Silkscreen

Silkscreen has long been used on circuit boards to guide the assembler to know what components go where, as well as to show users details about the board such as where power and IO pins can be found. It’s a small detail that is all too often considered less important than other details of a circuit board design, but it really shouldn’t be.

When a manufacturer is getting ready to assemble your circuit board there will be a lot of details they need to pay attention to. They’ll need to make sure all of the locations that should be populated actually are populated, as well as making sure that any locations that have been marked as DNP (Do Not Populate) are indeed NOT populated. They’ll need to confirm that polarized components such as IC’s and LED’s are being populated the correct way so that they function properly. If there is a problem, they’ll need to quickly identify the location and work out the details of the problem. Silkscreen will help with all of this.

Cozy Silkscreen Parameters

When setting up the parameters of your EDA tool’s silkscreen text, I recommend the following “cozy parameters”. These are not minimums by any means, but if you have the room for it, these are good middle-of-the-road parameters that a PCB fab can easily print and an assembly shop can easily read while also leaving enough room on the rest of your board for your layout.

  • Text Height: 1mm
  • Text Width: 1mm
  • Line Thickness: 0.18mm
Cozy Text Height = 1mm
Cozy Text Width = 1mm
Cozy Line Width = 0.18mm

Visibility

Whenever possible, try to keep the relative reference designators for components visible, even after the components get populated. Make sure that the silkscreen doesn’t get drawn across any open vias or thru-holes. And since silkscreen is usually only printed on top of soldermask, it would be a good idea to keep the silkscreen away from any exposed copper pads. If the silkscreen is too close to the soldermask this will be removed, often called “clipping”. In order to avoid silkscreen clipping, make sure no silkscreen is within about 0.1mm of the edge of the soldermask opening.

Keep reference designators and polarity indicators visible even after parts are populated

Polarity Indicators

Polarity is something that every assembler is concerned about. Silkscreen is usually the first thing an assembler looks for to define the polarity of a component. Having that silkscreen remain visible even after the components are populated is a great way of confirming that everything was done correctly.

Some examples of how to make sure the polarity of components is obvious would be to put a dot of silkscreen near the pin 1 of an IC, put a numeral 1 near the pin 1 of a connector, and put a C near the cathode pin of an LED. There are plenty of other methods, but these are some of the more popular ones.

Examples of polarity indicators

Taking the time to make sure your silkscreen is printable, visible, and legible will save you countless headaches and ultimately result in higher yields, quicker lead times, and less phone calls!


This article is part of an ongoing series of articles that will ultimately end up becoming a book I’m calling “Your Manufacturer Is Stupid”. Click this link to see more articles just like this one.

KiCon 2019

When I’m not brewing beer, I’m manufacturing circuit boards for a living. A lot of what I do every day revolves around how to handle projects that have design flaws. Most everything we build is very well designed, but because we introduce so many new designs to our process every single day, I spent a lot of time working with our team to figure out how to work around these design flaws.

Good thing is, I really enjoy it actually. It’s a fun challenge and I really enjoy working with our customers to come up with solutions to make their designs easier to assemble. With that in mind, I thought it would be a good opportunity to share some of the most common problems we run into while assembling circuit boards and share that with the attendees of KiCon in Chicago on April 26th and 27th.

The title of my talk is “Your Manufacturer Is Stupid – Help Them”. I know, it’s a real obnoxious title but figured it would drive traffic. The main point of the presentation will be to show the audience how many decisions are made during the manufacturing process and how KiCAD users can help their manufacturers answer questions before they’re ever even raised. I’m really looking forward to it and hope the turnout is strong so that we can have a 2nd even next year, and hopefully many more after that.

Earl Dreams of IPA – Post 2

So about that Experiment #4….

Something went dreadfully wrong. Imagine taking a band-aide off your sweaty arm, putting it in a microwave until it gets nice and crispy on the edges, and then chewing on this while drinking a nice glass of water with a few too many pellets of hops dropped into it. Yeah, that basically sums up how well Experiment #4 came out.

Obviously, I got an infection in the beer, which is a real bummer. Had a friend of mine over to taste it and he agreed, something went horribly wrong. It couldn’t have just been the recipe itself. All of the ingredients were solid ingredients. No weird curveballs there. I suspect my brewing partner (my 13 year old pug) may have gotten himself a bit too close to the fermentor while filling and added a fur or two to the mix.

Stay tuned for Experiment #5. This time my brewing partner has agreed to wait upstairs while dad fills the fermentor.

iSpindel Project – Post 2

Whenever it comes time that you want to build a DIY product, you really must understand the bill of materials first. For the iSpindel, it just was not very straight forward. There’s nobody really explaining what everything is and how it’s all used. The documentation for this just doesn’t make it all very clear. So I’ll do my best explain what each electronic part is, what it does, and where you can find it.

The brains of the whole operation is the ESP8266 chip. This tiny little chip packs of a lot of cool stuff in it. But unless you’re an electrical engineer, you don’t want to go out and buy this chip and build a circuit around it. You want all of that stuff done for you. The German folks who first put together the iSpindel were fans of the Wemos D1 Mini. The Wemos D1 Mini is a cool little single-board micro-controller that has all of the various things you need to interact with the ESP8266 chip.

But the D1 Mini doesn’t have the necessary sensors to give you the information you need to take all of your measurements. For that, you need to add a temperature sensor and a gyroscope.

For the temperature sensor, that’s easy. There’s a very popular temperature sensor called the DS18B20. This little guy is super cheap and readily available anywhere.

For the gyroscope our friends in Germany are recommending the MPU-6050 which is a very popular chip. But much like the ESP8266, you don’t want to buy just the chip. You want to buy a daughter board (often called a shield) that has all of the various control circuitry built into it. The GY-521 is a great daughter board for this purpose.

Once you’ve got those 3 main pieces of silicon (micro-controller, temp sensor, gyro), it’s time to power these bad boys. That’s where your Panasonic 18650 battery comes in. This is a hefty, lithium-ion rechargeable battery, packing 3400 mAh into one tiny package.

In order to control this battery, and be able to recharge it, you will want to use some kind of lithium-ion battery controller. Again, our German friends to the rescue. They recommend the TP4056 controller. This is a very popular DIY battery controller module that plays nicely with the Panasonic 18650 battery and the Wemos D1 Mini.

So now we have our silicon, we have our power, it’s time to wire all of these things together and give them an on/off switch. In order to do that properly, you’re going to want a few other electronic components. A solderable breadboard, an on/off switch, a 470 ohm resistor, a 4.7k ohm resistor, and a 230k ohm resistor. If you’re not familiar with resistors, ohm is the unit of measurement and “k” means “thousand”. So when you say 4.7k what you really mean is 4,700. When you say 230k what you really mean is 230,000 and so on.

There are all kinds of switches out there. They’re all dirt cheap and they all usually work really well. That being said, because they’re so dirt cheap, it’s nearly impossible to find just 1 of these at a reasonable price outside of a large electronics distributor’s website. So if you order these from the link I recommend, you’re going to end up with 50 of these. Better get creative with the other 49 of them.

There are a bunch of various solderable breadboards out there, but you’ll probably want one that is designed for the Wemos D1 Mini. It’ll just make your life a little easier when you solder all of these things together.

For the resistors, you could buy each of these resistors individually, but usually you’ll spend just as much, if not more, for shipping these things than if you just bought a kit with all kinds of resistors, so that’s what I’m recommending in my bill of materials.

Finally, you’ll also need a few various sized jumper wires. If you’re really desperate, you can just cut the leads off of some of the resistors you’re not using to make your own jumper wires, but in case you can afford another $10 kit, I’m recommending a popular kit from Amazon.

Once you’ve got all of your electronic parts, you can begin your assembly and write the code to the ESP8266 chip. More details on how to do all of that in an upcoming post, but for now, reference these couples of pages from the community.

I hope you found this information helpful. And finally without any further ado, here is your bill of materials, with all items available on Amazon.

Bill of Materials

  1. Micro-Controller (Wemos D1 Mini)https://www.amazon.com/dp/B01MDRVUQU/
  2. Temperature Sensor (DS18B20) https://www.amazon.com/dp/B077NYFYZS/
  3. Gyroscope (MPU-6050)https://www.amazon.com/gp/product/B008BOPN40/
  4. Battery (Panasonic 18650) https://www.amazon.com/gp/product/B01C4GFVN8/
  5. Battery Controller (TP4056)https://www.amazon.com/gp/product/B00HJNX0DU/
  6. Switchhttps://www.amazon.com/dp/B007QAJUUS/
  7. Wemos Compatible Breadboardhttps://www.amazon.com/gp/product/B07G3227MD/
  8. Resistorshttps://www.amazon.com/dp/B07CBV473M/
  9. Jumper Wireshttps://www.amazon.com/dp/B07CJYSL2T/

Earl Dreams of IPA

When it comes to tasting beer, entirely too much emphasis is placed on the variety of hops used in the brew and in what volume those hops were used. About 5 years ago I had my very first Tree House Brewing Company beers. It was a Haze and I had never tasted anything like it. Although I had a very simple pallet back then (still do) I recognized that something was very special about the yeast character of this beer.

As the years went by and I continued to brew ever all kinds of varieties of beer, I quickly recognized that London Ale III was not the only yeast that THBC uses in their beers. There’s definitely something more going on in there that LA3 is not giving to this beer. LA3 is far too clean for the flavors you get from Haze.

One morning while eating a bowl of Cheerios with bananas, I was smacked in the face with a reminder of Haze. Immediately I realized I had to start brewing experiments to target this yeast profile.

Not alone in the pursuit, I borrowed greatly from those who’ve blazed this trail before me, especially the group on Homebrew Talk and Marshal Bishop over at Trinity Brewers.

So here are links to my first 4 experiments. Note that the grist and hops changed every time as I was just messing around with those ingredients, mostly based on what I had lying around. My real goal has been and continued to be, to isolate this yeast profile. I really feel like with experiment number 4, I’m starting to get close.

iSpindel Project – Post 1

It’s been said that the cold side of making beer is the most important aspect of homebrewing. That means that keeping a close eye on the fermentation process could have a significant impact on the quality of your beer. 

Traditional methods of monitoring your fermentation usually only involve the appearance of the beer, if fermenting in glass or clear plastic, or the bubbles coming from the airlock or blowoff tube.

When the Tilt Hydrometer was released, a whole new world was opened to homebrewers who’d like to get real time data about their fermentation process. The ability to keep an eye on temperature and gravity as the fermentation progresses can give the homebrewer far more information than they ever had before. But at $135 a piece, this means that the cost of that information might be out of reach of the typical homebrewer. 

Enter the iSpindel project out of Germany. An open source version of the popular electronic hydrometer. Needless to say, when a friend of mine told me that this project existed, I could not help myself but dig in deep. My background in electronics, programming, and brewing, made it a no brainer that this should become a project I plant my flag on. 

As we dig into this project further to come up with a more solid and consistent product we will continue to post our findings on this website so that others might learn from us and build an iSpindel of their own.