Electronics Design
This week the main task was to explore and make our own PCB design with Eagle PCB designing software. To learn and explore eagle we were given a task to design our own board with ATtiny 44 and few additions of other components to make our 'Hello echo Board' with addition of some other parts.
Eagle by Autodesk
Since this week was about designing the board, I focused more on how to use the features of Eagle more than how the board worked. So I just went with the schematic available from the site and tried things with Eagle.
Adding libraries
One of the most interesting thing is adding the components in the schematics, and there were tonnes of components in the eagle libraries to use so its could get confusing but luckily Fab lbr files for eagle was available. Fab Lbr had all the components that are in a FAB lab inventories so it was very useful for getting the required parts for the board i was designing. One of the cool thing is we can create our own custom libraries for the components we use frequently. This makes the job so much easy and faster.
I went to the fabacademy.org website to get to the libraries and how to add it. INSTRUCTIONS
After adding the lab using the instruction from above link, i check if the lbr was update by the 'add' command and it wasn't there at first so I went back to library on tool bar and clicked on update all and when i checked again, this time it worked.
Schematic(.sch)
Now its time for the real deal. There is two window that eagle enables to design the board. The schematic, which is the diagrammatic view of the board and the actual board we will manufacture. In schematic we just need to add the components we require and how they are connected to another components and they are all represented by symbols of the actual components. I found typing the command very much useful than click from the tool bar on the left side of the window.
closer view
Board(.bdr)
This is the window where we design the actual board. Here we can place the components accordingly as we desire, but also remember not to get the components too close for this will be hard for the machine to mill the traces and even if its done it will be hard to solder later. For this board i tried auto route but wasn't as I wanted it to be so I manually route the traces but i used the reference to traces that was on the fab academy tutorial and it was neat than the options on the auto route (specially for this board) . After checking the board design again and again after several time I made the png and started milling it but when the milling was done I found that I missed to add some traces so i did it again but this time I checked plenty of time before sending the files to mill.
Rendering the circuit
I tried rendering with the eagle to fusion 360 and I also tried rendering with 3Dbrdviewer.com . I found that 3Dbrdviewer.com had better quality of image.
outline
The tutorial given on the website was bit longer as I need to add a border from a image editor, I wanted to use some ways to make it from eagle it self so i drew a cut out line in the bottom layer of the board and I just selected the bottom layer in the view. I got an outline that i need so i saved a png of it to cut. But the modela read it as traces as the width of the line was too thick and it cut from either side of the outline i made.
The right way to get an outline from eagle
I tried using the bottom layers with different width size.
out line using bottom layer with 1 as width of the line
Commands I used
I used these commands more frequently and found them extremely productive for my work, most of these works in schematics windows as well as board windows. Some commands like net doesn't work in board windows but only works in schematic window.
1. add - this is for adding components in the schematic 2. move - this is for moving components, do remember you can only select a component only if the origin( a red plus symbol in schematic and a white plus sign in Board windows on the components) is visible. 3. net - this is to make a logical connection in schematic between components. 4. name - this is to add name to the components. 5. value - this is to add value to the components like 10k on resistors. 6. copy - this helps to copy components. 7. rotate - this helps to change the orientation of the component. 8. ERC - electronic rules check; this helps to check if your board will actually work 9. DRC -design rules check checks if there are error on the board, i had overlap issues but this doesn't cause any issues to the making of the board. 10.text - text adds texts into the board Since i am a beginner these commands were enough to get my jobs doneMilling
Now since all my designing were done I started with the milling the board. The first one was a fail as I accidentally missed to add some traces and i only realized after sending the file into the modela.
This is the second one, here I forgot to add a traces between the omiron switch pad 3 to 4 and 1 to 2. Inside of milling again I went with repairing it using wires.
<
Now its time for soldering the board
Since I forgot to add traces in my eagle design between the switch, I soldered a wire between the pad number 3 and 4 , and pad 1 and 2. Though I think its not required, I did soldered it.
I revisited the lecture and I found out that it was not required so I removed the wire back down. The functionality of the switch remains the same even with the traces connecting the pads on either side.
Group Assignments with oscilloscope
An oscilloscope is a laboratory instrument to test electronic which display and analyze the waveform of electronic signals. The device draws a graph of the instantaneous signal voltage as a function of time as it works. For this group assignments we explored the buttons and functions on the oscilloscope like the button of volts/div that refines the voltage in each division and also the sec/div which refines the seconds in each division. Auto run resets to default This is still a new instrument to me so I am exploring on-line tutorials but my focus this week was more on the Eagle software.