Medical

This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles` stimulation and invigoration but, mainly, it could be an aid in removing cellulite. Tape the electrodes to the skin at both ends of the chosen muscle and rotate P1 knob slowly until a light itch sensation is perceived. Each session should last about 30 - 40 minutes...

Commercially available hearing aids are quite costly. Here is an inexpensive hearing aid circuit that uses just four transistors and a few passive components...

Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie...

The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1). This circuit is based on the fact that a person`s skin resistance changes when they sweat (sweating because they`re lying). Dry skin has a resistance of about 1 million ohms, whereas the resistance of moist skin is reduced by a factor of ten or more...

Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie...

Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie...

This circuit was developed since a number of visitors of this website requested a timer capable of emitting a beep after one, two, three minutes and so on, for jogging purposes. As shown in the Circuit diagram, SW1 is a 1 pole 9 ways Rotary Switch. Setting the switch in position 1, the Piezo sounder emits three short beeps every minute. In position 2 the same thing happens after a 2 minutes delay, and so on, reaching a maximum interval of 9 minutes in position 9...

Senses heart pulse by means of an infrared earlobe clip. Reverse engineered circuit diagram of heart pulse sensor circuit board out of a treadmill. Notice that the output is level shifted for use by CMOS logic running on 4.5V regulated down from the 6V battery. The CMOS logic also controlls the power to the analog circuitry and infrared LED...

Sound effects generators trying to imitate rain sound or sea surf are well known to hobbyists from many years: their purpose is to induce relaxation and sleep or to help in concentration and study. The sound generated is restrained to a background level and these devices are frequently kept on the night table...

This circuit was designed to detect the approximate percentage of salt contained in a liquid. After careful setting it can be useful to persons needing a quick, rough indication of the salt content in liquid foods for diet purposes etc...

Here I describe a little electronic device that detects snoring. The principle though very simple is efficient and well protected against false triggerings. Upon detection, it generates a noisy and painfull alarm. Just what`s necessary to wake up everybody except the snorer...

The idea behind this snore alarm, is just to rouse the snorer, not the entire household. To wake the sleeper, vibration is used, not an audible alert. The vibration is provided by a small motor housed in a small 35mm film case, which can be placed under the sleepers mattress or pillow. This circuit has a level control and peak display indicator, a variable trigger threshold and trigger indication...

This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types (see table). A Photo resistor extends the preset time value according to sunlight brightness (see table)...