Spiff's Electronics Notebook

New PCBs and Yellow Soldermask (May 22, 2008)

A panel with 5 fresh new products just arrived from Gold Phoenix.

Firstly a comment on the yellow solder mask: Black, Blue, and Green are my staple solder mask colours, but it's nice to branch out sometimes and I went with a yellow mask for this order. My initial impression is that it looks OK on the copper portions of the board, but the masked bare laminate is unimpressive. While it adds variety to the lineup, it definitely looks cheap compared to even the green mask (which is cheaper) and very cheap compared to a blue or black mask. I'm left with a single-sided paper-laminate feeling.

The new projects are, clockwise from the top left:

• A thermistor based high/low temperate tracker for the -5°c to 30°c range.
• A 555 based high-voltage (48V to 250V) switch-mode boost supply.
• An NCP1400 based 5V step-up controller. I'm not sure if I'll push this design for kitting.
• The 3.3V version of the popular FT232 USB to TTL converter.
• A constant current controller. When hooked between a load and ground, this allows you to set a particular maximum current level regardless of supply voltage or load variances. This is ideal for loading SMPS, LEDs, Laser diodes, etc.

Gold Phoenix kit PCB SolderMask
Posted by spiffed at 12:58 PM | Comments (3)

Restricting via placement in Eagle (February 26, 2008)

Vias are a useful tool when laying out a pcb, but if there's a via in the middle of your text, the effect isn't pretty. This is an especially common occurrence when using and auto-router.

There are a few solutions to this, the easiest is not caring. A harder to execute, but similar solution is to integrate the via into your text.

Finally, in eagle, you can use the vRestrict layer to keep via's out of your text.

Continue reading "Restricting via placement in Eagle"

Eagle Howto PCB
Posted by spiffed at 8:15 PM | Comments (0)

Eagle Postscript Cam Job (January 31, 2008)

On occasion, I etch a circuit board using the toner transfer method. This, unfortunately, usually takes several steps to go from eagle to gerber plots to printable file to printer. With this in mind, I present the postscript cam job for eagle.

Simply unzip the cam file to your cam directory. When you're ready, open the ps.cam file from Eagle's CAM tool. The result is three nice postscript files for the component side, solder side, and the silkscreen. The component side and silkscreen files are already mirrored, so just print from your post-script capable program of choice. (Hint: ghostview is a free postscript capable viewer.)

Eagle PCB
Posted by spiffed at 4:18 AM | Comments (0)

Single Sided FT232RL USB-Serial Converter (January 25, 2008)

Unsatisfied with everything else, I present the simple, single-sided, breadboardable, FT232RL based USB to TTL Serial converter.

I know you're thinking "But everyone under the sun makes an FT232 kit!", and you're right. But they all suffer from a selection of problems:

• Double sided boards with tiny vias. Not only are these a pain to solder by hand, they also require perfect precision to etch and drill at home.
• 7 million parts butted as close to each other as the pick-and-place can tolerate. I can't assemble these with tweezers.
• Signals and power brought out to a DIL style header. There's simply no effective way to plug a DIL header into a breadboard. It's a functional system for wirewrap, perfboards, and stripboards but so is a DIP style connection. It's not very helpful for custom PCBs either, since I might as well integrate the whole circuit into the board.
• You get the idea.

The answer of course is to design a simple, roomy, single sided board, with a DIP like fit.

Continue reading "Single Sided FT232RL USB-Serial Converter"

Eagle3D FT232 Kit PCB Serial SingleSided SMD USB
Posted by spiffed at 12:27 PM

On Paper (December 7, 2007)

Somehow I don't think this is what people meant by 'Does it make sense on paper'.

Continue reading "On Paper"

OnPaper PCB
Posted by spiffed at 3:04 AM | Comments (0)

A bigger basic H-bridge (April 12, 2005)

We just don't do small. So when it came to choosing stepper motors, I picked nice beefy 2lb bipolar beasts. Driving these has, however, turned into a bit of a problem.

Continue reading "A bigger basic H-bridge"

FET H-Bridge Kit Optoisolator PCB PIC Transistors
Posted by spiffed at 8:20 PM