Week_6 - Electronics design

Assigment

  • group assignment:
    • use the test equipment in your lab to observe the operation of a microcontroller circuit board
  • individual assignment:
    • redraw an echo hello-world board
    • add (at least) a button and LED (with current-limiting resistor)
    • check the design rules, make it, and test it
    • extra credit: simulate its operation


Group Assignment

use the test equipment in your lab to observe the operation of a microcontroller circuit board

Use the test equipment in your lab to observe the operation of a microcontroller circuit board (in minimum, check operating voltage on the board with multimeter or voltmeter and use oscilloscope to check noise of operating voltage and interpret a data signal) Equipment used in testings:

Multimetr

"A multimeter or a multitester, also known as a VOM (volt-ohm-milliammeter), is an electronic measuring instrument that combines several measurement functions in one unit. A typical multimeter can measure voltage, current, and resistance. Analog multimeters use a microammeter with a moving pointer to display readings."

Wikipedia


The best way to start working with a multimeter is first of all to read the manual, which is always available with multimeters in our lab.


Oscilloscope


An oscilloscope is a laboratory instrument commonly used to display and analyze the waveform of electronic signals. In effect, the device draws a graph of the instantaneous signal voltage as a function of time.
we have in our fablab :

Rigol DS1054

  • Fifty MHz band, 4 channels
  • Sampling rate 1 GSa/s
  • Aquisition memory 12 Mpkt (Standard) optional up to 24 Mpkt
  • Fresh rate up to 30 000 passes per second
  • Frame recording option: up to 60,000 frames
  • Low noise, gain from 1 mV/dz to 10 V/dz
  • Optional triggering and decoding of serial buses (RS232,I2C,SPI)
  • Multit-level gradation of the brightness of the waveform display
  • Full set of interfaces: LAN (LXI Core Device 2011)，USB Host & Device,
  • AUX,USB-GPIB(Option.)
  • Display 7-inch WVGA resolution (800x480)
  • Dimensions (Width × Height × Depth): 313.1 mm × 160.8 mm × 122.4 mm

    link to manual
    link to software manual

    Laboratory Power Supply

    The power supply first uses a rectifier to convert house alternating current (AC) into direct current (DC), the only type that common instruments and devices use. It then adjusts the current and/or voltage upward or downward to meet the needs of the instrument.

    Using equipment
    Multimeter
    The most common task for the multimeter during our work with pcb boards so far was to use it to check the continuity of the circuit and ( buzzer) and check the solders/resistance. It is also very important to check if we have connected FTDI pins to Attina microcontroller.


    Power supply
    Power supplier is the best tool to give precise power to the machine and to test what changes will be brought about by increasing or decreasing the current and voltage. All changes are made using two knobs, one for voltage and one for current. It is a very simple tool which allows us to quickly test and check how our board works under different current conditions. For Tiny boards the voltage is 5v. The board can be powered by FTDI by connecting it to the appropriate pins ( previously it can be checked with a multimeter).
    After connecting 5v, you will see how much current the board is consuming. This is very important information to determine the battery life of the device.

    individual assignment:

    Redraw an echo hello-world board

    For the first time in my life I designed pcb boards so I had to learn the program and the elements of the electronic circuit. To learn the program I used a very good and simple tutorial available on Fab Academy website. To remind the basics of electronics I used instructables Electronic classes . Eagel turned out to be a very logical and easy to use program, it was enough to logically separate schematics and boards and learn basic commands.

  • add = opens up the libraries so that you can add components in Schematic view
  • move = moves and rotate (using right mouse button) an item
  • net = makes a logical connection
  • junction = adds a junction
  • value = addes value to components (i.e. ohm rating)
  • name = names a component
  • label = displays the name of a component in schematic view
  • copy = copies an existing component on the schematic.
  • route = used in Layout view, this tells you if you need to add a connection (follow yellow lines)
  • ERC = electronic rules check; this ensures your board will actually work (use in schematic view)
  • DRC = design rules check (in board view) - keep all the default settings (16 mil is fine); it should display a "no error" message in the bottom left hand corner of the screen
  • group = groups components in Layout view together; if you right-click, then you can choose Move: Group to move the grouping
  • rats = in board view, tells you if you have airwires
  • rip = deletes connections in layout
  • show = after typing this, select a component to see information about it displayed in the bottom left corner of the screen. Also, if you type show + [name of component] you can see that component highlighted. You can use this to see all the ground traces, for example.
  • text = allows you to add text to your board. You can also edit the exported .png file in The Gimp to give text and black and white line images. I recommend adding text in The Gimp.)
  • info = then click on text to get properties of the text

    Schematic

    and it's always good to know where are the buttons in ui of the software. We always start by creating a design and a schematic of the board.


    eagle UI

    You always have to check if we have an imported library of plots in our libraries, which can be downloaded from here)
    After adding the library we search and add all necessary elements to the layout. We combine all the parts by giving the net names.



    after i created the schamet its time to switch our view to board with the button on the top left (shown on previous screen)

    Board

    Routing


    Routing


    DRC check


    using presets to export routes and pads only


    File=>Export=>Image


    After exporting routes and pads I creat the new layer with border of the board. I creat the new lines on layer dimension (because i didnt use this layer into the design)


    Creating the borders of the PCB using lines


    Using Fab Moduls i creat the path for a cnc machine


    Prepered files into the cnc software

    soldering and final board

    all files from projects