If you make a lot of prototyping, especially with SMD components like myself you need to make for each design its own pcb. With SMD’s the one layer design usually isn’t feasible and since the component pins doesn’t run trough the board  the double layer approach results in many vias, even for a simple schematic you can have 50 of them.

Off course everybody can order from the factory trough hole plated pcb and they are off the hook, that is the professional solution and for the end product I do the same. But that costs more, there is a lead time and if there is some error on the board or on the schematic, you need redesign and order another one.

I personally use home-made double layer pcb’s for my prototypes, with photo method and some design constraints like track width, spacing,  clearance, the results are quite good.

Double layer pcb home made vias

Yes, that’s nice but it has a lot of vias, and can be painstaking  to make the connections for each via by running  through a thin wire, soldering one end then soldering the other end, cutting down the excess, because for each via you have to handle the wire, the soldering iron, the cutter resulting a great “overhead”. I admit this was my solution and took hours to make each via separately, until somebody showed be a clever trick, but that’s enough talking, here are the pictures:

You need some thin copper wire:

You need some thin copper wire:

First anchor one end of the wire by soldering to one side:

First anchor one end of the wire by soldering to one side:

Run through the vias(like sewing) the wire:

Run through the vias(like sewing) the wire: Run through the vias(like sewing) the wire:

Solder each end:

Solder each end: Solder each end:

Start cutting as close as possible(on each side):

Start cutting as close as possible(on each side):

The result:

The result

Nice, round bumps :)

Nice, round bumps :)

And after soldering the TQFP package:

And after soldering the TQFP package:

As you can see, the vias underneath the TQFP doesn’t cause any problem, although more attentions is needed when soldering. Fast and simple, hope you get the spirit and start tinkering.

February 18th, 2010

Mobile 2.4 GHz Spectrum Analyzer

Mobile 2.4 GHz Spectrum AnalyzerMobile 2.4 GHz Spectrum Analyzer

Miguel writes :

The analyzer has become my best travel companion. It’s very discrete: everyone think you are playing with a mobile phone!. You can see in a moment what are the used frecuencies / channels at your location. One of the most interesting things if to carry it in the pocket in exposure mode and walk sometime in your neighborhood. In this way you can find easily what are the free frecuencies or channels. With the time, I learned how to distinguish between different device

Mobile 2.4 GHz Spectrum Analyzer: [via HackADay]

protostack AVR 28 pin board

You may recall, almost a year ago we did a review of Protostack’s ATmega8 development kit. You can read the original review here. Well it turns out that they have been busily churning out new versions of this board, with version 1.4 being released, just the other week. This version has got many improvements over the one we reviewed. Some of the recent improvements include a power supply block for L7805 and the like, a 2×3 pin ISP port and a section for dual row headers or IDC connectors. The board still retains the same great features that we saw in version 1, like the large breadboard style prototyping area and the power busses that are routed throughout. It is available by itself or as part of an ATmega8 or ATMega168 development kit. With both kits being under $20 and the board itself under $10, it is still quite affordable.

DIY Mp3 Player Based On PIC16F877

This pocket sized mp3 player is based on Microchip PIC16F877 and comes with both C and Assembly source code but the C code version has more features and stability. The mp3 player was designed to work with compact flash cards up to 100 gigabytes. For decoding it uses the VS1001K chip and for conversion it uses the built in DAC. The principle of operation is not very complicated, the PIC reads the CF card and once it finds a file it clocks the card 512 times per sector sending all the information one byte at a time to the decoder chip. The decoder gets a valid stream of data and sound comes out of the built in DAC. The project doesn’t have a display or a fancy menu, it’s just a plain simple mp3 player.

DIY Mp3 Player Based On PIC16F877: [link]

January 24th, 2010

Well equipped shop

Very well equiped shop

This has to be one of the most well equipped shops I’ve ever seen. At the moment I don’t have the space to host such a well equipped shop so I have to deal with the minimum requirements but someday I hope I’ll have the space to equip my shop with such a variety of tools. You can view a slideshow with all the different angles here.



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