Part of the week: AT24MAC402

Another new section starting today- part of the week. There are many other “chip of the week” out there, so here I’ll just mention things that I personally find interesting . They may be chips, or other electronics parts. Today’s find is an Atmel  AT24MAC402/AT24MAC602 – an I2C 2K EEPROM with a stored and read-only  48 or 64 bit EUI address and a unique 128 bit serial number. The parts are very cheap (25 cents)  and serve a very useful role. Say your company is making a product that uses Ethernet. Typically an EEPROM on board is programmed with the MAC (EUI-48)  address during board test. By simply switching to these chips, a step in manufacturing is omitted, saving time and money. Atmel also thought about companies who would like the MAC address be from their own pool of numbers- they would custom preprogram them as a special order. Overall, a pretty simple idea that will save customers time and money!

 

Atmel QTouch tuning using Saleae Logic16

I happened to use an Atmel Qtouch chip in a project recently. The particular part was AT42QT1040, used in a fairly typical application- replacing four tactile buttons with four touch buttons. The chip is literally a “black box” that you give power, connect a few passives to the electrodes and in return you get four digital outputs representing the status of each key. No software to write, and is very simple. This particular feature came up very handy when a customer recently decided to switch from tactile to touch buttons mid-design. Since I was using Altium Designer on this project, the electrodes were essentially a freebie for me. I simply used Atmel Qtouch library, added the rectangular buttons into my schematic as components and Continue reading

OSH Park rules for DipTrace

In response to a few requests, here is a design rules (DRC)  file (OSHPark.zip) I created  when ordering boards from  OSH Park. To load them unzip the file and in Layout program, select Route- Load Rules.  Note that the numbers are based on a somewhat limited information available. (For example I do not have data on the maximum hole size) The settings are as follows: Continue reading

TI Launchpad Booster Pack footprint library for DipTrace

Today’s post is a small DipTrace library i created for some TI Launchpad Booster Packs I am working on. It is modeled after a similar Eagle library posted on www.43oh.com forum.

There are two schematic symbols and three footprints:

Full size covers the whole Launchpad footprint

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Elektronika MK51 calculator teardown

Today we have a teardown of a Soviet calculator Elektronika MK 51( Электроника МК 51) for those familiar with the language.  It was bought new in 1993, worked (sorta) for a few years and just drove me absolutely nuts with its lack of any reliability. The design is supposedly a clone of Casio FX-2500

Front view

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Sharp Memory LCD breakout

As promised, some 3D rendering pictures of the Sharp Memory LCD breakout board I just designed in DipTrace. The learning curve is definitely very short. It’s not always obvious were a certain option or menu item is hiding, but nothing some Googling can’t fix. Overall feel of the tool is that they started with basic functionality and added just enough higher end features to cover the majority of typical design needs. I like it so far.The 3D models are not exact, since I am using what I could find for the parts. Not all vendors are nice enough to provide their models just yet.

The components side

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DipTrace layout and ordering boards from Dorkbot aka OSH Park

Well, my test design is complete and now I need a few prototypes to play with. The usual ways of ordering PCBs are rather expensive, with just tooling fees in hundreds of dollars. The remaining options are a few China based places such as Itead Studio, Seeed Studio ,PCB Pool and Batch PCB ran by Sparkfun, and an OSH Park ran by Laen from Dorkbot. He runs a community PCB service that groups orders and orders them periodically on a common panel, sharing costs between all people. The cost is very reasonable ($5 a square inch) and you get three boards. So a 2 square inches board in three copies will cost you $10 delivered from a US based board house! That definitely opens the door for quick prototyping of pretty much anything! After having used other company’s prototyping services, I must say OSH is also by far the most user friendly. Lets walk through the steps of ordering these boards. Continue reading

Blog update and some musings on EDA tools

Blog updates

Small blog updates this week. The sidebar is now present on all posts, not just the front page for easier navigation. The awesome picture of the Fluke board has now earned its spot as a blog header.I call it the “dancing transistors” banner. Sure beats stock image.

EDA tools choices

In more electronics related news, I’ve been working on a simple board using DipTrace. It’s a new tool for me, so a small simple design/layout and board order will test the waters so to speak. Why DipTrace you might ask, considering I already use high end packages at work such as Mentor Graphics Pads and Altium Designer, or how about Eagle?  Well, for starters my hobby budget is small, and licensing Altium or Pads is well outside of it. I could potentially use Eagle, like everybody else does in the open hardware community, except for two things. Number one, I absolutely could not stand it when I tried it, and number two- the pricing structure is a bit silly. You either get a light version with 2 layers and a lot of limitations for $69, a Standard version for sch+layout for $575 or a professional for $1145. Sure, one could get a hobbyist/non profit version for $169 but first you have to sign a declaration that makes you liable the moment you design a board and sell a couple. Meh, not good enough. And at every level of pricing, there is still a board size limit. Enter DipTrace. The  free/noncommercial license allows 500 pins and 2 layers. For a commercial version, Standard version with 1000 pins and 4 layers is only $345 and the full version with no limitations is $695. There is also an intermediate version that’s $495 and goes up to 6 layers. That to me seems like a much nicer upgrade path should I ever want to design and sell products. The fact that you could just pay the difference in price to go up the feature ladder is very smart as well.

Now back to work. Pictures/board info coming soon

Sinclair PDM35 multimeter teardown

Another Hamfest find is the Sinclair Radionics PDM 35 digital multimeter. Having grown up with ZX Sinclair Spectrum clone, and reading a lot about Sir Clive Sinclair and his creation I wasn’t about to walk by this. If the look of it is a bit calculator-like, that’s because they actually reused a calculator enclosure! This was a  cheap model, selling for 33 pounds in the 70-s and 80s

It's a calcu-err-meter

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