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Feb 26 13

Kicad Tutorial: Copper pours / fills

by Layne

This is part of a series of short tutorials on advanced topics of using Kicad, the favorite schematic/PCB design software here at Wayne and Layne.

A copper pour or fill refers to an area on a printed circuit board where the original copper is not etched away, and remains in place, usually electrically connected to the Ground signal, producing a “Ground Plane”. This has a number of advantages, including decreasing the amount of etching fluid required during manufacturing, as well as reducing the amount of electrical noise and signal crosstalk experienced by the circuit elements.

It is relatively easy to create a copper fill in Kicad. We usually add fills after having already drawn in the PCB outline in the Edges layer. First, ensure that you have selected one of the copper layers (such as “Front” or “F.Cu”). Then, select the “Add Filled Zones” from the toolbar on the right side of the screen.

Select Tool

Next, click in one corner of the PCB outline to start drawing the copper fill.

Click board corner

Once you click in the first corner, the following properties box will appear. Select the relevant copper layer (here, either “F.Cu” or “B.Cu”) and the desired net for the fill (usually you want “GND”, but sometimes you might want some other net, or “<no net>” which will make an isolated copper fill). The settings in the bottom half are important for controlling the drawing of the filled area as well as the “thermals”. One potential problem with adding ground fill is that the ground pads will become very difficult to solder, as the ground plane will suck away all the heat from your soldering iron, and the pad won’t ever heat up hot enough for the solder to flow. To avoid this problem, you almost always want to add “thermal relief” to your ground pads, which means there is a keep-out area adjacent to each ground pad where there is no fill, and instead each ground pad is connected by a number of thinner traces. This still provides a very good electrical connection for the ground pad, but makes it much easier to solder. The “Clearance” setting controls the general clearance between the filled area and pads/traces of other nets. The “Minimum width” setting controls the thinnest that the fill can be when flowing around other pads/traces. The “Thermal Reliefs” settings control the clearance around the ground pads (0.040″ here) and the width of the traces connecting from the fill to the ground pads (0.009″ here). We’ve found these settings to work pretty well for most of our projects. You also want to select “Arbitrary” for the “Outline Slope” setting to make it easier to draw the zone outline. Click “OK” to close this window and continue drawing the fill outline. (Click the image to enlarge)

Zone properties

Once you have closed the zone properties window, click once in each of the other three corners (in order) on the board outline. Then, to complete the final segment, double-click on the original corner to end the zone. You should see red or green hatching (depending on which copper layer you used) on the edges of your PCB indicating the filled region, as shown in the image below.

Outline hatching

Generally you want to have a copper fill on both the top and bottom of the PCB. To add the fill on the other side, the easiest way is to right-click on the existing board edge, select “Zone outline”, then go to “Zones”->”Duplicate Zone”. This brings up the zone properties box for the new zone, so select the other copper layer and press “OK”.

To see the copper fills in your design, click on the “Show filled areas in zones” button, the 10th button in the left-size toolbar. The button below that will hide the fills. Then, you can run the DRC tool (Ladybug Checkmark in the top toolbar) which will fill all your zones. You should see something like the image below. The brown-yellow color is the combination of red (top side) and green (bottom side) copper fills. We can see the 20 mil clearance between the fill and non-ground copper, and the larger 40 mil clearance between the fill and GND pads.

Finished fills


Other tutorials in this series:

Feb 26 13

Kicad Tutorial: PCB edges

by Layne

This is part of a series of short tutorials on advanced topics of using Kicad, the favorite schematic/PCB design software here at Wayne and Layne.

An important part of designing a PCB is to clearly indicate the outline of the board, so the board house will know how to cut your boards apart. Most PCBs are rectangular, but sometimes you want to add a more complex outline (like a circle or hexagon) or a very complex outline (like the PCB for the Video Game Shield, shown below).

vgs_complex

To make it easier to determine where the PCB edges should be, you probably watch to switch your cursor to be the full-screen cross, by clicking the cursor toggle button in the left-most toolbar (6th down from the top).

edges_2_cursor_switch

Then, select the “Edge.Cuts” layer from the list on the right side of the screen. Select the blue dashed line toolbar icon to draw graphic lines in the Edge.Cuts layer. Using the full-screen cross cursor, it is easy to find the corner of your design. Make sure to leave a little bit of clearance between the outer-most components and the PCB edge. Click to start drawing the edges, and click once in each corner of the PCB. Double-click to end the drawing.

edges_3_layer_corner

If your edge lines are not very thin, we suggest reducing their width. Right-click on each line (you might have to zoom in to ensure that your mouse cursor is pointing at the yellow line itself) and select “Edit Drawing”. Then, change the Item and Default thickness values to be 0.001″ each. We feel that this reduces confusion with the board house as to where exactly the board should be cut (“Inside of the thick line? Outside of the thick line? Middle of the thick line?” With a thin line there is no ambiguity.)

edges_4_settings


Other tutorials in this series:

Feb 1 13

W&L Mentioned in Ladyada Inverview with Brad Hines

by Layne

W&L were mentioned in this interview with Ladyada, conducted by Brad Hines:

BH: Name what you would say are the biggest devices behind the DIY movement.

Open-source hardware, this is more general, but there are many companies, from Adafruit to Sparkfun that have release hundreds of open-source hardware products. From breakout boards to watch kits – we’re all putting value back in while we do a great job getting our customers and communities awesome products. We really like Evil Mad Scientist, LittleBits, Wayne and Layne, Seeed, Bunnie studios and many many more who have devoted their passions to sharing hardware.

Read more…

Jan 15 13

Wayne & Layne Forum: Down for the count

by Layne

The W&L forum is basically non-functional right now after an issue at our webhost, and we’ll be re-installing and re-configuring the forum in the next few days. We expect it’ll be back up before Monday, and we’ll post here when it’s ready. Sorry for the the confusion and non-functionality the last few weeks!

Dec 13 12

Assembled Blinky Grids and Blinky POVs from Solderbot

by Layne

Solderbot makes and sells assembled electronics kits. They’re relatively new, and look to be stocking at least one kit from each of the the Minneapolis kit companies I know about!

They’ve got our Blinky Grid and Blinky POV for sale, and the video Luke made is a pretty great introduction to the kit!

Dec 10 12

New store!

by Wayne

Last night, we opened our new webstore at https://store.wayneandlayne.com. We’re keeping the old one up until the end of the holidays, but the new one has the same prices, and works much better!(We’ve since added redirects for the pages, products, and categories, so you shouldn’t be able to get to the old site.)

In fact, you can find the Bricktronics Shield in the new store.

More announcements coming soon!

Nov 22 12

Blinky Grid SMT featured in Adafruit Holiday Gift Guide: Blinky

by Layne

Our friends at Adafruit started releasing their yearly Holiday Gift Guides this week, and the Blinky Grid SMT was featured in their Adafruit Holiday Gift Guide 2012 – Blinky:

Blinky Grid Red SMT from Wayne and Layne: This is the surface-mount version of their Blinky Grid kit, and is a great way to learn and practice surface-mount soldering. While W&L won’t say that everyone can successfully solder surface-mount, you do not need extreme dexterity or super eagle vision. They have built a bunch of these with people who have never soldered surface mount before, between seven and fifty or so years of age – and everyone has been successful!

Read more: Adafruit Holiday Gift Guide 2012 – Blinky

Nov 21 12

Video Game Shield featured in Adafruit Holiday Gift Guide: Arduino Shield

by Layne

Our friends at Adafruit started releasing their yearly Holiday Gift Guides this week, and the Video Game Shield was featured in their Adafruit Holiday Gift Guide 2012 – Arduino Shields:

Wayne & Layne’s Video Game Shield Kit – The Video Game Shield is an Arduino add-on shield to make your own video games, including graphics, text, sound effects, and music! Using the power of open source, this Shield includes everything you need to make awesome black-and-white video games on your TV. It supports up to two Nintendo Wii Nunchuck controllers for an easy and familiar interface.

Read more: Adafruit Holiday Gift Guide 2012 – Arduino Shields

Nov 16 12

Warm fuzzies about the Blinky Grid SMT

by Layne

Thomas wrote in with some kind words about the Blinky Grid SMT kit he purchased at Radio Shack:

Thank you so much for the high quality kits and excellent documentation! I recently purchased your Blinky Grid SMT kit for a teaching engagement – mostly because of the novel programming method! To say the least, everything worked out great. Building the kit was a breeze, programming and demo went well, and the kids I was working with walked away with an increased interest in electronics and programming!

Next up – Video Game Shield! Just need a free weekend! Again, keep up the great work and please, more SMT kits!!

The Blinky Grid SMT (and all the other Blinky kits) are available in the Wayne and Layne Store and also the Maker Shed store.

Sep 10 12

Nice review of the Blinky POV SMT kit by tronixstuff

by Layne

John from Tronixstuff recently reviewed our Blinky POV SMT kit, and really liked it! Here are some highlights from his review:

after my last attempt at working with hand soldering surface-mount components couldn’t really be called a success, I was looking for something to start again with. After a little searching around I found the subject for today’s review and ordered it post-haste.

you’ll want to put your own messages into the POV – and the process for doing so is very clever. Visit the programming page, and follow the instructions. Basically you enter the text into the form, set the POV to programming mode – and hold it up against two squares on your monitor. The website will then blink the data which is received by the light-sensitive LEDs. Once completed, the POV will inform you of success or failure. This method of programming is much simpler than having to flash the microcontroller every time – well done Wayne and Layne.

We had a lot of fun with this simple little kit, and learned a thing or two about hand-soldering SMT. It can be done with components that aren’t too small – however doing so was an interesting challenge and the results were quite fun. So it met our needs very well. Anyone can do it with some patience and a clean soldering iron.

Continue reading… Adventures with SMT and a POV SMT Kit

Photos by John Boxall