Eagle CAD Training

Written By: Muhannad Al Mohamed (E&C DM)


This blog is intended to introduce Eagle CAD designing application to members to be able to design schematics for electronic circuits. The members of the E&C division are required to know how to make schematics of customed printed circuit boards (PCB) for their corresponding projects. These schematics can be used to design the layout version of the PCB in the Eagle CAD layout part. The layout of the PCB can then be used to generate Gerber files; which can be sent to fabrication houses to make the PCBs.

Creating New Sketch

To start a new sketch a new project should be created and a name should be given to it. After that, a new schematic should be created within the project.

Creating a new schematic

Adding Parts

To add a part from the EagleCAD library, the add icon should be clicked where the list of all the parts would show in a window.

Add Icon

Parts can be chosen directly from the libraries by double-clicking on each part. The search window can be used to easily find a specific part. However, the EagleCAD search engine is literal; which means that any misspelling in the part name will not show any result. To avoid that, stars should be typed before and after the part’s name.

Placing parts

Placing a part is simple, one click should input parts into the schematic and by clicking escape twice it would quit the adding mode. To rotate parts, right click before placing any part. Rotation of a part or a group of parts can be obtained by clicking the rotate icons.

Rotating parts

Connecting Pins

To connect placed parts the net icon should be clicked. The edge of each pin should be clicked when connecting parts to ensure that you are connecting to the part not just drawing a line on it.

Net Icon

When connecting to a part make sure that a connecting window shows up asking for permission to connect to a part. When a connecting is done, double-clicking the crouser will quit the connecting mode.

Connecting Window

When connecting a line with a line, make sure that a junction shows at the intersection. If there is no junction showing, a junction can be added by clicking the junction icon.

Junction Icon

Unconnected lines

Connected lines

Labeling Pins and Parts

Parts can be given labels that can show names and values in both the schematic and PCB layout designs. To add a name label click on the name label and click on the desired part. A value label can be added to parts as well by clicking on the value label. Just a reminder, the value label is still just a name and does not have any relation to the part’s characteristics.

Name Icon

Value Icon

Pins can be named as well by giving them labels by clicking on the label icon and clicking on the desired pin.If a pin is named exactly with the same name to another pin, a window should pop up asking to connect the pins. If clicked true, the pins would be automatically connected without showing a line.  The labels appearance can be changed by clicking on the tag icon and the size of the label can be changed as well.

Label Icon

Regular and Tag Icons

Changing Size Icon

EagleCAD Libraries

EagleCAD has a lot of different libraries from various retailers and manufacturers. It also has the regular parts such as supplies, passive components, .. etc. However, sometimes the desired part is not found in the EagleCAD built-in library so in that case a new library should be added.

Adding Libraries

To add a library, its “.lbr” file should be downloaded first from the manufacturers’ website or from different websites that provide eagle libraries:

Once the “.lbr” file is downloaded it should be placed in the “lbr” folder in the application’s folders. After that, the library should be indicated as used in the library manager window.

Placing library in lbr Folder

Library Manager

Using a Library


Verify Connected Pins

If the pins were labeled with similar names, their connection can be checked by clicking the show icon. Once the show icon is clicked, by clicking on any pin it would show the connected pins the clicked pin in bold font. It is very helpful to trace pins and check if all the parts are connected correctly.

Show Icon

Connected Pins

Checking Errors

After creating the schematic, the design should be checked if it has any errors. By clicking on the ERC icon a window should pop up showing any electrical errors.  Make sure that you have no errors befor going to the PCD layout part of designing.

ERC Icon

Training Material

Schematic Training

Further trainings on creating EagleCAD schematics can be found here:

PCB Layout Training

Training on the making of the layout version of the custom PCB can be found in this blog written by Charles Banuelos (MFG DM).

Goliath Fall 2017 Verification and Test

Written by Nornubari Kanabolo MST DM

Verification and Testing

In order to verify and test the Goliath, the requirements needed to be updated. Updated requirements can be found in this blog post. Goliath testing is complete for the most part, but some tests still need to be done before 2pm on December 13th, 2017. The verification and tests that have been/will be done can be seen below in the following test cases from the Verification and Validation document.

Test Cases

TC-01: Goliath move forward

Description: The Goliath will use overwritten MOVE commands uploaded to the 3DoT board in order to move forward.

Test Environment: Occurs inside, on a flat surface with 0% grade

TC-02: Turn Direction

Description: Display turn direction on the LED array.

Test Environment: Inside a classroom

TC-03: Assembly and Disassembly

Description: Assemble and disassemble the Goliath within a specified amount of time.

Test Environment: Inside a classroom

TC-04: 3D printing

Description: Print 3D models in less than 6 hours, and no part takes longer than 2.

Test Environment: In room that has an accessible 3D printer

TC-05: Goliath dimensions

Description: Measure the dimensions of the newly designed and assembled Goliath.

Test Environment: Inside a classroom

TC-06: Arxterra Control Panel

Description: Control the newly designed and assembled Goliath using the Arxterra Control Panel.

Test Environment: Inside a classroom

TC-07: Charging Goliath

Description: Testing the ease of access of the charging port.

Test Environment: Inside a classroom

TC-08: Battery Life

Description: Running the Goliath motors continuously for 1 hour.

Test Environment: Inside a classroom

TC-09: Weighing Goliath

Description: Placing the fully assembled newly designed Goliath on a weighing scale.

Test Environment: Inside a classroom

TC-10: Measuring Goliath Voltage and Current

Description: Measuring the voltage of the sensor header and finding the current rating.

Test Environment: Inside a classroom

TC-11: Detecting objects

Description: Detecting objects within a specified range.

Test Environment: Inside a classroom

Rules Of The Maze (Robot Avoidance Rules and Strategy)- Part 2

Written by Nornubari Kanabolo MST DM

Special Case 2.3(T-intersection) continued

As Matt explained in the previous post, for 2 robots at a T-intersection:

“In this case the robot that is within the intersection (in the middle of the T – intersection) has the lowest priority and must move out of the way of the other robots (if the other robots are in the path of the low priority robot). The lowest priority robot will step down the hallway that is not blocked and then wait for the other robot to pass.”

As for the case with 3 robots at the intersection, the following method could be used:

Say R2 steps into the intersection and R1 needs to go where R2 is and R2 needs to go where R3 is. One thing that could happen is R3 goes back to the last intersection to wait and R2 waits 5 seconds to move one square to the right.

At this point, 2 possible cases could happen. Case 1 as follows:

R1 waits 5 seconds and sees that there is no one in the intersection now then moves into the intersection, so that it can go to the hallway where R2 was. R2 waits another 7 seconds and goes down to where R1 was. R3 waits 3 seconds and returns back to where it originally was.

Or if R2 needs to go where R3 is then Case 2 is enacted as follows:

Since there are no longer 3 robots at the intersection and it is now just 2 at an intersection, the rules for encounters 2.3 as stated by Matt are used.