raspberry Pi - Blindness is a state of lacking the visual perception due to physiological or neurological factors.  Partial blindness represents the lack of integration in growth of the optic nerve or visual centre...__ Electronics Projects for You


Medical / Biomedical:  #'s - G       H - O       P - S       T - Z  


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