07. Electronics design
This week’s assignment was to redraw the echo hello-world board using Eagle and then fabricate it.
you can find the my folder here to download
from my background of architecture i needed to review the electronics from scratch
. and here is some of my noted i take during our electronics revision 8
three main things i need to consider while designing electronics :
- add components to the schematic view and then create correct connections between them.
- check and verify the design using the ERC (Electrical Rules Check).
- finishing the connection of components and fix any rapid errors -switch to board view and place the components and route the traces.
three main components meanings:
CURRENT is the directed flow of charge through a conductor. VOLTAGE is the force that generates the current. RESISTANCE is an opposition to current that is provided by a material, component, or circuit.
it was a bit scary to open eagle at this time but here we go 8
and here are the two main windows we are going to use to build up the board.
Schematic (.sch) - logical components Board Layout (.brd) for the actual board that we mill
and we can switch between them using this button
as directed by the tutorial i needed to download the fab library of examples. so i downloaded it from this and copied paste it the folder inside the library folder inside the program. what’s next is to open a new project by right click on projects and then open the schematic view 8
to use library i added i will go to library and library manager and then browse from the library location on Eagle program files
this is the board that i will redesign so starting with
and then we need to start adding component accordingly to the board.
- add button
- add grounds
- add VCC
- add LED
- add resistor
there is an important note to consider: knowing the function of the board is an essential part of designing electronics boards after that we can look at the data sheet for the microcontroller.
Datasheet for my microcontroller i found it here: http://ww1.microchip.com/downloads/en/devicedoc/Atmel-7701_Automotive-Microcontrollers-ATtiny24-44-84_Datasheet.pdf
Datasheet includes very useful information about architecture of this device. The most useful information for current step is pins configurations:
after adding the components i wanted to add VCC and GND .
As per the original echo hello-world ATtiny44 board and using “Net” tool, add wiring to components. wan to make sure to draw direct connections between components when it’s possible!
Switching to the pcb designs :
Fine yellow wirings represent the connections made in the schematic. All those wirings should be replaced using “Route Airwire” tool. from this as (fabcity-designrules.dru) copy paste to “..\Documents\EAGLE\design rules”.
In Board Editor go to “Tools > DRC…” and then select “File” tab. Click on “Load” and locate fabcity-designrules.dru on your drive. Click “Open” and then “Apply”. The DRC window title is changes to DRC (fabcity-designrules). Click “Select” to close the DRC window.