Digital Bike Tachometer SP

This digital SP tachometer for bikes uses 2 reed switches to urge the speed data of the bicycle. The reed switches are put in close to the rim of the wheel where permanent magnets pass by. The permanent magnets are connected to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed.

The tachometer circuit works in step with this principle; the pulses created by the reed contacts are counted inside an explicit time interval. The ensuing count is then displayed and represents the speed of the bike. 2 4026 ICs are used to count the pulses, decode the counter and management 2 7-segment LED show. RS flip-flops U3 and U4 perform as anti-bounce.

Electronic bicycle SP tachometer circuit diagram

The pulses arrive at the counter’s input through gate U7. The measuring amount is set by monostable multivibrator U5/U6 and might be adjusted through potentiometer P1 so the tacho are often calibrated. The circuit U1/U2 resets the counters.

Since batteries are used to power the circuit, its not sensible to support the continual show of speed data. This circuit isnt continuously active. The circuit is activated solely once a button is pressed. a minimum of 3 permanent magnets should be put in on the wheel. The circuit are often calibrated with the assistance of another pre-calibrated tachometer.

 

 

Streampowers

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SP LIE DETECTORS

LIE DETECTOR-1

This circuit detects the resistance between your fingers to provide an oscillation. The detection-points can detect resistances as high as 300k and because the resistance decreases, the frequency increases.

Separate the 2 bit pads and fasten them to the back of every hand. because the subject feels nervous, he can sweat and alter the frequency of the circuit.The photos show the circuit engineered on computer boards

with separate bit pads.

LIE DETECTOR-2

This circuit detects the resistance between your fingers to turn on the FALSE LED. The circuit sits with the TRUE LED illuminated. The 47k pot is adjusted to permit the LEDs to change state when touching the

probes. 

LIE DETECTOR-3

This circuit detects the resistance between your fingers to show the four LEDs. As you press tougher, more

LEDs are illuminated.

LIE DETECTOR-4

his circuit detects the resistance between your fingers to show the 3LEDs. As you press harder, a lot of LEDs are illuminated. Thecircuit is less complicated than Lie Detector-3. 

 

 

 

http://streampowers.blogspot.com/2012/07/sp-lie-detectors.html 

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