Yet Another End Gain Cutting Board

 I got a new table saw. What better way to break it in than ripping down a thousand square feet of MDF (for the laser) and making a new cutting board! 

 

This one is maple, purpleheart, and walnut. I spent some time coming up with the pattern then deciding which way to checker everything together for the best look. The edges were rounded with a 1/4" router bit this time.

Adding oil is always my favorite part. Fun to watch everything pop!

This is the third end-grain cutting board I've made, each progressively more intricate than the last. We still use the first one all the time. The second one was gifted away.

Laser Cutter Upgrade

The tube on my laser cutter started died. It's a consumable item that produces the collimated beam. If I'm replacing it anyway, I felt it would be nice to upgrade it from a 35W (ostensibly 40W--the manufacturers tend to exaggerate) to a larger 50W model.

 

This laser model has a cutout for an extension case, but it doesn't actually fit with the power plug in the way. After a few iterations of tracing, cutting, and prototyping, I designed a 3d-printed enclosure that would fit the opening perfectly. The steel step flashing was secured inside the print to provide grounding.

The first stage is very sturdy and secures to the chassis with three screws.

It's a terrific fit with everything assembled. The power cable connects without any further modifications and the wire on top provides grounding to the internal metal plates. I couldn't be happier with how it turned out. the increased power almost doubles my cutting speed.

 

Star Wars Mind Games

 Riot Games announced a simple board game this year called Tellstones. The gameplay is simple -- my six-year-old picked it up from watching a few rounds. It largely consists of memory and bluffing as the tiles are flipped upside-down and swapped in a slow, deliberate shell game.

The official game features high-quality components and a theme I don't really understand. I rethemed it as a Star Wars game!

I designed symbols for the tiles and engraved them onto black acrylic with a laser cutter. The images really pop once they're painted.

Each tile has blue acrylic glued to its back, which provides a satisfying heft and a neat color contrast when they're face down.

If you have ten minutes, learn how to play and try it out with a few playing cards. You'll find out whether these really are the droids you're looking for!

Ziploc Storage and Fish Feeders

Two smaller projects to share. The first is a simple storage solution for ziploc bags. My wife requested these because the original cardboard boxes didn't fit in the kitchen drawers well.

They fit perfectly and look nice.

An an unrelated note, my son recently got a betta fish. He cares for the fish very well, but I worried about how to feed him (the fish) when we go on vacation (and also my son, I guess). I put together a simple fish feeder that can be attached to the side of the tank.

A small LED blinks to let you know how long until the next feeding occurs. The design consists of a PIC16F15323 microcontroller, a cheap 28BYJ-48 stepper motor, and a homemade PCB. The blue mechanism is 3d printed PETG, which behaves well if it gets wet.

Halloween Props

Well before anyone question whether Halloween would even occur this year, I thought it would be fun to make a Men in Black neuralizer (or "neuralyzer" depending on the source). Halloween outfits that light up are always a crowd favorite and Mrs. Perry had been asking to do a couples costume idea for several years.

The prop design has changed drastically from movie to movie, both in in shape and light color. Rather than reproducing a specific model that no one would remember, I focused on a simple design with a bright light. Something that would be easy to use at night... and very memorable.

I designed the parts in Fusion 360 and fabricated them on a 3d printer. After some sanding and metallic paint, they'll have the polished chrome look from the movies.

The key piece of electronics is a high-power LED, intended for illuminating outdoor stuff like landscaping. The button instantly discharges the capacitor in a single, bright flash. Like a camera flash, it's brief and leaves you seeing a spot afterwards.

I built two models: red and blue. Very bright, very fun.

We're a rumor, recognizable only as deja vu, and dismissed just as quickly. Happy Halloween!

How to Mill PCBs on a CNC Machine

Many of my projects use electronics, requiring printed circuit boards (PCBs). Even if you've never developed electronics, you'll recognize these boards from inside any electronic device you've ever seen. They're covered with electronics and usually green in color (traditionally, board inspections were performs my humans and green provided good contrast).



Although the price of (Chinese) PCB fabrication has dropped considerably over the past decade, it's often beneficial to make this closer to home, saving money and weeks of turnaround time. It's also a fulfilling DIY project if you have the right tools.

Rather than show off a project I've made, in this post I'll explain how milled PCBs are produced using a CNC machine with enough detail that you can try it yourself if you have access to a CNC.

Designing a Circuit

I use Eagle CAD for my circuit design because I purchased a lifetime license back when they offered such things. I believe they still have a free version for non-commercial use, but since they started requiring monthly subscription fees most of the hobby community seems to have migrated to KiCad, an open-source, multi-platform tool. Whatever tool you choose, plenty of tutorials are available online to cover design, which is beyond the scope of this tutorial.



Once you have a design, you'll want to export the layers you care about as a DXF file and import that into your CNC software.

Tools and Materials

All materials can be purchased cheaply from sites like AliExpress, eBay, or, for a premium price, even Amazon.


Firstly, you need copper-clad PCB material. I prefer single-clad, meaning the copper is only only one side of the PCB. If you want to do something fancy, you can try double-clad and worry about the double-sided aligning of CNCing. At the time of writing, a 10-pack of 7cm x 10cm "Single Sided Copper Clad PCB" runs around $7, but the prices have fluctuated upwards quite a bit since the COVID-19 situation started.


For cutting the traces, you'll need at least one PCB V-bit engraver. Now, you may be tempted to purchase a fine 10-degree bit with a sharp 0.1mm tip, but that would be a mistake. Such a fine tip will break nearly instantly and without a microscope you'd never even know it. It'll look fine, but your PCBs will be ugly and won't work and you'll spend hours trying to puzzle out why and when you finally figure it out you'll want to warn others. But you won't be bitter or anything. Okay, maybe you'll be just a little bitter.

What you really want is a 30-degree, 0.2mm tip engraving bit. Tips smaller than 0.2mm will break too quickly and you're not engraving deeply enough for the angle to matter all that much. Search for "PCB V bit" or similar and expect to pay around 35 cents apiece when you buy a set of 10.


You may need a couple different sizes of drill bits depending on what your circuit calls for. Through-hole designs will definitely need these, whereas a pure surface mount design could avoid them altogether. I keep 0.8mm and 1.0mm bits on hand. Despite their size, they last a while unless someone bumps against them. Simply search "PCB 0.8mm" or similar and expect to pay around 20 cents apiece.



Lastly, an edge bit will route the shape of your completed PCB. It's optional since you can simply cut the PCB shape on a scroll saw or by other means, but it's so very worth having this bit. It gives PCBs a professional, finished look to them. These are trickier to search for, but try "PCB edge bit" or see if this link still works by the time you read this. The tip size isn't critical (I have 1.2mm) and these bits last a while. Expect to pay around $1.50 per bit.

Preparing for Milling

It is very important to have a flat, level surface to mill. This means, in additional to leveling your CNC surface, you should ensure the PCB itself is flat. Place it on a flat surface like a countertop and flex it slightly until it lays perfectly flat. You'll find that there's quite a bit of flexibility to the fiberglass substrate.

I like to mill the traces first, since that's the most finicky part. You want to ensure that you're completely cutting through the copper, but not going so deep as to make the traces too small. It also helps to do a lead out, making sure you overcut slightly to avoid any uncut portions at the beginning/end of the trace.



Since there is no silkscreen, I often cut documentation directly onto the board. Drilling is quick and painless. The optional perimeter cut makes the difference between a quick test board (above) and a clean finished edge (below).

3-D Layered Puzzles

I recently ran across a "multi-layer transparent puzzles" Kickstarter project that looked fantastic. The idea looked fun and the creator even provided instructions on how to make your own, so I did just that.


The first step was choosing a design and slicing it up among three separate layers. This took longer than I thought, but resulted in a unique design with a fantastic aesthetic.


I laser cut these out of clear and red acrylic. The pieces combine into three separate puzzles. Separately, the layers appear chaotic. The puzzle is rather challenging (it's difficult to gauge how challenging the puzzle will be while designing). If I do another, I'll probably use fewer pieces and I'll definitely avoid any nearly-symmetric pieces, since it's hard to know if a piece is flipped when it almost fits both ways.


Once stacked on each other, the full design emerges. It's a beautiful effect and sits nicely on my desk until I decide to challenge jumble the pieces and puzzle it together anew.