Generating G-code With Common Lisp

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Ruin & Wesen are a two person shop creating specialized music gear. As part of their recent MIDI Command development, they got into case manufacturing. They purchased a mini CNC mill to cut the aluminum cases. Unhappy with the software options provide [Wesen] decided to write his own G-code generator. G-code is part of the numerical control used to command CNC machines. He implemented his interpreter using the language he’s most familiar with: Common Lisp (not surprising if you notice the website’s backend). The post covers the design philosophy used and some of the problems that came up. We look forward to future releases since the interpreter can generate milling code using processing.org sketches and cut PCBs directly from Eagle.

You may remember Ruin & Wesen from when they shared their Eagle layout videos.

[Thanks fbz]

Ferric Chloride Etching Chemistry

[ladyada] has republished an interesting snippet from the synthDIY mailing list. [David Dixon] discusses the actual chemistry behind ferric chloride based home circuit board etching. He concludes that ferric chloride is essentially a ‘one-shot’ oxidant. It can’t be regenerated and can be difficult to dispose of properly. The use of acidified copper chloride is a much better path and becomes more effective with each use, as long as you keep it aerated and top up the acidity from time to time. This etchant solution is actually the result of initially using hydrogen peroxide as an oxidant along with muriatic acid. You can see us using this solution in our etching how-to and while creating the board for our RGB lock. For more information on using hydrogen peroxide, check out [Adam Seychell]’s guide and this Instructable.

Aside: [ladyada] has added the receiver code to the Wattcher project page.

How-to: Prepare Your Eagle Designs For Manufacture

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Cadsoft Eagle is a multi-platform freeware circuit layout program. Lots of open source hardware is designed in Eagle, and it’s become a hobbyist favorite. We use it for all of our hardware designs.

There are several ways to turn an Eagle design into an actual printed circuit board (PCB). We’ll show you how to save Eagle designs as industry-standard gerber files that are accepted by any PCB manufacturer. You can use the gerbers to order a single prototype, or a full panel.

Continue reading “How-to: Prepare Your Eagle Designs For Manufacture”

A History Of SparkFun Prototypes

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If you haven’t checked out SparkFun Electronics’ prototype collection yet, you’re missing out. They unearthed many of their old prototypes and published them to show what kind of mistakes could be made. You’ll see plenty of errors and get hints on what to look for while developing your own hardware. This pairs well with their Design for Manufacture post. Along with the pile of broken board iterations, they also walk through how the company developed. Finally, they specifically cover the individual iterations of the BlueSMiRF.

One of the interesting modules in the gallery that never saw full release was the SparkFun Toys line pictured above. The individual units used the standoffs as the power and data bus. The four posts were arranged so they could only be connected in one orientation: power, ground, TX, and RX. It’s an interesting idea that seems like it might be worth exploring further. SparkFun says that it worked fine, but didn’t feel they had the resources to market it to the intended audience.

Uv Oven From An IKEA Cabinet

This may not be an amazingly complicated project, but it is a very elegant and fairly cheap way of building a UV oven for exposing PCBs. [aris] started with an IKEA FIRA cabinet. He basically left the framework as an empty shell and made a make shift top hinged door to enclose it. Mounted in the top is an array of 35 UV LEDs powered by an HP printer transformer.  He did not have a timer circuit, instead he just watched the clock and unplugged it at the right time. You can see from his pictures that his results were quite good.

If you don’t want that piece of furniture taking up room, and don’t mind using a little more elbow grease, you could follow our directions on how to make your own single sided PCB. If money isn’t an issue either, you can always just get your PCBs laser etched.

Laser Etching Printed Circuit Boards


While we hope you enjoyed our How-To: Etch a printed circuit board, toner transfer certainly isn’t the only way to get the job done. [Garrett] from macetech has recently been playing around with using an Epilog laser to etch PCBs. He started by applying a thin even coat of flat black spray paint to the copper board. The laser is used to remove paint in areas that you want the copper removed. Once that’s done, you proceed with etching as usual. He eventually removed the paint mask using acetone. The result has very fine, sharp traces, but most people that have tried this agree that using spray paint is less than ideal.

StickDuino, USB Stick Arduino Clone


The Arduino hardware clones keep rolling in. This weeks entry into the modern dev board’s roster is the StickDuino. The board is designed to be fully hardware compatible and plugs directly into your USB port. The StickDuino uses all SMD components. The creators know that this can make assembly more difficult so they’ve space the components out, opted for larger pads, and collected some links to SMD tutorials. The board feature two more analog inputs than the Diecimila and it has a jumper so you can switch it to 3.3V. All around it looks like a great product; frankly we love anything with full board layouts.