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Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  Motor shield  is a platform for robotics and mechanical applications based on L298P. It can be used to drive double DC motor or a 4-wire stepper. When controlling double DC motor, there are Only 4 control pins are used, which makes more easily to control, and saves the control pins for controller. The Drive current can be up to 2A per motor output for the adding of the heat sink. Measure the driver current by the additional resistance, makes the system more smartly. 

RMF69 Shield-433MHz contains a FSK wireless module, it has the same function that radio frequency transmitter owns, such as receiving and transmitting message. RMF69 Shield-433MHz can totally compatible to Arduino. Features Low consumption More professional ISM band Frequent range from 140 to 960MHz  Totally compatible to Arduino http://juvtmall.com/rfm69-shiled_p0808.html

. PCB design considerations   Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  (1) avoid setting important signal lines on the edge of PCB, such as clock and reset signal. (2) the distance between the ground wire of the enclosure and the signal line is at least 4mm; keep the length and width of the ground wire to be less than 5:1 to reduce the inductance effect. (3) lock the device and line that identified location with LOCK function, so that they will not be misused. (4) the width of the conductor should not be less than 0.2mm (8mil). In high-density and high-precision printed circuit, the width and spacing of the wires are generally preferable to 12mil. (5) Routing in the IC pin of DIP package, 10-10 and 12-12 principles can be applied, as between the two pins by 2 lines, diameter of bonding pad  can be set to 50 mil, width and spacing of line is 10 mil, when o...

6. PCB design related concepts Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  Via  holes: Once selected, be sure to deal with the gap between it and the surrounding each entity especially easy to ignore the gap between the line not connected to via hole of each layer in the middle   and via hole, if it is a automatic wiring, can be in "number Via minimization" (Via Minimiz8tion) in the sub menu select "on" to automatically solve. The larger load flow required, the larger hole size required, such as the larger the hole in the power layer and the other layer. Silk screen layer: For the convenience of installation and maintenance of the circuit, etc., it need s   printing logo and  writing code   on the upper and lower surface of the printing circuit , such as component label and nominal value,   the profile  of   the component and th...

1.The design of PCB Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  In PCB design, the layout of the components and the wiring of the circuit are the two key links. Layout, means the circuit device in the printed circuit board wiring area. Whether the layout is reasonable not only affects the wiring work at the back, but also has an important effect on the performance of the whole circuit board. After guarantee ing  the circuit function and performance index, to satisfy the requirement of process, testing and maintenance aspects, components should be uniform, neat  and compact   on the PCB, as far as possible to reduce and shorten the lead and the connection between components, in order to get symmetrical   packing density . The position of each functional circuit unit is arranged according to the circuit process, the input and output signal, ...

5. see the version   Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  There are so many ways to see the version: 1.by smartphone First, download two software: JuiceSSH              this is terminal AndroidVNC           this is VNC used to display the version Ensure the smartphone and Raspberry Pi has connect to the same network, you can open the USB wifi share of smartphone, then connect Raspberry Pi and smartphone with an USB cable, try to get IP of Raspberry Pi. Open JuiceSSH, set a new connect, give it a name and input Raspberry Pi’s IP, connect it, you can see that it’s easy to write command via smartphone for it has serve for many shortcut key. Set up a software by the following command: sudo app-get install tightvncserver This command ...

4.Set static IP   Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  You may say: no, though I can use Wi-Fi and don’t need network cable, I still have to use Advanced IP Scanner to search IP of my Raspberry Pi, it’s so inconvenient. I will teach you how to set static IP First: input the following command: sudo nano /etc/dhcpcd.conf Secondly: input these command to the bottom line:              interface eth0 static ip_address=       (the static IP you want) static routers=          (your routers) static domain_name_servers=     (domain) Tip : this is the way to set eth’s static IP The following is about how to set wireless static IP: Input the command: interface wlan0 static ip_addres...

3.How to set the Wi-Fi?        Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  I don’t want to use a network cable every time I want to use my computer. There are two methods to connect computer to Raspberry Pi: First, you have to connect Raspberry Pi with a network cable. Method one : use the screen designed for Raspberry Pi, this way could be visible Connect screen to Raspberry Pi, 1.if you have download Raspbian from my link, just choose corresponding size below and input it into your XShell. cd LCD-show/                   This must be input sudo ./LCD35-show                   for 3.5 inch screen (it can also use for 4inch screen) sudo ./LCD5-show  ...