Contextual Electronics Blog

Drill Tables and Fab Notes on a PCB Fab Drawing

Chris Gammell — Wed, 24 Mar 2021 12:45:21 GMT

Summary

In the video below, we're adding more information to our fabrication drawing for our PCB, including a drill table and fab notes. This allows us to get a board quoted or manufactured by a wider range of PCB houses than the online options. The online fab services capture all of this information in an online form dialog, like the one shown at the bottom of this post. Instead, we will add the required information to our fab drawing. With a fab drawing, we have a record of what we want the PCB to look like and what the critical specifications are.

Watch the associated video

This post is associated with a video on YouTube. Watch it below or over on YouTube.com.

Adding a drill table to your fab drawing

We use KiCad for all Contextual Electronics projects. If you use a different layout tool, you will need to figure out how to generate and add a drill table. The idea is the same for all designs though: we want to indicate how many different size drills are used on the PCB shown, and how many drill operations are required. This will impact the cost of the PCB because more drills means more time spent on the machines that do the drilling. See this time-tagged link to Scotty's video tour of JLC (Strange Parts) to see how drilling is done. KiCad has a tool buried in the "generate drill file" dialog. Normally this dialog is used to generate a .drl file, which gives all details about the location of drills and is used to actually program the machine that does the drilling. There is also a "generate map" button in the lower right, which will generate a vector based image showing where all of the various drill types are located on a particular PCB. After we generated this

Adding fab notes to your fab drawing

Fab notes are there to tell your manufacturer the detailed build information for creating your PCB. In an era before online tools (screenshot example below), this was the only way to get information across in a standardized manner. Many PCB fabs without an online interface requires fab drawings to ensure they are making a PCB that the engineer and company requesting the board actually wants. This includes details like the soldermask color, the silkscreen color, the overall board thickness, inspection requirements (IPC), or any other requests you have. We recently were pointed at this article from Supplyframe Hardware about some standardized notes you can add to your drawing. This is not an exhaustive list, but it includes a good "starting point" for people that are new to building out their fab drawings for working with traditional PCB fabs. It's also possible to include the fab drawing with your designs going to online PCB houses, to ensure they are hitting your requirements. Be sure to call out the fab drawing (and remember to upload it) when you are submitting your design.

Previous video about fab drawings

In the previous video about fab drawings (below), we discussed the stackup and how to create your own. We also linked to our library of templates for adding to your drawings.

Learn more about the ABC board

The ABC board shown in this video is part of a many part series (100+ videos) showing the entire design, board bringup, and firmware design of a cellular and bluetooth device. New members can try a week of Contextual Electronics for free.

Example PCB Fab Drawing

[caption id="attachment_11981" align="alignnone" width="1024"] Example PCB Fab Drawing (The Contextual Electronics ABC board)[/caption] Click the image above for a PDF version of the fab drawing

Example online selection tool

This is a screenshot of a popular online PCB provider (JLC). Interfaces such as these allow for a standardized quoting process and fast-forwards board ordering, compared to how PCB orders traditionally are done. However, with these interfaces you have less overall control. You are basically ordering from a standard offering.

Add mounting holes to a layout, but not the BOM (KiCad 5.1)

Chris Gammell — Wed, 17 Mar 2021 09:55:17 GMT

This video was inspired by a question on Twitter a couple days ago: How do you add a mounting hole to a design, but not have to worry about it when you get to production?

Add custom fields (Like "Population") to indicate it's a Do Not Populate (DNP) component
Mark all manufacturing fields as N/A
Use the KiBOM plugin to generate your BOM, which uses Regular Expressions (Regex) to exclude mounting holes, test points, solder bridges and other non-component components from the BOM

This is only a problem when you add your mounting hole to the schematic, so that it has a symbol that can be paired with the footprint. If using the footprint in a standalone manner on the layout, be sure to "lock" your footprint.

Joulescope Unboxing and Teardown

Chris Gammell — Wed, 10 Mar 2021 08:57:50 GMT

In a first for this channel, Chris does an unboxing video (and brief teardown) of the Joulescope. Matt Liberty, creator of the Joulescope, sent a replacement unit to Chris after a unit issue. This unit will be used to measure current on the ABC Board in upcoming videos. Chris hopes to measure how long the ABC board will be able to survive in the field without charging via a solar panel. The Joulescope is a high dynamic range measurement device, which is good at quickly switching between measuring the low current of a sleep state on microcontroller and then measuring the much higher current draw of a transmit cycle on something like a wifi or cellular modem.

Apply to be part of the Beta Consulting Course

Chris Gammell — Wed, 10 Feb 2021 09:36:09 GMT

TL;DR: We are offering a new course on Contextual Electronics about how to "go pro" as a technical design consultant. Apply below to be part of the early access program.

How To Create Electronics For A Living

There are a few different paths towards creating electronics for a living:

Get recruited by a company out of a university
Get hired into a company as a technician and work your way up to creating electronics
Design your own electronics to create and sell
Work as a contractor or consultant and design electronics to a customer's specification

Many people join Contextual Electronics wanting to learn how to build electronics. They want to build devices for personal enjoyment or to solve a problem they have in their life. For instance, one of our members built a monitoring system for a friend's farm, testing whether the fences were operational. The member was able to learn the underlying technology and enjoyed doing that, while also helping his friend create a valuable device for their business.

Technical knowledge has value

As the above example shows, CE members create things that have very real value in the world. Some members decide to manufacture products and sell them to others. But what about members who don't want to take on manufacturing or sales piece of creating a product? It's possible to offer design services for money. This is a very natural conclusion for people looking to build hardware full time. As Chris explains in the video below, there are many other considerations when getting started as a technical consultant.

Video Introduction

Why "Technical Consulting"? Why not just electronics?

This course is broader than just electronics, because the knowledge is for anyone looking to build a technical consultant business. This might include software, mechnical, civil engineers.

Apply to be part of the Beta Consulting Course

We are seeking early members of the "Hang Your Technical Shingle Course". They will give feedback on the existing and future content and be part of a group working together to build out their technical consultant businesses. If you are interested in taking part, please fill out the survey below If you cannot see the embedded form below, please follow this link to fill out the form: https://forms.gle/9WEPKQJUiFG3CSLTA Loading…

Other thoughts?

Please click the link to the associated forum post below to discuss more with Chris and other members of the community.

Importing Eagle files into KiCad 5.1

Chris Gammell — Wed, 27 Jan 2021 09:53:44 GMT

In this video, Chris imports the adafruit Feather M4 Express board Eagle files (which is OSHW) into KiCad 5.1. Here are some of the pitfalls of importing into KiCad.

Flags get converted into (tiny!) labels that might not be clear.
The frame in schematics is gone. Not a big deal, but will look different than other KiCad projects.
Some silkscreen layers will not map as expected.
All footprints are imported from Eagle, since KiCad doesn't know how to map existing footprints. This means that none of the 3D models are included.

KiCon 2019

Chris Gammell — Fri, 04 Jan 2019 04:32:35 GMT

An interesting event for electronics developers and enthusiasts!

This is a list for people interested in electronics. More specifically, you signed up because you were interested in Contextual Electronics (CE), the online electronics apprenticeship program. Today I'm writing to you about an event that Contextual Electronics is sponsoring and helping to organize. We think it is very relevant to people on this list and anyone interested in designing electronics with open source tools.

KiCon 2019

KiCon 2019 is the first ever user focused KiCad conference and is happening April 26th and 27th 2019 in Chicago IL As you may know, KiCad is a very big part of CE. We use it in every design we showcase on the CE site. We're hoping that some of you will decide to take your learnings and share them at KiCon 2019. We're looking for speakers to give talks about how they are using KiCad in their jobs, businesses and schooling. Or just how you use it for fun! Please apply to give a talk here! There are no requirements on how advanced you are as a user, so talks could be something like, "My perspective on getting started in KiCad". Please also consider attending! We'll also have the opportunity to give feedback to developers and help brainstorm what else is needed for KiCad. Not only that, but we'll be able to interact with other KiCad users and share tips and tricks. We're also planning a layout contest and other fun interactive activities. Not able to make it? Please help spread the word about KiCon! (Example tweet here, though any promotion is appreciated) In return, we promise to record and share the talks from the conference so you can view them later. And finally, if your company has the means, please consider supporting KiCon as a sponsor. Watch the announcement video here:

Future KiCad videos

We are revamping KiCad videos right now! KiCad version 5 came out a few months ago and has been another great improvement to the software. We have been updating all tutorials and how-to videos for KiCad 5, but have been waiting for stability and UI changes to calm down on development. We believe we have reached that point. If there are any videos you'd like to see, please let us know on this CE forum thread.

2019 and beyond

We're really excied about KiCon 2019 and really 2019 in general. Happy New Year and hope to see you all on the CE forums soon!

Should you switch to KiCad 5.0?

Chris Gammell — Fri, 02 Mar 2018 06:13:30 GMT

TL;DR: The KiCad 5.0 package is not yet at a stable status, as of March 1st, 2018. Wait until the official 5.0 stable is announced to switch.

Should you consider moving to version 5.0, since the new release candidates (rc1) are now being tested? I don't think so, yet. Watch below to learn more.

Links from the video

Using the Digikey Open Parts Library components

Chris Gammell — Wed, 28 Feb 2018 04:04:58 GMT

TL;DR: Digikey created a library for open parts library components and we made a video (below) showcasing how to pull that into your design One of the exciting thing in open source projects is the beginnings of broader adoption. Not only is it rewarding for the project members who have put in hard work on a software project they believe in; for the users of the project, it means there will be broadening support from the community. We hadn't announced it on here, but Digikey started supporting the KiCad project. This was both a monetary donation (announced at FOSDEM) and also in terms of internal support. What that means for users is there are now component libraries pre-built for components listed on the Open (Common) Parts Library. The "atomic" part refers to the fact that the schematic symbol and footprint are tied together. If you select the symbol for your schematic, no updating is required when you import components from your netlist into your layout. There are reasons for and against doing it this way, both of which I discuss in this video. Watch to see how you can add the library to your next project:

Also, as mentioned in the video, we started selling KiCad apparel and all proceed will benefit the software development process. Read more about the donation here, if interested.

Should you buy high end test equipment?

Chris Gammell — Sat, 26 Aug 2017 22:07:05 GMT

New members of Contextual Electronics and people learning electronics often ask me if they should be buying expensive test gear. I don't think so. Instead, I think you should focus on getting started with lower end equipment and using it to its limits before deciding to upgrade to high resolution or speed models. The important thing is to focus on the methods of measurement and troubleshooting, not getting bogged down with the specs of the gear you're using. Two of the devices we use for the course that were discussed in the video above:

Those links go to the "skills" modules, showing overviews of how to use the devices. We also use them regularly in course content. If you're reading this and not yet a member of Contextual Electronics, we also offer a discount on the Analog Discovery 2, so new members can get it at the "academic" discount when signing up for 3 months of Contextual Electronics. If you have questions about the above video or the AD2 bundle deal, please ask in the forum below.

Analog Discovery 2 Bundle Announcement

Chris Gammell — Wed, 09 Aug 2017 16:47:35 GMT

I’m excited to announce today that we are working with Digilent to offer a bundle deal that grants new members access to the Contextual Electronics (CE) course materials and student pricing on their popular Analog Discovery 2 (AD2) tool! This is the first time that educational pricing has been offered outside of a university setting and I'm so glad they decided to offer this to us! When you make a 3 month commitment to Contextual Electronics, you can buy the AD2 Contextual Electronics Bundle at a reduced price; the bundle also includes a BNC breakout board and probes that plug into those BNC connections. There are two options for future CE members:

I’m quite excited about this offering for a few reasons:

Instant signal visibility

In the world of electronics, nothing is really “visible” to the naked eye. Without visualizing what is going on in a circuit, it can be very difficult to troubleshoot circuits they build. Since CE members are normally beginners, their setup is less equipped than people working in the hobby or industry for a while. Circuits are unlikely to work on the first try and this tool will help diagnose issues.

A range of tool availability

How did CE work without test equipment? Well, we didn’t. We have a standard list of low cost equipment, including DMMs, power supplies and soldering equipment. But the key missing piece has always been the oscilloscope. The entry level scopes are $400 and above (though these costs continue to drop); add up necessary test equipement, components on hand and having a range of hand tools for building boards and the startup costs can reach past $500 (even without a scope). With the Analog Discovery 2, we not only get 2 channels of oscilloscopes, but also 2 signal generators, logic analyzer capabilities (including protocol analysis), power supplies, DMMs and more. See the full specifications here.

Portability

Notice I didn’t say a bench tool when talking about the AD2. It's possible to take this device with you on the road or to your next troubleshooting spot. Anyone who travels and attempts to work on electronics understands the pain of lugging along the required equipment.

Software flexibility

Though some would consider this a drawback, I'm enamored by the idea of an all-software oscilloscope. This makes the navigation of the charts a bit more cumbersome (using scrollwheels on a 3 button mouse will help), but overall it allows a range of flexibility and multiple views on your data. For the extra ambitious, there is a scripting console in Waveforms 2015 where users can use Javascript to control the various devices on board. Other programmatic interfaces are possible via the API; there are examples in the Waveforms 2015 reference manual.

See it in action

Though these were not official course videos, I did some live-streaming of explorations of the AD2. As I mentioned in the video above, we'll be releasing more official videos in the months ahead.

Questions?

Contextual Electronics has a free and open forum for discussing electronics projects. Use the link below to access the forum thread associated with this post and ask questions about the bundle on offer.

Welcome to CE 3.0

Chris Gammell — Wed, 03 May 2017 14:38:29 GMT

Note: this post is from 2017 and the site has changed many times since then. It's kept here for posterity.

This is the third incarnation of both ContextualElectronics.com and the Contextual Electronics program. The program and the website seem to move in lock-step because of how important the delivery mechanism is for the content. In each version of the site (see the Wayback Machine for how the site has looked in the past), the content has been about delivering project-based instruction around electronics. In this version we are focusing on a few new things:

Using a separate skills-based library - Much of electronics is about practicing various skills over and over again. PCB layout, soldering, programming, choosing parts, simulations...all of these things come up again and again while doing project based instruction. We have broken them out in the CE 3.0.
Using a separate forum - This and every other version of CE has been built upon Wordpress. While the content management system and the available plugins has removed the need for a fully custom site, it also was always very limited on the availability of a proper forum solution. We wanted users to be able to interact with one another, but the software was limiting. For CE 3.0, we have implemented a Discourse forum (the same software that runs the KiCad User Forum). This is still tied to the posts and courses that appear on the main site. Most importantly, we are allowing access for users outside of Contextual Electronics (ie. anyone can register on the forum site). We will write more on this in future posts, but are hoping that the forum will become a resource for all people looking to get started on their electronics journey.
Allowing direct tutoring at any level - The past versions of Contextual Electronics tied the tutoring from the CE instructors only to the members at the very highest tier. In retrospect, this seems silly. The users that are just getting started and likely to be signed up for the lower tiers of content are some of the most likely users to need one-on-one instruction. This is now broken out as a separate purchase and any user can sign up for weekly meetings with an electronics instructor.
Directly tracking course progress for each user - This was a feature available in CE 1.0 but was removed in CE 2.0 to attempt to drive greater integration of the forum and the course content. We have implemented a learning management system that will show each user which module they have marked complete, allowing them to easily see where they left off. This is also shown on the right column for all course modules to easily show how much content is remaining and to allow users to navigate forward and backward in a particular project module.
Focusing more on individual modules - Each incarnation of the site seems to move to smaller and smaller projects. This is not because a small project is "easy" (difficult projects are in the queue!). It's because members can start and finish the projects without needing months of dedication. The reality is that Contextual Electronics is not like a University program: most users will not be able to dedicate months of their lives towards building a single project with no guarantee of success. We have broken out projects into digestible chunks of content, each still focusing on making a board that functions at the end of the project. This is accentuated by the new CE header, which will enable small projects with quick turnaround times.
Better logistics - The back-end processing and access management of the past versions of the site was always a bit cumbersome. The newest version of the site allows switching between various subscription levels with ease, swapping out payment methods easily and many other self-serve options. We are also running on an updated and optimized webserver, meant to deliver content at a much more consistent speed.

There are many things that are staying the same:

Using low-cost, accessible tools - Using KiCad and readily available test equipment and hand-tools.
Implementing project based instruction - All instruction will still focus on pairing theory and practice simultaneously. For any theory that is not already covered, it will be referenced at the point where it's needed (Just in time learning)
Direct access to instructors -While the forum is the preferred method of communication for all content based questions, users can email support@contextualelectronics.com at any time.
Allowing easy payment options - We still use Stripe to implement our subscription payment system.
High quality video - We are still using Vimeo to store and deliver the various videos used for course content.

We are excited for this next version of Contextual Electronics. We think it will allow more efficient learning and greater connection between members of the program. Please let us know what you think!

(KiCad) Information Wants To Be Free

Chris Gammell — Mon, 28 Jul 2014 04:39:02 GMT

TL; DR: I am releasing all of the KiCad videos that were part of Contextual Electronics to the public and have started a new site/forum to support them. See below for announcement video. I officially finished the first two sessions (1A & 1B) of Contextual Electronics in early June. It was a great experience, especially for a first time course, especially one where there was money involved and I was the IT guy on the project. It wasn't a super smooth build, but that kind of added to the project; we were all "in it together". At the very least, I can very confidently say I don't regret quitting my job to teach electronics; it has been rewarding and an eye opening experience. The first part of the course (session 1A) was all about how to design a PCB for a particular application. We use an open source PCB CAD program called KiCad. The open source was important to me because it not only meant that members would be able to download and use the software free of charge, it also meant the final product--which is licensed as open source hardware--could also be replicated and improved upon without needing to buy a license for the software that designed the product. I had been a fan of KiCad long before starting the course and the software has been in development long before that (since 1992!). But it has never really taken off either in the professional nor the hobbyist community, the latter being the more perplexing data point; the predominate piece of CAD software with electronics hobbyists is CadSoft EAGLE. I think it's a good piece of software and have used it a bunch for previous designs, but also think KiCad has surpassed EAGLE in many ways. Not only am I a fan of KiCad, I also see how fast it is moving. It is a dynamic software environment, with developers who are regularly working to make it better. In fact, CERN recently added resources to assist in the project and have been rolling out some exciting new features. They are helping to inject some advanced techniques into the package, which should help move it towards being a world-class piece of CAD software. So between enjoying my own use of KiCad, educating others how to use it and still not seeing it take off, I decided that I am going to release all of the videos that were part of Contextual Electronics about KiCad onto YouTube. I hope that these will encourage people browsing YouTube for help with KiCad to take a deeper look and start using it for all of their projects. I will also add move videos as newer features become standardized and new stable builds are released. The other thing I noticed that was missing was a place to discuss KiCad. There is a Yahoo group but I am not a big fan of Yahoo groups nor how they are run. So I decided to start up a new site with information on how to do the builds and a forum where people can discuss KiCad and the videos I posted. It is meant to be a resource for people getting started who want to build their own PCBs with KiCad.

So that's all for the big announcements today. I will be over at the new KiCad.info forums, answering questions and supporting the site. I hope you will join me over there!