What is the delay operation of the delay light touch switch
Release time：2018-07-09 Clicks： Click
How can we use the delay touch switch to achieve the delay function? This operation is not so simple. Please follow our instructions and learn together.
The delay touch switch circuit has been widely used in digital products such as telephone, cell phone and electronic dictionary. RS flip flops, counters, and 555 integrated circuits are generally used. In some practical applications of electric toys, the above way of realization will increase the complexity of the whole circuit, and can not achieve simple and practical results.
This article will introduce a variety of digital products that can be used in electric toy circuits, which are widely used in telephones, mobile phones and electronic dictionaries. RS flip flops, counters, and 555 integrated circuits are generally used. In some practical applications of electric toys, the above way of realization will increase the complexity of the whole circuit, and can not achieve simple and practical results. This paper introduces a simple and stable touch sensitive single key switch circuit which can be realized in the application of single chip microcomputer.
A simple and stable touch sensitive single key switch circuit is realized in application. 1 it is easy to see that the Q1 connection will consume a certain amount of power when handling the Vin connection mode. A way to reduce power consumption is to connect the Vin directly to the battery, which can be grasped according to the circuit. 2 the role of capacitance C1 for the general electric toys, there are BOD (Brown-downDetection) circuits inside. This circuit has a low voltage detection function: when the input voltage changes from high to low, the electric toys will be reset automatically. When you want to turn off the machine, press S1, and the output of the electric toy is low. After the key is lifted, the Q1 and Q2 are cut off, and the singlechip is powered down. However, when the BOD circuit of the MCU detects that the voltage of the single chip microcomputer is suddenly reduced, the single chip will be reset, and the I/O is set to the pull up state, the Q1, the Q2 and the guide circuit are opened again. 3 circuit principle DC socket is a DC regulated power supply chip with shutdown control end, MCU is a single chip microcomputer.
When S1 is pressed, Q1 and D1 will operate, and the voltage regulator chip will work to supply power for singlechip. The electric toy immediately sets the corresponding I/O pin to high output, when Q1 and Q2 are turned on, and the whole circuit is in working state. After that, the I/O pin is set as input, and the Q1 and Q2 are connected as a result of the presence of R4. Electric toys always scan the corresponding I/O input state. If S1 is not pressed, the I/O will always be high. When the S1 is pressed down, the D2 is on, the electric toy detects the low input of the I/O pin, and the electric toy sets the I/O to a low output state. Q2 cut-off, if the button is lifted, the Q1 will also be cut off. The voltage regulator chip will not provide voltage for the electric toy, and the whole circuit is in the off state.
The values of the R3 and the pull resistance R4 are in some electric toys, such as the series of the AVR series electric toy linkage, with the internal pull resistance Rpu, as shown in Figure 2. The electrical resistance can be controlled by the electric toy program, so that no external pull ups are required.
Under normal circumstances, the value of R3 is much larger than R4, otherwise the input voltage Vpin of I/O will be lower than the lowest value of standard input voltage VIH. From the linked series toy data manual, we find that the value of Rpu is between 20K and ~100k, and the minimum value of VIH is about 0.6VCC. So R3/ (R3+R4) >0.6, take R4=50k Omega, and take R3/ (R3+R4) =0.8, so the value of R3 should be in the range of 200K Omega, we can choose specific R4 value according to the actual working condition.
Delay time delay handling of switch switchgear. In some specific applications, such as mobile phones and other digital products, the switch machine needs delay operation. A simple way to achieve this is to start counting when the button is pressed, until the key is lifted. Only this meter is large enough to allow it.