Medical

Electronic I CHING Detector

This circuit is the electronic emulation of the I Ching, a form of divination originating in China. In the classical form, the response is obtained by the manipulation of 50 sticks or, more practically, by tossing 3 coins. The process must be repeated 6 times in order to complete what is called an hexagram. The various combinations given by the 6 readings are then read with the help of a book: the I Ching in fact or book of changes, used as a guide for the interpretation of the results. As the hexagrams look very much like a binary code, with additions and subtractions to go from one hexagram to the other, I thought that a hardware implementation could be feasible. ..

Electromyogram Monitor

Electrical potentials are generated by muscle when there is movement. This Signal can be pick up by electrode to form EMG. For my Final Year Project, I did an amplifier and signal conditioning circuit for EMG. Attached below is the schematics for the Amplifier. Disposable surface electrode are used to pick up the signal. The amplitude of the signal pick up is low, so amplification is needed to measure the detected signal. A differential amplifier is needed because of the high CMRR. 2 electrodes are connected in between the region of interest and the ground electrode is connected to a reference point. ..

FM Electrocardiogram Monitor with LM331/LM231

V_logic is connected to the power supply Vs and all ground are connected to the negative terminal of the battery. Fout is a square wave of varying frequency with a maximum amplitude of Vs. A voltage divider is needed (200k and 10k variable resistor connected in series) is needed at pin 3 to scale the voltage down to around 20 -50 mV. The source-splitting amplifier allows three different potential reference: + 4.5V, -4.5V and Ground. Since the BA1404 can only have +3V as its power supply, we used two diodes to create a total drop of 1.4V and this allows the transmitter to function properly. Another advantage to this setup is that every elements on this circuit can be powered off a signal 9V battery. Although not noted on this schematics, one should know that the input to the transmitter should be on the order of mV (5 - 50mV). ..

Bedwetting (Enuresis) Alarm with 555 timer

A simple two tone water alarm that is light enough to be worn on the upper arm of a sleeper is described. It uses two LMC555 CMOS timer chips followed by a complimentary pair of emitter followers to drive an 8 ohm speaker. Power is supplied by a 9 volt transistor radio battery. An modification to produce a siren rather than two tone operation is discussed. A little experimentation with a signal generator showed that it would be very loud when driven with only 3 or 4 volts between 800 Hz and 3 kHz. I thought about ways to drive the speaker: use an LM324 quad op-amp followed by a pair of transistors, make a transistor multivibrator and have that drive a transistor buffer, make a couple of oscillators with a hex inverter. Just about the, the UPS delivery truck pulled up and I took delivery of a package from Mouser Electronics, which included among its contents, some LMC555N timer chips that I had ordered in anticipation of a very different project. ..

Stethoscope with TL072

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 about 12.2K. C2 has a fairly high value in order to pass very low frequency (about 20 to 30Hz) heartbeat sounds.? U1b operates as a low-noise Sallen and Key, Butterworth low-pass-filter with a cutoff frequency of about 103Hz. R7 and R8 provide a gain of about 1.6 and allow the use of equal values for C3 and C4 but still producing a sharp Butterworth response. The rolloff rate is 12dB/octave. C3 and C4 can be reduced to 4.7nF to increase the cutoff frequency to 1KHz to hear respiratory or mechanical (automobile engine) sounds. ? ..

Here is the inside of the light reflectance sensor (top) and a schematic drawing of it's circuitry (bottom). First, carefully remove the phototransistor as shown. Then, attach the three wires that we will connect to the heart sensor (show in bright yellow). Hint: if you leave the leads from the phototransistor when you cut it off, you can attach the two corresponding wires directly to them, rather than to the circuit board itself. ..

It consisted of 16 LEDs in a circle with two touch pads. By placing your fingers on the touch pads, the circuit started and ran the LEDs in a "chaser" pattern around the display, with a beep each time a LED was illuminated. The circuit gradually slowed down to a random LED and the display showed "how stressed you were." "What a wonderful idea for the 18 LED Display-1" I thought...

This circuit is intended to drive the various lights decorating the crib prepared during Christmas season at many homes in Latin Countries, especially for children delight, in order to obtain realistic light-effects...

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...

Owing to the recent launching in Europe of Cranial Electrotherapy Stimulation (CES) portable sets, we have been "Electronically Stimulated" in designing a similar circuit for the sake of Hobbyists. CES is the most popular technique for electrically boosting brain power, and has long been prescribed by doctors, mainly in the USA, for therapeutic reasons, including the treatment of anxiety, depression, insomnia, and chemical dependency...

Owing to the recent launching in Europe of Cranial Electrotherapy Stimulation (CES) portable sets, we have been "Electronically Stimulated" in designing a similar circuit for the sake of Hobbyists. CES is the most popular technique for electrically boosting brain power, and has long been prescribed by doctors, mainly in the USA, for therapeutic reasons, including the treatment of anxiety, depression, insomnia, and chemical dependency...

This is an image Schematic. No Description available...

Stethoscopes are not only useful for doctors, but home mechanics, exterminators, spying and any number of other uses. Standard stethoscopes provide no amplification which limits their use. This circuit uses op-amps to greatly amplify a standard stethoscope, and includes a low pass filter to remove background noise...

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. A beeper (excludable), signals each count unit, occurring every two steps...

Functions are provided to set the temperature read interval and the FTP interval for upload, The program alters a sample file called base.html and replaces variables in it with information from the PC. When run the program can be minimised at which point it will go to the system tray as an icon. Hovering a mouse pointer on it will display the current reading...