Free PCB Sunday: Pick your PCB

xQFP50 plus65 Protoboard-W800 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:

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App note: Understanding XC9500XL CPLD power

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Here’s an app note from Xilinx on calculating power consumption for a CPLD.

The goal of this application note is to discuss XC9500XL CPLD power estimation and optimization and provide the reader with an understanding of sense-amplifier based CPLD power dissipation. A brief discussion of the process for estimation is given. With this information, you can accurately assess the power dissipation for a design. You will also be given guidelines permitting you to make key choi ces to manage the power dissipation of your design and understand the package thermal limits.

NSA wants to build quantum computer to penetrate “hard targets”


The Washington Post is reporting that the NSA is building a computer to defeat all forms of encryption commonly used to ensure privacy of personal communications and data. The project seeks to build “a cryptologically useful quantum computer” which would open the door to easily breaking the strongest encryption tools in use today, including a standard known as RSA.

For details and links to the Post’s source documents, visit the Washington Post.

App note: CPLDs as Motor Controllers

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Here’s a simple motor controller implementation using CPLDs from Xilinx.

To enable a CPLD to turn the electromagnets on and off, external transistor drivers must be used. A unipolar stepper motor can be driven by four identical NPN or N-channel drive
transistors. The various Xilinx CPLDs can operate with I/O voltages from 1.5V to 5V. The CPLD capable of delivering the appropriate output voltages should be selected for use with transistor drivers that can accept and understand the voltage.

App note: Xilinx in-system programming using an embedded microcontroller

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Program Xilinx’ CPLDs and FPGAs with the aid from this app note.

By using a simple JTAG interface, Xilinx devices are easily programmed and tested without using expensive hardware. Multiple devices can be daisy-chained, permitting a single four-wire Test Access Port (TAP) to control any number of Xilinx devices or other JTAG-compatible devices. The four mandatory signals comprising the JTAG TAP are: Test Clock (TCK), Test Mode Select (TMS), Test Data Input (TDI), Test Data Output (TDO)
 
The processor and JTAG chain schematic shown above can help designers achieve these unprecedented benefits by providing a simple means for programming Xilinx CPLDs and FPGAs from design information stored in the embedded processor memory space. This design can be modified for remote downloading applications and the included reference C code can be compiled for the designer’s processor of choice.

Magic Mote thermostat and wireless temperature sensor

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Tom’s another cool project the Magic Mote thermostat and wireless temperature sensor:

A homemade thermostat up in the basement rafters controls the heating in my home. The smart bit is the radio frequency communication that connects it to a remote temperature sensor.

So, I’m planning a home automation system based around wireless nodes (the Magic Mote featuring a MSP430G2553 low power microcontroller plus NRF24L01+ 2.4 GHz radio module). Part of the motivation for doing this is that the wires between the furnace in the basement and the thermostat 2 floors up have broken and it’s a terrible nuisance to fish new wires in a 100 year old house with knob and tube wiring inside the walls.

Free PCB coupon via Facebook to 2 random commenters

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday.

Don’t forget there’s free PCBs three times every week:

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OOMP part box

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We had 1000 boxes and part holding trays made up for the new OOMP part management system. These won’t be at Seeed yet, just for our internal use and giveaways, but I wanted to share the result. Each set (box+tray) is about 1.2RMB ($0.20), took about a week to make and deliver.

We asked for white cardboard (not shiny, cheap stuff), they offered coated board for five times the price. That was a no go, but at the last minute they had stock issues or something and offered us white anyways. The sheets were slightly too small for the original tray design so they made the front part a bit smaller, chopping the side artwork a bit. The fit of the tray into the internal box is a bit tight and we’d give it an extra mm on each side in the future.

They were delivered by a van in seven large boxes, so we hired one of the electric tricycle man to move them and carry them up seven flights of stairs.

All in all, not so bad for a first go at creating a box in China in less than a week over New Year.

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CCC Video: Extracting keys from FPGAs, OTP tokens and door locks


This presentation on extracting keys from FPGAs, OTP Tokens and door locks is from the recent Chaos Communications Conference (CCC) in Hamburg, Germany. In it David briefly introduces implementation attacks and side-channel analysis (SCA) in particular, along with related methods to bypass security mechanisms and extract secret keys. “The main focus is on three case studies that have been conducted as part of the SCA research of the Chair for Embedded Security (Ruhr-Uni Bochum) since 2008: The first example are FPGAs that can be protected against reverse-engineering and product counterfeit with a feature called “bitstream encryption”. Although the major vendors (Xilinx and Altera) use secure ciphers like AES, no countermeasures against SCA were implemented. As a second example, a wide-spread electronic locking system based on proprietary cryptography is analyzed. The target of the third case study is a popular one-time password token for two-factor authentication, the Yubikey 2.”

Week in (p)review January 03, 2014

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Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon.

Coming up:

  • Free PCBs via Facebook on Friday
  • App notes on the weekend
  • Free PCB Sunday
  • Free PCBs via Twitter on Tuesday
  • Weekly roundup and preview every Friday

Car proximity v2

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Bithead writes:

The transceiver I created for the original solution was based on an Arduino Uno with an Xbee shield. I put the assembly inside a Sparkfun Arduino Project Enclosure which measures 87x64x28mm. This has worked well for about 1.5 years now, but there is room for improvement:
1. I’d like to shrink the enclosure so it takes less room on the dashboard
2. I’d like to be able to raise the antenna to the vertical position. The windshield prevents this with the current configuration.

Wireless sensor node with MSP430G2553 and 8-pin adapter for NRF24L01+

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Tom has designed this Magic Mote wireless sensor, that is available at Github:

I set out to design a wireless sensor PCB that could be inexpensively prototyped in quantities of 10. NRF24L01+ modules are exceedingly cheap (~$10 for 10), use very little power, and have sufficient range for most indoor projects. Low power MSP430 microcontrollers make an ideal partner for battery powered applications. I settled on the MSP430G2553, but the MSP430G2452 can be substituted whenever hardware UART is not required.

Alarm clock using an OLED

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Markus Gritsch writes:

Inspired by this and this  wrist watch, I decided to build yet another iteration of my bedside table alarm clock, this time using an OLED.

As a first step I made a handy breakout board for an 1.3″ 128×64 OLED. The rest is soldered together on a perfboard.
The hardware is complete and working, the firmware in an early development stage.

Via the forum.

A development board for Lua programming

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doub has been working on a development board for Lua programming:

So this project is about packing a relatively fast microcontroller, but not complex enough to require a high level OS (like Linux for SoC-class chips), with a big RAM chip. I picked a STM32F427, because I have some experience with the STM32 family, the core is a Cortex-M4F (floating point will help running Lua), and it is one of the few Cortex-M microcontrollers with an SDRAM controller. SDRAM is desirable over SRAM because it’s much more dense and there are 256Mbits (32Mbytes) chips available for a few dollars.

Via the forum.

Video: Maker Faire NY 2013: Arduino NFC


In this video from the 2013 Maker Faire New York, Don Coleman takes the stage in New York to discuss Near Field Communication (NFC) using the Adafruit and Seeed Studio NFC shields on an Arduino. Coleman is a software developer and is co-authoring a book on NFC, PhoneGap and Arduino for O’Reilly.

Via Make.