Fab Academy Learning Resources#

Very Useful Video Tutorials#

(Check back often to see new videos that I will add as I find new good ones)

Documentation: Gitlab, Markdown & Atom#

Electronics:#

Eagle, KiCAD & PCB Production#

Fusion360:#

Arduino/Breadboard Prototyping:#

C programming AVR Microcontroller:#

Datasheet:#

Processing:#

CNC milling#

Eagle & PCB Design Tips and Tricks#

Eagle…appears intimidating. But in fact, Eagle is just a fancy vector-graphic, drawing program. At the end of your Eagle work-session, you will output 2 image files…one for the outline of your PCB and one for the copper traces of your PCB. If you think of Eagle as just a drawing program…then it is no so scary.

Theoretically, the 2 image files for your PCB can be made with ANY vector-graphics software, like Adobe Illustrator or Inkscape. What makes Eagle special…is that it includes extra features that makes the drawing of a good circuit board much…much easier.

  • Eagle has an expandable library of pre-drawn image files of electronic components to populate your PCB…this saves you time of having to draw each component with the exact dimensions on your own.
  • Eagle has a “Schematic” feature specific to electronics…where you to select all of the components you will need for your PCB, make the correct electronic connections between them, give them names and value lables, and check for electrical errors.
  • Eagle has a “Board Design” feature specific to electronics…that helps you to correctly layout your board by…reminding you of correct connections defined in the “Schematic” phase, choosing real-world based copper trace widths to make electrical connections, preventing traces to be drawn too close to one another (and cause milling or electrical problems later), etc.

What makes PCD design using Eagle difficult is not the Eagle software itself…but the electronics knowledge that is required to design a proper electronics circuit board. Because Eagle is just a drawing program, it can help but cannot completely help you to make a good functioning PCB. To be able to use Eagle comfortably to make a great Programmable Circuit Board (PCB), you will have to improve your knowledge of electronics and the microcontroller.

Some useful tips and tricks for using Eagle to make better PCBs on Eagle#

  • Make VCC and GND traces fatter than others. For electronics purpose, a fatter VCC line will mean a PCB that won’t generate as much heat. Thin traces means greater resistivity…more heat. For a visual purpose, making VCC and GND traces fatter will make these critically important traces easier to identify.
  • Use “Ground Planes”. Better than just having a fat GND line, use a “Ground Plane” or a big area of PCB copper connected to the ground pin whenever possible. Simply stated, a “Ground Plane” is beneficial to an electronics PCB because it reduces the resistivity of the path to ground and helps to reduce electromagnetic noise interference. A better, longer explanation of “Ground Plane” can be read here
  • Mark GND Pins. Many of the PCBs you will make will have either FTDI (serial communication), or ISP (programming) or Power (VCC & GND) Pins, combinations of them. In all these cases knowing the location of the GND pin will make correct FTDI, ISP or PWR connections much easier (and prevent the destruction of your PCB). It is recommended that some graphic (a letter “G” or just a dot”) be added to your board design next to your GND pin, to make it fast and easy to identify.
  • Keep Traces Short and Component Groups Close Together. For electronic efficiency, the shorter the distance between the Microcontroller and the component/component groups it is controlling the better. Long traces are “slower” and can create an “antennae” effect. When the board has component groups (ex: LED and resistor, Decoupling Capicitors), keep all the components as close to each other as possible.
  • Avoid 90 Degree Angles In Trace Lines. 90 degree angles risks being milled smaller than the trace itself…making it a fragile potential point of failure. Choose 45 degree or round trace bends instead.
  • Put the Resonator close to the XTAL pin of the Microcontroler.” The further away the resonator/crystal is from the MC…the poorer the timing function will become.
  • Every Microcontroller has a small mark in one corner (circle or triangle) to assist with pin identifications.” The pin locations for an MC must be correctly understood and oriented…to be certain that correct electronic connections can be made between the MC and other components.
  • In Eagle Schematic - Start with the Microcontroller (MC). Place the MC first and give practical, funtion names all the pinouts of the MC. For example, with the ATTINY45…instead of PB1, name the pinout MISO and instead of PB0, name it MOSI. And then for the 6-pin ISP header, also name the corresponding pins MISO and MOSI. Doing this will make trace connections in Board Design much easier.
  • In Eagle Schematic - Give Component A Practical Name. When you place an electronic component in Eagle, it will usually have a generic, coded, name…like “JS1”. Change such hard to understand names to something more practical…such as “ISP” or “RED LED” or “Light Sensor”. This will make Board Design and later on PCB soldering work easier.
  • In Eagle Board Design - Use the “Show” Command…to highlight specific electronic components. For example, “Show GND” will make Eagle highlight all the GND traces on the PCB…helping you to confirm that all ground pins and pads are connected.
  • In Eagle Board Design - Pay special attention to VCC and GND trace lines. A PCB will not function, if a “close-circuit” is not made. VCC and GND together create an electrical flow loop that cannot be broken in order to function. Most active electronic components (MC, sensors, LEDs, etc.) require power (from VCC) to operate, but also GND to allow electrical flow. All components on the PCB should connect to the same ground line (“Common Ground”).
  • In Eagle Board Design - Pay special attention to the polarity of some components. Some electronic components require correct polarity connections…one end connected to VCC and the other connected to GND…and the component will not function (or may be destroyed or damaged) if the polarity connections are incorrectly done. Take note of which components have polarity requirements and take special care to orient them and make connections to them on the PCB correctly.
  • Finally, Export 2 “Image” files”…monochrome, 800 dpi, called “(boardname) Outline.png” & “(boardname) traces.png”

Other Eagle tips directly from Autodesk here