Minimalism AVR development board

in AVR by DP | 0 comments


Baoshi of DigitalMe wrote an article detailing his minimalism ATTiny2313 development board build:

The AVR chip I’m talking about is Atmel ATTiny2313, in SOIC-20 package. To make the development board, I bought some 28 pin SOIC/SSOP to DIP adapters. These adaptors usually come in double sided design. Corresponding pins on both sides are connected via the plated through holes at edges.
I made a 2×3 AVR programming header by pulling off pins (longer ones) from a double-row right angle pin header and reinsert them into the plastic base. A needle nose pliers is very handy for this purpose.

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Controlling appliances using text messages

in AVR by DP | 0 comments


A GSM remote control project designed by Vassilis Serasidis:

Two years later I built another one remote control based on GSM module. I choose the GM-47 sony-ericsson module because it was very easy to handle it via AT commands. Moreover, the price was low enough for experiments. Finaly, I decided to release the source code under GNU General Public Licence V3  If you don’t agree with the terms please DO NOT download or use any part of this project (schematic diagram, source code, hex code, PCB, etc).

Via Embedded Lab.

Acoustic impulse marker

in gadget, hacks by DP | 0 comments


Adam Wrobel and Michael Grisanti of Cornell University built this device that tracks sound impluses:

The core of our system is hardware based analog circuit, which filters, amplifies, and processes the sounds obtained from the microphones. By utilizing hardware for this, we are able to high frequency signal processing without taxing the microcontroller. Also, we remove the need to use the relatively slow ADC of the microcontroller by processing all the analog signals in hardware and converting them to binary digital pulses. However, the main tradeoff here is that the analog hardware limited our accuracy in a way that is very difficult to measure. Every stage of the circuit has real world inefficiencies and tolerances, which could accumulate in minute error. No matter how fast or thorough our software system is, it can only work with the values received from the analog hardware.

Via Hacked Gadgets.

Check out the video after the break.

Continue reading →

Hacker Camp Shenzhen volume 3: Reflow open for registration

Hacker Camp Shenzhen volume 3: “Reflow” is on! Join us from Thursday December 4 to Saturday December 6, 2014 for fun, food and 3 solid days of market tours in Shenzhen China and beyond. Tickets are available now.

Come to the world’s electronics capital and experience Shenzhen like a local hacker. Tour the famous Huaqiangbei electronics markets with people who live in the neighborhood, figure out what to eat and how to get around.

This time we have something new! Join us on a party bus to electronics and tools markets most foreigners could never find. We’ll have three solid days of market tours: Huaqiangbei, South China City, and Shajing. Check out the first camp here.


  • Optional: Tuesday 2 – early arrival dinner at Japanese Secret Location
  • Optional: Wednesday 3 – tour of Dongmen market & sign street, copy mall
  • Thursday 4 – How to survive Shenzhen, Huaqianbei tour, hot pot dinner
  • Friday 5 – tour of South China City market, BBQ dinner
  • Saturday 6 – tour of Yihua and Depu markets, Hacker shaokao and craft beer

That’s just an overview. See the full Hacker Camp Shenzhen schedule here. You can expect nightly dinners and parties all week. If you want to come really early, we’ll be in Tokyo November 20-25th for Tokyo Maker Faire.


Tickets for the camp cover bus rental, materials, meeting room, a translator, a set of PCBs, and 3 bottles of Tsing Tao (Ching Dao) per dinner. There’s only 20 tickets available and we expect they will sell out fast. Or maybe it’ll be a small intimate group. Who knows! We’re excited to see you there!

  • Student/Starving Artist ticket – $300
  • Normal ticket – $350
  • Supporter ticket – $450 (your name on the site and schedule of every future camp)

We also include allowance for Paypal fees, wire transfer fees, and currency conversion. Hacker Camp Shenzhen is a “no profit” event, meaning we’re lucky to break even.

Where to stay, visas, how to get there

City Inn is the recommended hotel, but be prepared for really bad internet and no WIFI. Check out the Hacker Camp mini-site and our Shenzhen survival guide. Be sure to get WeChat and join the Shenzhen Hacker group chat after you buy a ticket!

SIM card required

We’re traveling to places an hour or so north of Shenzhen, there are no taxis and nobody speaks English. Everyone must have a working SIM card with data. We can get them in China, or you can bring your own.

Can’t make this one?

Hacker Camp Shenzhen volume 4: “Pun TBD” will be in March or April after the Chinese New Year.

Tutorial : Control your launchpad using your voice

in MSP430 by DP | 1 comment


Antscran over at the 430h forum posted a how-to on using an Android phone and voice commands to control a MSP430G2553:

In this tutorial I will demonstrate a MSP430 voice control over Bluetooth, using a HC06 Bluetooth module.  I will be using an Android App I programmed which can be downloaded and installed, the C code for the MSP430 is also downloadable at the end of the tutorial.  So before we look at everything in further detail, the video below gives a demonstration of what the simple App and basic hardware set/up can do.  Note it was filmed with an older phone, so excuse the quality and dodgy camera angles.

Via 430h.

Check out the video after the break.

Continue reading →

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments

KHOS-2-3-4-5-6P 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.

Building and characterizing a DIY RF power sensor

in DIY by DP | 0 comments


Kerry Wong writes:

For the build, I followed LT’s reference design detailed in the datasheet. For the output filtering, I used a 2.2K/10pF output RC filter to limit the output bandwidth to around 3 MHz.
Since we are in the RF realm, board layout becomes much more critical than dealing with sub MHz circuits. But for the prototype, I used a piece of FR-4 PCB and routed a few islands for the power, input and output. This leaves us with a large contiguous ground plane which is critical in lowering ground inductance. The LC5534 chip is mounted on a trimmed adapter board, which is then glued onto the PCB’s ground plane. The wiring is kept as short as possible to minimize unwanted coupling. I used a BNC connector for the input. Since the maximum frequency LT5534 can handle is 3 GHz, a BNC connector should be sufficient. The BNC input is terminated right at the input. A RF rated surface-mount 47 Ohm resistor would have been ideal here but I used a nominal 50 Ohm (measured 47 Ohm) 1/16 W carbon film resistor instead as it’s the only kind I have on hand.

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DIRTY TUESDAY: Chinese Shipping Apocalypse

in, Shenzhen by Ian | 28 comments


A few months ago we started a private PCB website so our team can get cheap PCBs from our fab in China. Someone spilled the beans, and it hit Hack a Day, Hacker News, etc. We almost shut it down, but it was too much fun to hack and refine the process. Dirty Tuesday is a weekly post about our misadventures accidentally starting a PCB service. As a design shop with Seeed Studio doing fulfillment, we’ve never been on this side of the fence and want to share the terrifying experience.

Espeed Post is a logistics company in the Huaqiangbei electronics market in Shenzhen, China. They batch up shipments from tons of small shops, eBay sellers, etc, and negotiate bulk discounts with big carriers like DHL, Fedex, and UPS. They also do Hong Kong Airmail, 112RMB ($18) per kilo gets you anywhere in the world in 1-8weeks.

We are familiar with Espeed from the return address on packages from Seeed Studio and tons of other Shenzhen businesses. It was the immediate, easy choice when we needed to ship free PCBs for giveaways, or send prototypes and materials to team members around the world. Dirty PCB orders first went via free airmail only, then later by DHL, Fedex, UPS, Russian Airmail, Singapore Post, Netherlands Post, and a dozen other options that were sucked up via the Espeed API. More on the backend another week.

We have access to both China and Hong Kong versions of all major carriers. Prices are drastically different depending on destination, and there’s no consistency. Shenzhen and Hong Kong are essentially the same city, so the logistics companies truck stuff over the border into Hong Kong.

One thing is for sure, receiving a package handled by a logistics company confuses the hell out of some customers. It’s drastically different than your friendly Boys in Brown kicking a package onto a big brown truck:

  1. Shipment notification goes out
  2. Xiao Tang drops the shipment at Espeed’s office
  3. Espeed batches up a bunch of orders
  4. Orders are transferred to an agent and you get a tracking number
  5. The agent drives the packages to the shipper, possibly through Hong Kong Customs and into Hong Kong
  6. The package is transferred to DHL, UPS, or Fedex
  7. At this point, several days later, you actually start to see tracking info
  8. 18-24hours later your package is delivered

Espeed sells this service as 3-5 business day delivery. That is transit time only. It doesn’t include drop-off day, pickup day, or weekends. Sometimes delivery is amazingly fast, sometimes the window is stretched to the limit. It is, however, cheap. ~$16 for a 0.5kg UPS package to the US.

The 3-4 day window without a tracking update terrifies some people. Here’s slight mocking of some of the reoccurring themes:

  • It’s been 2 days with no updates. The order is lost. I order 100s of things from China and I always get my tracking number right away and immediate updates. Call your shipper now!
    • No, you chose dirt cheap DHL via Hong Kong and some guy is schlepping it there on a truck.
  • There’s no tracking update because you didn’t really ship my order. You just pretended because your board house messed up and you redid the order.
    • No, we’d just tell you and say sorry.
  • I paid the princely sum of $11 for express shipping and there’s still no updates after two days! It’s going to be late and I have a deadline for my (class/thesis/contest/project).
    • It will get there. The carrier provides 24hour delivery, it just takes a few days for logistics to get it to the carrier.

And on and on. There are days when we swear we’ll stop doing express shipping because it’s more work for us, and seems to make some customers manic too. We’ve even had a customer try to contact our logistics companies on their own.

Quality fade sets in. This is when a service starts out very strong, but creeps towards unusable. For us it was Espeed’s tracking API. Our system asks the API for any new tracking numbers every hour, and sends an email when available. This worked great for a while, but then got really intermittent and random. Some days it’s a crap shoot – you might get a tracking number, you might not. The tech is super responsive on QQ, but the problems never seems to get fixed permanently.

Remote area delivery is drag too. Some addresses, rightfully or not, are flagged as a remote areas. Parcels are held at Espeed until we pay an extra 249RMB ($50). Yes, the address may be in the middle of a huge city and nobody else hesitates to ship there, but the Chinese/Hong Kong DHL, Fedex, or UPS database says otherwise. We don’t control it, Espeed doesn’t control it, there’s absolutely nothing we can do. Espeed has an API to search by zipcode before taking the order, but it flags every postcode in the world as remote area and has yet to be fixed. Our current approach is to refund the shipping and send it Hong Kong Airmail. This is an area we absolutely must improve.

China has a ton of holidays. Long ones. Especially notorious is the National Day holiday. It’s ten days over the first week of October. That is exactly when the rest of the world is trying to get the latest hotness on store shelves for holiday shopping. Planes are full, trucks are full, customs has a huge backlog, then everyone just takes off for a week. Anyone doing business in China plans for this. We see more regular visitors, here to personally see things ship, than at any other time of year. Despite a giant red warning on the order page, we received 10+ emails asking why orders were not being processed. Probably the best thing to do, which Seeed has done in the past, is to not take orders at all during this period.

Then came the Chinese Shipping Apocalypse. The new President of China is moving swiftly to crack down on government corruption. Thousands of local, provincial, and national Chinese Governors have been fired or arrested for all manners of crime and corruption. In the midst of the holiday shipping glut, at the busiest land crossing between China and Hong Kong, officials found a van full of crystal methamphetamine and 2 tons of fake currency. 500 customs officials were fired for corruption, and now every package leaving China is inspected individually. Shipping times exploded from 3-5 days to 7-9 days or more. We had 10 orders, all on the same truck to Hong Kong, get stuck in customs for more than 10 days.  Lots and lots of anxious and angry customers, absolutely nothing we could do. Several logistics companies and our DHL contacts all confirmed that this is a nation wide problem, not just something effecting Espeed. In response we extended our delivery time estimate, though things seem to be calming down a bit now with the holiday over.

By dealing directly with DHL, rather than a logistics company, next-day and even same-day shipping are available. A DHL rep claims that we also get priority clearance through customs. It’s not nearly as cheap, something that’s passed on to customers, and we’ll have to write a new module to interact with their API. It’s also not easy. In the US and Europe you can signup for an account online. In China two suit clad reps visit several times and there’s an extensive application form and contract. Even then, it takes 10 days or longer to find out if the application is approved and there’s no guarantee. We’re currently waiting on approval, and hope to dump Espeed for express services and jump to faster, more reliable services straight from DHL.

We love being a design shop. We like to make things, and we let Seeed Studio do an amazing job handling the manufacturing and fulfillment part. This is our first taste of what it’s like to put things in boxes and deal with customer orders directly. DirtyPCBs was a unique chance to get a taste of that part of the business and hack it. It’s really gratifying to help people with projects, and the great feedback and comments keep it going. Every Tuesday we’ll share something about our experience with DirtyPCBs.





Posted in, Shenzhen | Tagged | 28 Comments

Digitally controlled 2.1 channel analog audio power amplifier

in open source by DP | 0 comments


Dilshan Jayakody  writes:

This article introduces high quality digitally controlled 2.1 channel analog audio power amplifier system. This project is mainly based on TDA7377 AF power amplifier and PIC18F452 8bit microcontroller. Basic features of this receiver are 2 × 6W + 20W audio output power, ±14dB bass and treble controls, fully configurable +35dB bass booster for sub-woofer and satellite speakers and loudness switch.
This system use commonly available electronic components and all the integrated circuits are in DIL packages. This amplifier consists with few UI elements such as 2 push buttons and 1 rotary encoder. All the menu navigation can perform through rotary encoder.

Video: AMBE exposed

in SDR, Videos by the machinegeek | 0 comments

AMBE is a voice compression algorithm employed in vocoder chips used by DVSI Inc., and is commonly used in Icom’s D-Star, Yaesu’s Fusion, APCO-25, DMR, Opensky and other digital formats on the amateur, commercial and public safety frequencies.

In this talk from last September’s TAPR/DCC conference in Austin, TX, Bruce Perens K6BP presented his views on the current state of the AMBE voice codec patent, and the potential this codec has in the amateur and radio experimenter community.

Visit HamRadioNow for details and links relating to the ongoing discussion of the AMBE patent situation.

We acknowledge HamRadioNow for their efforts in making this video available.

Darryl Smith via the contact form.

Posted in SDR, Videos | Tagged , , , | Leave a comment

Mini high voltage power supply

in power supply by DP | 0 comments


Victor8o5 posted detailed instructions of how to make this high voltage power supply. He writes:

WARNING: Before you start making anything please take a moment and read this:

  1. This circuit is intended to be used for educational and experimental purposes (electrostatic experiences, franklin bell experiment, plasma generation, gas ionization, electronic igniter, testing of insulating materials…) this circuit should not leave the lab or your house, and it shouldn’t be used to harm to anybody, human or animal.
  2. Do not attempt to replicate this circuit if you aren’t familiar with high voltages or intermediate electronics, high voltages are very dangerous.
  3. High voltages can disrupt electronic equipment, so don’t keep phones, pacemakers or other sensible electronic devices near the supply.
  4. I’m not responsible for the use given to this device and I’ve made all what it’s on my hands to include safety related information, and safety implementations to the circuit.

Follow the general security measures when dealing with high voltages, here you have a nice safety guide, please read it carefully before you continue.

Video: FlexRadio open API

in code, RF, SDR, Videos by the machinegeek | 1 comment

During the TAPR/ARRL Digital Communications Conference in Austin last September, Stephen Hicks N5AC gave this presentation on interfacing with FlexRadio using their open API.

Part II of this presentation was given by Graham Haddock KE9H, and discussed the FlexRadio wavefrom API. It is available from HamRadioNow.

FlexRadio produces a series of high-end SDR’s, with the lowest price rig being the FLEX-1500 which geared toward the amateur radio community. It retails for about $700 an covers 490 kHz to 54 MHz.

Darryl Smith via the contact form.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 77 comments


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 →

Posted in Free PCBs | Tagged | 77 Comments

App note: Analog-to-Digital conversion using a PIC16C5X/PIC16F5X

in app notes by DP | 0 comments


PIC16C5X and PIC16F5X microcontroller families are low cost off-the-shelf solution for common analog measurements like voltage and current. Here’s an app note (PDF) from Microchip on how to do A/D conversion on these chips.

The converter requires only five external components and is software and hardware configurable for conversion resolutions from six bits up to ten bits, and conversion times of 250 us or longer. The method is usable for both voltage and current conversion and uses a software calibration technique that compensates for time and temperature drift, as well as component errors.

App note: Bit-Banging the SDI and SQI Modes of Microchip’s 23XX512/23XX1024 Serial SRAMs

in app notes by DP | 0 comments


Dual Mode(SDI) and Quad Mode(SQI) Serial interface are not common peripherals on many MCU today, Microchip’s app note (PDF) provides an alternative way to communicate with these SRAMs using existing GPIOs pins in bit-bang.

This application note explains in detail the recommended usage of the SDI and SQI modes of operation of the Microchip 23XX512/23XX1024 Serial SRAM devices, as well as the possibilities to configure the device for the above alternative modes of operation.

DANGERCORE: PHP and Javascript developers needed

in site by Ian | 0 comments


Good at PHP and/or Javascript and looking for part time projects? We need to hire a couple PHP and Javascript programmers to work with me on several large projects long term. Some of what we do will be open source immediately, some will need to be secured against hacks a bit first, some will be released as modules without our logos and templates.

On the PHP side we’re working with Codeigniter/Bonfire, on JS we’re all over JQuery. 10-20 hours a week, or more. Team players, able to use GIT. I’ve architected the majority of the system, but need help bringing it to life. We’ll live blog the development process and put the development live an on the internet as soon as its locked down enough to be deployed at

Please hit us up by the contact forum. Describe your strengths, link to any projects you’ve worked on, and include an hourly rate.

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Review: Kano DIY computer kit

in dev boards, DIY, kit biz, R-Pi by the machinegeek | 5 comments

Steve Schuler has posted this review of the Kano DIY computer kit on Science 2.0.

I’ve lost count of how many computers I’ve built over the years, but I think it is safe to say that the Kano Computer was the easiest build ever. So simple a child could do it. Kano founders, Yonatan Raz-Fridman, Alex Klein, and Saul Klein, wanted to figure out what the next generation’s computer would be like, so they asked Micah, Saul’s seven-year-old son. Micah advised that he wanted to build the computer himself but it “had to be as simple and fun as Lego,” and “no one teaches me how to do it.”

The Kano is “a computer and coding kit, designed for all ages, all over the world.” It will get “you programming in minutes, with simple blocks that create real code.” It’s designed to “to give young people – and the young at heart – a simple, fun way to make and play with technology, and take control of the world around them.”

In reality what is the Kano? According to the Kano website the kit includes a Raspberry Pi along with a keyboard, SD card with the Kano OS, speaker, case, power supply, cables, WiFi USB adapter and written materials designed to help those totally new to the tech scene how to assemble and program a R-Pi setup. It retails for $149.99 shipping included.

Via the contact form.

Posted in dev boards, DIY, kit biz, R-Pi | Tagged , | 5 Comments

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 2 comments


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:

Continue reading →

Posted in Free PCBs | Tagged | 2 Comments