Presently, Eagle is included among the different programs for PCB layout, which you can acquire at no cost. Other programs similar to this are DipTrace and KiCad. This Eagle free version is limited with respect to what it can achieve or do. The DipTrace is slightly more. On the other hand, KiCad is an open-source program, and therefore it is totally free.
For me, I prefer Eagle due to its reasonable limitations or what it is intended for. Also, I prefer its interface in contrast to that of KiCad.
Now, if this is your first time installing Eagle, it is possible that you’ll want to make use of the licensing option ‘Run as Freeware’ anytime it pops up. Take note that before using this instruct able, you have installed at least the Eagle 6.1 or a higher version. The files you are uploading or web page load may be stored in the xml format of Eagle 6 and therefore you will not be able to open it using Eagle’s earlier versions.
Before we go into full details regarding Eagle software, let’s first move around a completed project.
Steps in Printed Circuit Board (PCB) Creation Using Eagle
How Does Eagle Work?
The UI of Eagle is designed using a modal interface. What this means is, you choose a mode, then perform it a number of times, in contrast to choosing an object as well as applying one operation at once. If it is utilized properly, you will be able to work very quickly. It can also collect behavioral data, However, this could also be an important source of possible aggravation; that’s if you usually make use o the Windows-y method of achieving things.
There are four main views in Eagle. These include the Schematic, Library, Control Panel, and Board.
- For the Schematic Window, it is where you’ll draw your project’s schematic. It helps in defining the different parts present in the project. This pins on those parts you should connect.
- The Library allows users to manage as well as edit parts.
- The Control Panel serves as the major window. With the control panel, it launches every other thing and whenever you close the control panel, all other subordinate windows are closed.
- The Board is where all the pieces and parts of the project re laid out and it also connects the right pins physically, the way the Schematic defines it.
Take note that the Job of the Schematic is to define all the part as well as the connections found between them. It is only in the board layout is it necessary where all the parts will physically end up.
Also, on the Schematics, all the parts will be laid out in areas where they will function electrically. When they are laid out on boards, it will be in areas where they make sense physically. Therefore, a resistor placed right next to any specific part of the Schematic might appear far away as possible from that part in the Board.
The Control Panel
This is Eagle’s main window. Immediately it is closed, it will also close all the windows you have opened earlier.
Below is a brief description of the different categories present in Eagle’s control panel.
- Libraries or .lbr files helps in storing all the parts onto the board
- The design rules is what the idiot-checker or design rule checker makes use of
- User Language programs, which is denoted as .ulp, makes use of the User Language of Eagle in achieving stuff that would have been difficult, impossible, or tedious without them
- Scripts, denoted as .scr are some eagle command. Furthermore, they are less powerful and simpler than the ulps.
- For CAM jobs, denoted by .cam, they help in exporting to the other formats
- Projects like .pcb, .sch, are areas where the schematics, printed circuit boards, and all other things live
Therefore to begin, right click ‘eagle’ and then choose ‘New Project.’ You can refer to it as ex-Compass.
Next, go ahead and download the ‘Compass.pcb’ and ‘Compass.sch’ files, then save them in this location: Documents\eagle\ex-Compass
Furthermore, tap F5 or search for View-Refresh present in its Control Panel. This makes all the necessary files appear in there.
Next, double-click the Compass.sch file. Both the printed circuit board file (PCB file) and schematic should load.
The Schematic Window
This is the window whereby you can create as well as edit your schematic. To begin, try to move around. There are three different ways n Eagle through which you can move around. You can either use the mouse, the keyboard having the F# keys, or the scroll bars. The latter is only for those who don’t have the first two.
Make use of a mouse having a middle button. You can middle click and then drag and move around, zoom out and in, and scroll down and up. Furthermore, when making use of the F# keys, the F4 is for zoom out, the F3 key is for zooming in, while the F5 key helps in centering the screen whereby the mouse can be found.
For the dragging of the bars, do that on the sides and bottom of your screen making use of the top button. Also, you will find the sheets area at the right hand side of all the buttons. With the complex schematics, as well as Eagle’s non-freeware versions, users will be able to create the multi-paged schematics and most appropriate web page, then switch in-between them here.
However, if you are working with the free version, then you may close it and then forget about it. After looking at this schematic for a short while, then you can realize the schematic can be laid out in a better way, most especially near the voltage regulator.
The Board Window
You can move around the board window the same way you do the schematic window. So also, their show button is somehow identical as well. The board window and the schematic window also have the same function for the display button. The only difference is that the broad window view features different layers
In isolating the topmost layer, tap the Layers button, and then select None. Next choose these layers:
Pads, Top, unrouted, vias, tPlace, Dimension, tNames, tPlace, tOrigins, tValues, tNames, _tsilk, tDocu, tKeepout. tValues is optional, same for tKeepout, but this has to do with the situation. tDocu is optional as well and adds some more clutter.
In isolating the bottom layer, all you need to do is click the button of the layers. Next, click on None and then choose these layers. These include:
To isolate the bottom layer, click the Layers button, then click None, then select the following layers: Bottom, Vias, Pads, Dimension, Unrouted, bPlace, bNames, bOrigins, bValues, bDocu, bKeepout, and bsilk. tValues is optional, same for tKeepout, but this has to do with the situation. tDocu is optional as well and adds some more clutter.
In order to view the two layers, just enable all the options above. This could be a very tedious affair when you are swapping very quickly between the sides.
Now you have seen and understood the basics of the Eagle application, now let’s go ahead to create a circuit board.
Important Definitions to Help You Understand Better
Part: This is referred to as the physical components of a printed circuit board (PCB), which are contained and placed in a library.
Net: This is an electrical connection found in the schematic view
Trace – This is similar to a wire present on the printed circuit board (PCB). This is the Board View. The Trace is useful in making the definition of the connections by Nets.
Plane is usually linked to the ground. There are cases whereby you connect it otherwise, most times for the situations requiring high-current-carrying ability. Furthermore, with this plane, you will define a border, then the plane will be able to fill enough area in that border. This leaves enough room for the traces present inside.
Wire: In the Board or Schematic view, this will not be shared in-between them. These are usually used for only cosmetics in the Schematic view. For the Board view, it is used for plane or cosmetics modifications. Note that you must not use this in drawing electrical connections! Please avoid this.
Label: This reveals a net’s Name.
Value: This is a value of a specific part. All you need is having either a specific part number to serve parts that are more complex, or the real and actual value to serve simple parts such as capacitors and resistors.
Name: This is a special identifier for every part
Creating a New Schematic and Project
For the purpose of this tutorial, we will be creating a circuit, which blink the LED making use of the 555 timer chip. This timer is known as a simple chip, which has different uses. Also, we will run it in the stable mode that creates a square wave.
Below are the steps used in creating a new schematic and project.
- Create your new project by going through this process: click file, then new, then project
- Next, is giving the project a very descriptive name, for example ex-555-Blinker
- Next, right click the project, and then click on New, and then Schematic
- Then, name the schematic, for example ex-555-Blinker.sch
Adding the Parts to Your Schematic
To add the parts to your schematic, just click the Add button. You can also type Add, then type *555 in your search box. It is obvious that we will wish to have the one present in the st-microelectronics library. Making use of the process, add the remaining parts:
- R3, R2, and R1 – which is gotten from Eagle’s resistor library
- LED1 – ‘CHIPLED_0805’ part gotten from ‘LED’ library
- G1 – the ‘AB9V’ part is gotten from ‘battery’ library
Connecting the Parts
Once you have gotten all the parts properly laid out, then it is high time for you to connect these parts.
You can connect them by making use of the ‘net’ command. When making connections of this nature, don’t make use of the ‘wire’ command. ‘Wires’ are just cosmetic in Eagle’s Schematic portion, therefore they will not do whatever you desire. However, if you wish to utilize the Wire command, then get ready to break your heart.
Here are some important notes you should take note of when using the ‘net’ command.
- It begins with just one click. You don’t need to double click or click-and-drag to begin.
- You can start it anywhere
- Once you have started, the net will continue to be drawn till you click once on another net or pin, or by double clicking anywhere.
- Clicking once after you start, will ensure the anchoring of the net in the present spot
- When you right click, it will alter the way at which the net moves from the point A to the point B.
Labeling and Naming of the Nets
By making use of the ‘Label’ command, you will click on each net. This is to ensure that the names of the nets are shown on the wires. Immediately the names are being shown, give your wires some meaningful names by making use of ‘Name Command
There are two main reasons why you need to label the nets:
- Anyone can have an idea of the function of each portion just by looking at your schematic
- Secondly when switched to the routing of your board, it becomes very easy for you to tell the function of each net and then plan accordingly.
Assign Values to the Parts
Using a ‘Value’ (which is next to the command – ‘Name’), then go ahead to label the capacitor and resistors with the right or appropriate value
Furthermore, R3 is known as LED’s current-limiting resistor. Also, R2, R1, C1 helps in determining the rate of the LED’s blinkiness.
Electrical Rule Check
By running the ERC, you will be able to see those areas whereby the Eagle software eels you have not done well. Now, let us consider the output for this.
For Errors (1), these require that you take a careful look at it. Any mistakes here could lead to a blow up of your circuit once you don’t pay special attention.
Furthermore, when you see something like Unconnected INPUT IC1 CON, this means that your unconnected input pins have become bad. For cases like this, your CON pin serves as a reference voltage which you will be able to set manually.
The Board Layout
It is easy to create the PCB layout base from your schematic. All you need to do is visit File, then Switch to board. If it notifies you that the board does not exist, select ‘Yes’. This will help in creating the board from your schematic.
As soon as the board file pops up, you will see a box appear on your screen, having the parts to its left side. Till you decide to move it, it represents that area whereby your parts can be placed in Eagle’s free version. If you make efforts to move one part outside the area, Eagle will scream at you and will not respond or cooperate.
Getting the Right Side
There’ one thing with PCBs (printed circuit boards), which is their two sides. Moreover, you pay for every layer used, and if you’re making the board in your home, you may only make just one-sided boards reliably. As a result of the logistics involved in the soldering of the through-hole parts, it means that the PCB‘s bottom is what we will want to make use of.
Make use of the mirror command and then click the surface mount parts that switches them onto the bottom layer. The3re may be a need to make use of the Move or Rotate command. This is to help in correcting the parts’ orientation.
Normally, one friend of yours is the ground plane. Also, they ensure that all the tutorial’s remaining steps come easier. Also, they cut back with respect to the time that has been spent on etching if you decide to make this board from the comfort of your home.
The ground plane usually takes all the space left unused on the board and then connects it onto its ground net. After creating the plane and then run the ratsnest, you will experience that the airwires left out will drop dramatically. Furthermore, for Eagle, to make your ground plane, go ahead and run your Polygon command.
Routing the parts
Making use of the Route command, search for any airwire and then click on it. You should find a blue trace on the airwire’ node which is close to that area that you have clicked. If what you get is a red trace, then it isn’t what we wish for. Go to the top and then change its layer from red, which denotes the top to blue, which denotes bottom
Next, click somewhere else again to help in anchoring the wire at this point. Next, right click this to change the turn’s angle and then click at the middle to help in creating a via in-between the bottom and the top layer.
Revisiting the Orphans and Thermals
In this stage, three screencaps exists. The first screencaps of the printed circuit board with the thermals excluding orphans. Furthermore, the second screencaps are the orphans and thermals. Lastly, the third screen caps are the orphans, exempting the thermals.
Design Rule Check
For design rule check, it helps in checking the board that you have designed with some rules. This helps in determining if there are any errors. Though it is not perfect, it will locate or find a lot of mistakes and errors. Let’s quickly describes some of the important tabs
- File – This allows users to choose whatever DRC file they wish to make use of. Both Facebook data, both LinkedIn data, both adwords data, both doubleclick data, both onesignal data, both quantcast data and both twitter data. Some cookies collect data too. Some services such as OSH Park have one that you can download.
- Clearance – This indicates to the Eagle software the amount of room that you wish to have in-between these electrical contacts present on the circuit board
- Layers – You cannot play with this because we will be making use of Eagle’s freeware version. However, if you have a license (a paid one), then you can add layers by changing the set up to form something such as (1*2*15*16)
- Distance – The Dimension/Copper has to do with the distance found from the routing to the circuit board’s edge. The Hole/Drill has to do with the distance from the routing to any hole present in the circuit board.
The DRC Results
There are two options for you if you wish to fix the trace width:
- Right-click on Trace, then click on properties, then go ahead to adjust your width
- Next, is click on “change”, click width and then choose your new desired width
Another option you can make use of is to type ‘Change width .032’. Note that you can use whatever value you wish to work with. Working with this Change tool is a strong one. Just take your time to learn it and you will have great improvements in your experience with using Eagle
One Final Thing
Some people have discovered that an LED, which is found on a PCB’s bottom side, will be hard to see when you mount flush the PCB against a particular thing. Let’s avoid making this error again.
- Make use of the Ripup command, if you wish to get rid of the traces that lead up to your LED.
- Use the Mirror command, if you need to move your LED onto the topmost layer.
- Use the Route command, to route a particular trace present on your bottom layer around halfway to your LED for every airwire
You are done
Immediately you are through with the routing and there are no DRC errors present again, then you have completed this tutorial.
Hope you have a full understanding of what the Eagle PCB design software is all about. Just follow the tutorial over and over again to have a full understanding of the topic. This software can be used to collect behavioral data, advanced analytics processing, as well as other great benefits