Touch-controlled running water lamp based on ne555 and ls191 counter

Question requirements

1. Competition  question requirements and design plan

( 1) Use Lichuang EDA to design a running water lamp with touch function (5~7 lamps);

( 2) The touch switch is used to switch the effect of the running water light: constant light mode, running water light mode, delayed light off mode

( 3) The touch function can be implemented through the touch module; it can also be implemented using photoresistors, grayscale sensors, etc. If touch control is not possible, use buttons instead of this function.

( 4) Improve requirements: Different lighting indication effects can be produced through external light, sound, temperature and other parameters.

( 5) Other functions

Award information: First prize at school level

Team information: Chen Guoqing, Yin Wei

Instructor; Li Xin

Engineering Analysis:

Implementation of running water lamp: A multivibrator composed of NE555 is used as the signal source to emit a square wave with adjustable duty cycle and frequency. Pin2 and pin6 are shorted together. When powered on, they are both low-level output and high-level discharge tube cut-off. The capacitor is charged through the capacitor between pin1 to pin6 . After full charging, the levels of pin2 and pin6 are pulled high, the output is set to zero, the discharge tube is turned on, and the capacitor is discharged. The reciprocating table outputs a rectangular wave. The rate at which the capacitor charges and discharges (that is, the duty cycle) can be changed by the value of the resistor. Then the waveform is received through the 74LS191 counter, and each high-level counter is incremented by one and then connected to the 74LS138 decoder to decode the binary output into an eight-bit output so that eight LED lights with a common anode can achieve the effect of flowing water.

Implementation of touch light: After powering on, Pin2 and Pin6 are both at high level and the discharge tube is turned on, so the capacitor cannot be charged. At this time, just let Pin2 connect to ground to give a low level by touching it (simulating a real human hand) Touch) Pin2 pulls the output low to 1, and turns on the light-emitting diode through the NOT gate. Then the capacitor is charged through R3. When the capacitor is fully charged, PIn2 is pulled high, both trigger pins are pulled high, and then the output is zero and the diode goes out. It enters the unresponsive state again after power on. Triggering again (that is, Pin2 is pulled low) will again realize the delayed on and off function.