Free PCB Sunday: Pick your PCB

KHOS-2-3-4-5-6P-600x400

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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: USB device design checklist

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Application note(PDF) on the design of various USB controllers from Microchip.

The purpose of this application note is to provide a list of items that need to be considered when designing systems that incorporate the following categories of Microchip USB products:

-USB 2.0 Hubs
-USB 3.0 Hubs
-Flash Media Controllers
-Flash Media Controller Hub Combo
-USB Transceivers

The target audience of this document is system engineers and layout professionals who are familiar with industry standard practices. This application note must be used in conjunction with the device data sheet, reference design, and other relevant application notes.

App note: Using a hardware or software CRC with enhanced core PIC16F1XXX in class B applications

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An app note from Microchip: Using a hardware or software CRC with enhanced core PIC16F1XXX in class B  applications (PDF!)

Class B safety routines are increasingly used in microcontrollers to detect faults in safety-critical applications. The primary method for detecting faults in microcontroller program memory is by using a Cyclic Redundancy Check (CRC) as defined by the IEC 60730 standard.
A CRC can be used to prevent application faults due to corrupted program memory by performing a periodic check to determine if the check value has changed.
This application note will describe how to implement the Software CRC available as part of the Class B Safety Software Library and the hardware CRC used in selected microcontrollers (this document will focus on the PIC16F161X family).
Both methods discussed in this application note satisfy IEC 60730 spec H.2.19.3.2 to test Invariable Memory for all single-bit faults with 99.6% coverage.

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.  The coupon code usually go to Facebook ‘Other’ Messages Folder .  More PCBs via Twitter on Tuesday and the blog every Sunday.

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

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

Wavetek 1045 RF power meter teardown

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Kerry Wong did a teardown of a Wavetek 1045 RF power meter:

I bought a Wavetek 1045 RF power meter off eBay a few weeks ago. It came with a 13787 detector which is capable of measuring RF power between -50 dBm to 10 dBm with a frequency range of 1 MHz to 18 GHz.

Compared to the ubiquitous HP 436A, which I did a teardown of a while ago, the Wavetek 1045 was from roughly the same era (late 70’s to late 80’s). Although this unit was made in the late 1980s which is about 5 years later than the manufacture date of my HP 436A.
Unlike the 436A, which uses a thermal couple as the sensing element in the RF power head, the Wavetek 1045 uses a Schottky diode based design. The 13787 detector is a single diode detector. There are also balanced (dual diode) detectors available (e.g. 15177), which offer 6 dB higher dynamic range and better measurement accuracy.

Using the RTL-SDR dongle to detect meteors

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According to AMSAT-UK, “a new paper has been released by Dr David Morgan 2W0CXV on using the RTL2841 DVB TV Dongle as a SDR processor with SpectrumLab.

The paper ‘Techniques for using the RTL Dongle for Detecting Meteors’ covers the setting up and use of the dongle to receive meteor pings from the Graves Radar on 143.050 MHz.”

The paper is available for download from the Meteor Detection Projects page of the BAA-RAG website.

CCC video – Fernvale: An Open Hardware and Software Platform


At the recently concluded CCC conference in Hamburg, Germany, bunnie and Xobs presented their “lawful method for converting closed IP into open IP.”

We introduce Fernvale, a reverse-engineered, open hardware and software platform based upon Mediatek’s MT6260 value phone SoC. The MT6260 is the chip that powers many of the $10 GSM feature phones produced by the Shanzhai. Fernvale is made available as open-licensed schematics, board layouts, and an RTOS based upon the BSD-licensed NuttX, as well as a suite of open tools for code development and firmware upload. We discuss our technical reverse engineering efforts, as well as our methodology to lawfully import IP from the Shanzhai ecosystem into the Maker ecosystem. We hope to establish a repeatable, if not labor-intensive, model for opening up previously closed IP of interest, thereby outlining a path to leveling the playing field for lawful Makers.

For a more detailed explanation of their method and purpose, visit the CCC 2014 webpage.

Holiday tunes from Attiny13 and SPI Flash

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In clearing up the year-end mail, we noted this from Vinod sharing one of his recent hobby projects. “This is a holiday hardware hack creating WAV music player using a 512KB SPI Flash he cobbled from a damaged digital camera and the Attiny13 MCU. I implemented UART for song updating…. It is a hack with multiple bitbanging and multiplexing. Please have a look at the project link.

Via the contact form.

Nixie Tube Thing – Dirty PCB to the rescue!

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Crawford writes:

I have been lusting over the Nixie Tube Driver that Ian brought to the 2012 World Maker Faire. When I met him there I asked about board production, but he explained it was a one-time thing. Fair enough.

Well it’s 2014 now and DirtyPCB exists. I grabbed the design off the forum, and shot it off to DirtyPCB for fabbing. Attached you’ll see the first build driving some old nixies I had in the vintage drawer.

I dropped the PCB design in the DirtyPCB store. (Of course, I take no credit for the design – it’s all Ian). If you want some, go buy some!

Thanks Ian! Thanks Open Source Hardware! Thanks DirtyPCB!

Happy New Year All !

Via the project log forum.

#FreePCB via Twitter to 2 random RTs

buspiratev383

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:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

WiFi IoT 3 channel relay board with MQTT and HTTP API using ESP8266

Martin writes:

The ESP8266 DHT22/LED blinker project grew into a M2M relay board project with the following features in mind:

  • Relatively small (10x5cm) PCB
  • Powered via on-board power supply or externally via a micro-USB plug
  • Has three 2A Sharp Solid State Relays (later version has 8A SSR)
  • DHT22 humidity/temperature and/or DS18b20 temperature sensor support to use for thermostat purposes
  • WiFi (of course) in Static/Dynamic IP mode
  • Native MQTT support (both publish and subscribe, controlling the relays and reading sensors over MQTT)
  • HTTP/JSON API for setting/getting relay board properties
  • Fancy jQuery UI for remote control via smartphone/tablet/laptop from anywhere in the world
  • Web-configurable WiFi/MQTT/Sensor settings
  • NTP support
  • In the pipeline
    • Basic HTTP authentication to protect the web interface
    • Dynamic DNS support so that the module’s IP is always known
    • I2C status display support
    • Custom made plastic box/cover
    • Scheduling functionality

On the second day of Taobaomas

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It is 8:30pm in China. Time to review today’s Taobaomas haul. Taobao recently started taking foreign debit and credit cards, so for the first time I feel fully Taobao-enabled.

Today we have another load of food imports. Hope thus isn’t annoying you too much, I just want to show the variety, price, and speed that stuff comes when you’re in China. All the food will be used for a ‘Western Food Party’ for local hackers and our manufacturers and suppliers this Friday.

First up two types of beef jerky from Mongolia. Super beefy, not at all what I expected. More below. Continue reading “On the second day of Taobaomas”

Numato Mega New Year give away 2015 – Grab your surprise gift

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Numato is hosting a ‘Mega New Year give away 2015‘.  Two random lucky winners will receive Waxwing Spartan 6 FPGA Development Board. Another five lucky winners will receive Mimas V2 Spartan 6 FPGA Development Board. And ten lucky winners will receive PIC18 Microcontroller Development Board.   Visit the contest info page for details.

Again that time of the year has come. Christmas is here, New Year 2015 is around the corner. And one more reason to be happy, this is the time Numato hosts the largest give away of the year. That is right! We hosted our 2014 Christmas/New Year give away during December 2013/ January 2014 time and we saw overwhelming response from our readers. We gave away random gifts to every single person participated in the event, 250+ electronics enthusiasts. We hope that everyone who received the gifts put it to good use and learned something from it.

A Classie WSPR transceiver

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joesugar over at Computer/Electronics Workbench writes:

Because of my location, amateur radio operations are limited to low power and disadvantaged antennas. Therefore, the WSPR (Weak Signal Propagation Reporter) protocol immediately caught my eye when I first ran across it. My primary interest is building, so I put together a stand-alone beacon using an Arduino and AD9850 DDS module and ran it for a while on 30 meters but got tired of having to manually switch the antenna every time I wanted to go from transmit to receive. Eventually I decided what I really needed was a low-power transceiver I could dedicate to WSPR operations.

On the first day of Taobao Christmas

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Taobao, the Chinese shopping site that combines eBay, Amazon, and Alibaba, recently got a lot easier for foreigners to use. As Sjaak documented in his Taobao buying adventures a few years ago, most foreigners use an agency that takes payment via Paypal, purchases your babies, and forwards them to you via DHL or airmail. Even foreigners fortunate enough to be in China withdraw money at an ATM, deposit in a Chinese bank account (or buy scratch off value cards), transfer money to Alipay, and then pay for babies – plus a week to set it all up. In short, even with Chrome’s built in translation it’s very difficult for foreigners to shop Taobao.

Sometime late this year, likely around the Alibaba IPO, Taobao started accepting foreign Credit cards as a payment source. Jelmer, second hacker camp participant and now resident hacker, was the first to point this out. I signed up and ordered a ton of stuff that’s raining in over the holidays.

The basic process:
1. Register for a Taobao Account. If you are inside China it is best to use a VPN that shows you outside China. We used a Tokyo exit point.
2. Verify your cell phone number. If you are inside China on a VPN it is still OK to use your Chinese number.
3. Buy some babies and checkout. You will be asked to set a new Alipay password.
4. Near the top of the Alipay payment source page select the last option of the drop down: international payment sources.
5. Enter a credit card and make payment. If you have a Verified by Visa password or some other garbage you will have to do it your first few purchases.

That’s “it”, however as almost no sellers ship outside China you still need to be there, have a friend there, or beg Suzie Shipper to freight forward for you. I’m lucky, and will be here a while on business so let’s get to the shopping.

Most of my holiday Taobao purchases are food related. You might even infer some homesickness by the large number of hometown food imports. First up, this lovely deli meat slicer, $40. You’ll find out why as supplies for the DP deli roll in over the coming days.

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And here’s some extra crunchy super chunk Skippy peanut butter, about $5 with next day shipping. It’s not that there’s no peanut butter in China, even small stores have American brands, but the super chunk is a rare beast.

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No, we didn’t order 6 liters of shelf stable whipping cream, but we got it. This one will have to go back to Beijing, a bit of a pain.

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A six pack of Sierra Nevada Pale Ale. At $5 per bottle plus $3 shipping we’re much better off going to City Super in Shatin, Hong Kong and grabbing them for $2. This is our first Taobao fail.

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Corn tortillas, $3. Not frozen as advertised (err… translated…), though they are cold in Styrofoam (yuck) with an icepack.

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Finally, two jars of Turkish sweet paprika paste, $6 each + $1.60 overnight shipping. Needlessly wrapped in a ton of Styrofoam. This is kind of a weird one, I like to use a tablespoon in pressure cooker risotto and a quarter cup in tomato mother sauce. Hungarian paprika would be better, but I couldn’t find it.

First day haul of Taobaomas was pretty good. This stuff shipped from as far north as Beijing, and arrived in under 24 hours at an average shipping cost of $2 per package. Pretty amazing.

Packaging was overkill and I’m apprehensive about how much Styrofoam will be used to package all the perishables that will arrive in the coming days.

Keep an eye out every day this week for an update on what rolls in. If you have a Taobao challenge post it in the comments and we’ll try to find it!

Merry Taobaomas!

Reverse engineering the Panasonic AC infrared protocol

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The AnalysIR Team hailing from Dublin, Ireland has just published a new article called. “Reverse engineering the Panasonic AC Infrared protocol”. If you’re into IR hacking with the USB IR Toy, check this out.

“AnalysIR is an advanced IR analyzer & decoder that works with Arduinos, Raspberry Pi, USB IR Toy, Teensy3, ChipKit Fubarino and the TI Tiva C + MSP430-F5529 LaunchPads (beta) connected to a Windows PC.” More information and download links can be found on the AnalysIR Team’s website. (NOTE: we realize it’s not open source/freeware, but it IS some pretty cool work product from a fellow hackerspace.)

Via the contact form.

Free PCB Sunday: Pick your PCB

KHOS-2-3-4-5-6P-600x400

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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Decoupling solutions

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App note (PDF) from KEMET on different decoupling capacitors for each board power line requirements.

Integrated circuit (IC) technology has advanced over time, requiring innovative decoupling solutions that address decoupling needs over the entire power path from the main power supply to the logic gates on the IC. As one follows the path from the power supply to logic gate, high-frequency content increases, required capacitance falls, and the importance of very low inductance (ESL) increases. Impedance (Z) must also remain low and stable over the frequency range of interest so that detrimental resonances are avoided. Four tiers or levels of decoupling have been defined along the path from the power supply to the logic gates on the IC: (1) the voltage regulator level, (2) the board decoupling level, (3) the IC package decoupling level, and (4) the IC on-die decoupling level. Each level has impedance requirements that are best addressed by capacitor technologies which differ in capacitance density, capacitance stability, ESL, ESR and cost.
This paper addresses the relative performance of competing capacitor technologies for board level (2) and IC package level (3) decoupling. New decoupling paradigms are presented for both of these levels.