Here’s a (hopefully) complete list of entries in the Open 7400 Competition. Please share your favorites in the comments below, your favorites will receive a special reader’s choice prize. Voting ends in 24 hours.
A few commenters will receive free PCB codes as a thank you for voting.
Check out the list below.
Continue reading “7400 competition: Entries and reader’s choice”
Pietja built a free PICqueño DIP PCB. He also noticed that if the high current IO’s are enabled on the FTDI chip the reset button would not function.
Follow some of our other PICqueno build videos.
If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.
TI Deals is again offering the eZ430-Chronos at half price. This deal lasts for two weeks or until the supply is exhausted.
Check out the TI eZ430 Chronos page or their wiki for more tech details.
There’s an interesting discussion in the forums about enabling the Open Bench Logic Sniffer to work with Bluetooth. The consumer market is being flooded with cheap Android enabled tablets, and it seems like a good idea to use them with the OBLS to make a portable logic analyzer. Pppd is currently working with a BT adapter and a lithium polymer battery to give the OBLS portability.
Via the forum.
Pietja demoed an HD66717 2×16 display using the Bus Pirate v4 in I2C mode. He provides the instructions and data addresses you’ll need to communicate with this and similar I2C displays.
Via the forum.
The BoardX is an open source miniature motherboard that works with a bunch of different processors.
Kevin writes, “We’re producing an open source miniature motherboard similar to Arduino, except that processors come as add-ons and are not restricted to using one or a specific family.” In addition to various MCUs, the project also includes add-on boards for ADC, FRAM memory and a proto-board.
Via the contact form.
Kelvin wrote to us about the new “nicechips” community available at Reddit. They collect links to data sheets of components they find interesting.
Via the contact form.
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters.
Don’t forget there’s free PCBs three times a every week:
You can get IR Toy v2 for $22.05, including world wide shipping.
Arhi posted a roundup of HAKKO 907 (machine translation) soldering irons and compatible clones that are used with HAKKO 937 soldering stations.
Hakko 907 replacement soldering irons are high quality and relatively cheap irons, and there are many compatible clones on the market. Arhi says there is only a slight build quality difference between the original and it’s clones, and they all work perfectly.
All of them use the same ceramic heating element with a PTC temperature sensor. He provided a pin-out for the original and the clones he could get his hands on. He also made a resistance to temperature table based off a clone he used for the measurement, but asks for your assistance checking his measurements if you have access to a original Hakko soldering station.
We’ll be at Home Camp 4 in London this weekend. If you’re in the area pick up free tickets now, Home Camp scored a sponsor so now the event is gratis:
Home Camp brings together members of the technical community interested in using open systems and low-cost, often repurposed hardware to bring about a positive change in the way we use energy and appliances around the home.
Home Camp 4 invites those working with technology (software, hardware or web-based applications) to meet at an informal “unconference” in central London to offer presentations, workshops, mash-ups and hack sessions with the aim of sharing information and furthering the development of the open energy community.
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The event will again take place at the Centre for Creative Collaboration, at 16 Acton Street, London, WC1X 9NG (nearest tube is 500m away at Kings Cross)
Watch the blog for pictures and updates from the event.
Please give us a shout in the comments or contact form if you’ll be there. This is our first “unconference” so we’re not sure what to expect. We’re going to participate with a demo or discussion.
Matseng built a USB capable AVR MCU breakout board from a free xQFP PCB.
If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.
Seeed featured an article about the first open hardware gathering in China on their blog:
This is the very first conference in China about open hardware, and surely will trigger much more events and activities. Hackerspaces are born all over China like bamboo shoots, and spreading the Maker movement in its region, more people interested in Arduino and open hardware even live on it. Thanks to the offer from OW2 and Peter Cheng, people from Beijing, Shanghai, Shenzhen, Harbin and Overseas to form the exceptional open hardware session during China Open Source Week 2011.
This blog demonstrates how to drive a bi-color LED, or any 2 LEDs, by using only one microcontroller pin. Sinking or sourcing current from the LED selects which one will light up. Setting the pin as input turns both LEDs off.
Alternating between 0,1, and high-Z, both LEDs are fully controllable and even dimmable. The article also explains how to calculate the resistor values to get the desired current for the LEDs. The only drawback to this circuit is that consumption will increase because the voltage divider requires current even when the LEDs are off.
Paul Asselin shares a tip for storing Arduino sketches “in the cloud”. He used Dropbox’s free storage to host his Arduino sketchbook. Now he can access it from anywhere.
Via the contact form.
If you got the free STM32F4 discovery kit this site dedicated to STM32 development might be helpful. Geoffrey provides tutorials and examples to get you started with your STM32 projects.
Via the comments.
Gagandeep built a “bad driver” feedback display. It’s a huge 40X16 LED matrix spanning ~80cm in width, and it’s designed to be placed on the rear windshield of a car. The spacing of 2cm between LEDs is enough to ensure that the driver doesn’t have an obstructed rear view.
Using 2 74HC595 8bit serial in parallel out converters to control the 16 rows, and 5 of the same to control columns he built up his LED matrix. The logic chips are driven by a AT89C51 MCU. Check out the video of this project here.
Via the contact form.
Wortelsoft built a free Bus Pirate LCD Adapter v2b PCB.
If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.
Murphy’s law is a undisputed fact of life, and this app note by Maxim explains how it impacts electronics design.
This application note considers off-data-sheet operation of integrated circuits (ICs). It discusses the pitfalls awaiting engineers who have not experienced Murphy’s Law, which is anything that can go wrong, will go wrong at the worst possible time. The article reviews the thought process of an experienced and inexperienced engineer, and how they can make a circuit immune to leakage from environmental contamination, radio frequency interference, and electro static discharge.
The article provides explanations on how to avoid pitfalls common to inexperienced engineers when designing from data sheets. From knowing what various data sheet specifications actually mean to learning how to protect your ICs from electrostatic discharge and RF interference is covered in this app note.
Ulrich Radig from Germany has developed an 8-bit graphics card based on the XC9572 CPLD. In addition to the CPLD chip (the same one used in our CPLD dev board), he added two cache blocks from an old motherboard. (He reports that the SRAM chip CY7C199-15 could be used instead.)
He states, “[t]he graphics card has a resolution of 256×256 pixels and 64 colors (monitor mode 640×480 at 60Hz with a Quartz osc. of 32MHz or 640×480 at 75Hz with a Quartz osc. of 40Mhz).”
Source code for use with the free Xilinx Webpack ISE software as well as schematic and board files are available from Ulrich’s website.
Here’s a link to the Google English translation.
Get your own XC9572XL based CPLD dev board for $15 and start experimenting with programmable logic today.
Via PyroElectro.
We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.
This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB.
You get unlimited free PCBs now – finish one and we’ll send you another!
Don’t forget there’s free PCBs three times every week:
Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.
