introduction Taking care of small babies is very tiring, because they wake up and sleep more frequently, and activities such as feeding and changing clothes will take up a lot of time and energy for adults. The birth of the cradle has greatly reduced the burden on adults, but there are still many unsatisfactory places. Using an action (acceleration) sensor and a feature-rich microcontroller, you can design a relatively intelligent cradle. background Nowadays, the electric cradle on the market has only a simple timing function, so it cannot act against the activities of the baby. If the cradle is shaken all the time, the comforting effect on the baby will be reduced. The automatic cradle triggered by sound has the disadvantage that the baby is active first, and if it is not pacified, it will cry, the cradle will start to appease; and if it is crying for other reasons, the cradle can not help. Therefore, it is more appropriate to control the cradle according to the baby's activities. Freescale's accelerometers offer excellent performance and low cost for such applications. Principle of automatic cradle This system uses Freescale MC9S08QG8 microcontroller as the controller, uses Freescale acceleration sensor MMA7260QT to judge the baby's activity, and uses the microphone to detect the baby's crying sound as an auxiliary judgment, and then starts the cradle shaking according to the setting. The human machine interface consists of a keyboard and a dot matrix liquid crystal display. Method of measuring motion There are many algorithms for measuring the motion and motion of the accelerometer. In this system, since the moving direction of the cradle is two-dimensional, and it is mainly one-dimensional (so a one-dimensional accelerometer can also be used), the motion is single and the occasion is not complicated. Therefore, a simple threshold judgment method can be implemented. The threshold represents the sensitivity and can be selected by the user according to the actual situation. Touch button implementation The touch button is a popular technology in recent years. Since the MC9S08QG8 MCU has a very low port leakage current and a powerful keyboard interrupt function, it can be realized without adding other active devices. And the system uses two ports to provide the function of three buttons. The PCB pad is used as a touch button, and a small capacitor C1 is formed between the ground and the ground (when no finger is touched), and the button is grounded through the large resistance resistor R1. The MCU port usually outputs a high level. When the button is detected, the keyboard is interrupted. As the charge on C1 is lost through R1, the level is gradually reduced until the keyboard is interrupted. The time from the start of detection to the keyboard interrupt is T1, when there is a finger. When touched, it is equivalent to a capacitor on C1. Therefore, when the capacitance value becomes C2, the time from the start of detection to the keyboard interruption is T2. By detecting the difference between T1 and T2, the button press can be judged, as shown in Fig. 1. Assuming that the capacitance of the button 1 is C1 and the capacitance of the button 2 is C2, if C1 is increased by C2, the button 1 is pressed. If C2 is increased by C1, the button 2 is pressed, if both C1 and C2 are similar. The value can be judged as the button 3 is pressed. The button 3 on the PCB is located between the button 1 and the button 2. This realizes the function of two ports to judge three buttons. PWM pulse width modulation drive motor The motor is driven by pulse width modulation (PWM) to achieve speed regulation. The user can select the 3rd speed of shaking, and can also implement soft start and soft stop. LCD The 3V serial port LCD display module is driven by the SPI port of the single-chip microcomputer to realize a simple and efficient display interface. System characteristics A. Using Freescale MC9S08QG8 microcontroller as the controller, the integration is high and the cost performance is good. B. Using Freescale's MMA7260QT accelerometer to sense motion, advanced performance and stability. C. A good human-machine interface includes a dot matrix liquid crystal display and a simple menu system. D. Use the low leakage current characteristics of the microcontroller port and the keyboard interrupt function to implement the popular touch button technology. E. Use the single-chip PWM function to achieve adjustable cradle speed, soft start and soft stop. F. Music playback function with controllable volume. System Overview The structure of the automatic cradle control system based on the MMA7260QT acceleration sensor is shown in Fig. 2. When the baby is asleep, the cradle does not move, the output of the acceleration sensor is stable, and the value obtained by the single chip sampling is taken as a zero value. When the baby has motion to cause the cradle to shake, the value obtained by the single-chip sampling changes, and when the change is greater than the set threshold, the PWM pin output drives the motor to operate. The microphone is also input to the microcontroller as an optional auxiliary judgment. Music playback is an optional secondary comforting method. System hardware The circuit block diagram is shown in Figure 3. Freescale MC9S08QG8 microcontroller The system uses MC9S08QG8 as the core controller. Its highly integrated functions and flexible port control greatly simplify system design and cost. The system mainly uses the following functions: High-speed CPU and large-capacity flash and RAM memory Built-in precision clock 2-channel 10-bit AD converter 2 keyboard interrupt input ports PWM output function High speed SPI interface Freescale MMA7260QT three-axis accelerometer The system uses the new MMA7260QT triaxial accelerometer as the main sensor, internal signal conditioning, built-in filtering, range selection, stable and reliable performance, and the design is quite simple and convenient. Acceleration measurement section The sensor is set to the minimum range, and the output is filtered by the resistor and capacitor and then enters the AD input of the microcontroller, as shown in Figure 4. Keyboard circuit The keyboard circuit is very simple, the port can be connected to the 2M resistor, and the PCB design of the touch keyboard should take into account the three-key judgment, so the design is as shown in Fig. 5. motor driven The single chip outputs a PWM pulse width modulated signal and then drives the motor through a drive circuit. Microphone input The microphone input is amplified and rectified to the capacitor through a diode. This voltage enters the microcontroller AD converter. play music The music source uses a dedicated music IC, and the power amplifier uses National Semiconductor's LM4874 chip, which has a 4-level electronic volume adjustment function. This system requires only mono. LCD Using 3.3V serial liquid crystal display module, 128X64 dot matrix, the microcontroller is directly connected through the SPI port. Other peripheral circuits The power supply is converted to 5V by 220V and then regulated to 3.3V output by the LM1117-3.3 to the system circuit. The 5V voltage is also used to drive the motor. system software The system software performs the following functions: The cradle status is periodically checked based on the set parameters. Periodically check the charge and discharge time of the keyboard interrupt pin. Drive the LCD display to display related parameters and menus. The music is driven by the cradle according to the parameters. Detecting cradle status The acceleration sensor is detected at a frequency of 10 Hz, and the timer interrupt program starts the AD converter. When the AD conversion is completed in the main program, the result is saved, and compared with the zero value, if it is greater than the threshold, the baby is considered to be active, and is activated according to the setting parameter. Motor, music. Keyboard detection The keyboard is scanned at a frequency of 20 Hz, and the timer interrupt program sets the corresponding pin as an input, allowing the keyboard to be interrupted. The pin discharge causes a keyboard interrupt, saves the timer value at the time of the interrupt, and then exits. After the main program and other two button pins are scanned and the discharge time is saved, the keyboard processing program is called to analyze and obtain the result of the button. LCD driver The LCD monitor uses the SPI port to send data, and adjusts the contents of the LCD display according to the result of the button. Cradle drive and music playback When driving the cradle, start the PWM output according to the setting parameters, record the time, and slowly stop the cradle after the specified time (reduce the PWM duty cycle). The power amplifier volume triggers the music IC to play music according to the parameter settings. Other auxiliary programs According to the software requirements, set the timer interrupt and the variable TIme_to_1s, and reset the variable when the value in the variable reaches 1S. Program structure The main program flow is shown in Figure 6. The production process of a machine is the whole process of making a product from a raw material (or semi-finished product). For machine production, it includes the transportation and preservation of raw materials, preparation for production, the manufacture of blank, the processing and heat treatment of parts, the assembly and debugging of products, paint and packaging. The content of production process is very extensive. Modern enterprises use the principles and methods of systems engineering to organize production and guide production, and regard the production process as a production system with input and output. Precision Cnc Machining,Cnc Machining Parts,Custom Cnc Machining,Precision Cnc Turning Parts Tianhui Machine Co.,Ltd , https://www.thcastings.com
The technological process
The technological process
In the production process, the process of changing the shape, size, position and nature of the production object, so that it becomes a finished product or semi-finished product is called the technological process. It is an essential part of the production process. Process: casting, forging, stamping, welding, machining, assembly processes, such as machinery manufacturing process generally refers to the part machining process and machine of the sum of the assembly process, other process is known as the auxiliary process, such as transportation, storage, power supply, equipment maintenance, etc. The technological process is composed of one or several sequential processes, and a process is composed of several working steps.
Working procedure is the basic unit of mechanical processing process. The so-called process refers to a (or a group of) workers, in a machine tool (or a working place), on the same workpiece (or at the same time to several workpiece) of the continuous completion of that part of the process. The main characteristic of a process is that it does not change the processing object, equipment and operator, and the content of the process is continuously completed.