Integrating A Power Bus Into A Quadcopter Frame

September 17, 2012 by Mike Szczys 15 Comments

When working on flying vehicles weight is always a consideration. [Brendin] found a way to get rid of a wiring harness on his quadcopter, simplifying the assembly while lightening the load. He did it by incorporating the power bus into the frame of the vehicle.

He started with some copper clad board. Because the substrate is a structural component he didn’t want to use a CNC mill to do the etching as it also removes a bit more than just copper. After using the mill to cut out the shape and drill holes he coated the board with flat black paint. This acts as the etch resist, which he sent through a 50W laser engraver to remove the paint and expose the areas he wants to etch. After etching he removed the rest of the resist, and masked off his solder pads with small rectangles of electrical tape. This protects the solder pads from the truck bed liner paint he uses to insulate the copper. He says it works great and plans to use the technique on all future builds.

Etching Brass And Copper With The Etchinator

September 16, 2012 by Brian Benchoff 16 Comments

If you’re in to making your own PCBs at home, you know the trials of etching copper clad boards. It’s slow, even if you’re gently rocking your etch tank or even using an aquarium pump to agitate your etching solution. [cunning_fellow] over on Instructables has the solution to your etching problems, and can even produce printmaking plates, jewelry, photochemically machine small parts, and make small brass logos of your second favorite website.

The Etchinator is a spray etcher, so instead of submerging a copper clad board into a vat of ferric or cupric chloride, etching solution is sprayed onto the board. We’ve seen this technique before, but previous builds use pumps to spray the etching solution and cost a bundle. [cunning_fellow]’s Etchinator doesn’t used pumps; it’s driven by two cordless drill motors sucking up etching solution through a hollow tube.

The basic idea behind the build is sticking a vertical PVC pipe in a box with etching solution. Mount an impeller in the bottom of the tube, drill many small holes in the side of the tube, and spin it with a motor up top. The solution is sucked up the tube, sprayed out the sides, and falls back down into the reservoir. Put a masked off copper board in the tank and Bob’s your uncle.

Not only did [cunning_fellow] come up with an awesome PCB etching solution, but the same machine can be used for etching brass plate for printmaking, and even photoetching brass sheets for model planes, trains, and automobiles. The quality is really amazing; the Instructables robot above was etched out of 0.7 mm thick brass, with an etch depth of 0.35 mm with only 0.05 mm of undercut. A very awesome build that is already on our ‘to build’ project list.

Radio Built From The London Underground Map

September 13, 2012 by Mike Szczys 20 Comments

We love it when PCB artwork is actually artwork. Here’s one example of a radio whose layout mimics the map of London’s subway system.

The build is for an exhibit at the London Design Museum. They have an artist in residence program which allowed Yuri Suzuki time and resources to undertake the project. He speaks briefly about the concepts behind it in the video after the break.

The top layer of copper, and silk screen was positioned to mirror the subway lines and stops on a traditional transportation map. Major components represent various transfer hubs. In this way he hopes the functioning of the circuit can be followed by a layman in the same way one would plan a trip across town.

This may be a bit more abstract than you’re willing to go with your own projects. But there are certainly other options to spicing you track layout.

Continue reading “Radio Built From The London Underground Map” →

Put A Solder Mask On Those Homebrew PCBs

September 10, 2012 by Brian Benchoff 19 Comments

While making your own PCBs at home is one of the best marks of a competent builder, if you want to give your project a more professional vibe, you’re going to need to do better than bare copper traces on a piece of fiberglass. To help out his fellow makers, [Chris] sent in his Instructable on creating a solder mask for homemade circuit boards using a minimal amount of tools and materials easily sourced from the Internet.

[Chris]’ soldermasks are made from UV curing paints he found on eBay. Of course the traditional green paint is available, along with paints very similar to the Sparkfun red or Arduino blue soldermasks.

After brushing the soldermask paint onto his home-etched circuit board, [Chris] printed out the solder mask onto a piece of transparency film using a laser printer. This mask is vitally important if you ever plan to solder your board; by covering the pads you wish to solder, the paint won’t cure and can later be removed.

[Chris] cured his soldermask by leaving it in the sun for a half hour. After the paint was dry, he removed the excess paint covering the pads with a little bit of turpentine and some elbow grease.

While [Chris]’ paint had somewhat of an ugly matte finish, the soldermask does its job, protecting the PCB traces while leaving the pads uncovered and ready to solder.

Etching Your Own PCBs At Home

August 30, 2012 by Brian Benchoff 79 Comments

Etching your own PCBs from copper clad board is nothing new, but the ability to make your own circuit boards at home is so useful it should be part of every maker’s repertoire of skills. The folks over at Hub City Labs in Moncton, NB, Canada put together a workshop covering the basics of home PCB manufacturing, allowing any maker to put a circuit board in their hands in under an hour.

The process starts just like any PCB design – laying out traces, parts, and vias in a PCB designer such as Eagle. When making your own boards, it’s a good idea to make the traces and pads extra large; the folks at Hub City Labs follow the 50-50 rule: 50 mil wide traces with 50 mils of seperation.

The PCB design is printed out with a laser printer (in mirror mode) onto a piece of paper from a glossy magazine or inkjet photo paper. After the copper board is scrubbed to remove any oxidation or oils present, the design is laid face down on the copper and heated with a clothes iron or sent through a laminator.

After the laser printer toner is transferred to the copper, the recipe calls for etching the board with a solution consisting of a half cup of 3% Hydrogen Peroxide and a quarter cup of muriatic acid.

The folks at Hub City Labs put together a great tutorial for one of the most useful skills the home electronics wizard can have, but etching your own PCBs is an art unto itself. There’s a lot of ways this process can be improved, from using Kapton tape to secure the printed art to the copper board, to getting high-strength peroxide from a beauty supply store.

If you’ve got any tips on making your own PCBs at home, drop a line in the comments below.

EDIT: Good job killing Hub City Lab’s web server, everybody. They’re working on getting something up.

BGA Soldering With A Paint Stripper And Stopwatch

August 27, 2012 by Mike Szczys 22 Comments

Having just received a shiny set of PCBs from the fab-house [Devbisme] needed a way to solder the main chip in place. It has a Ball-Grid Array footprint which is notoriously difficult to populate in a home lab. But he makes it look pretty easy and decided to share a video tutorial of the process.

The main tool he used is the paint stripper (heat gun) seen above. Since he didn’t have his own fancy reflow oven he made things work with the gun as his heat source. First he applies a generous layer of liquid solder flux to the BGA footprint on the board. Next he melts some solder onto the tip of his iron and uses it to tin all of the board’s BGA pads. Then it’s time for the critical step of positioning the chip. He uses vacuum tweezers to set it in place, and traditional tweezers to fine-tune its position. From here he heats with the paint stripper for two minutes, starting far above the board and slowly moving closer, with the reverse at the end of the soldering process. Once cool the board is cleaned with distilled water and blown dry with compressed air. After a visual inspection he finishes the application with a 30 minute stay in a 300 degree oven. We’ve included the video after the break for your convenience.

We’ve seen a similar technique used for replacing a chip on an already populated board.

Continue reading “BGA Soldering With A Paint Stripper And Stopwatch” →

Toorcamp: Milling PCBs With KiCad

August 16, 2012 by Eric Evenchick 19 Comments

[Hao] from Noisebridge showed me their CNC mill being used to etch PCBs. Using copper clad board, this MAXNC 10 mill routes the PCB with decent accuracy. This makes for very rapid prototyping of single sided PCBs.

[Hao] designed the PCB using the open source KiCad EDA tool. This was used to draw the schematic, layout the PCB, and generate the Gerber files. Next, pcb2gcode was used to convert the Gerbers to G-code, which is a standard set of instructions for controlling CNC devices. Finally, LinuxCNC was used to send the G-code instructions to the mill. It’s a powerful application of a completely open source workflow.

The PCB being milled is for a pressure based touch sensor. It uses the Freescale MPL115A barometric pressure sensor encased in a rubber housing. This sensor is being incorporated into the Dora Opensource Robot Assistant project, which [Hao] and the Noisebridge folks are working on. We’re looking forward to hearing more about the Dora project in the future.