#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments

BP-600x373

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.

HOW TO: Start a Chinese Company

foreign-invest-cert

While Shenzhen is becoming “Hollywood for Makers”, and not always in a good way, there don’t seem to be a lot of foreign open hardware/maker/start-up/accelerated/innovated/incubated people starting Chinese companies. As far as we know, we are the first foreign owned open hardware centric Chinese company in Shenzhen. With everything going on here, we definitely wont be the last.

There are three reasons foreigners start a Chinese company: to sell to China’s domestic market, to get legal residency, and to work with small suppliers who can’t accept foreign currency. We are only interested in the latter.

Working with a controlled currency

rmb-note

Chinese RMB is a controlled currency. Money only goes in and out of China for certain purposes, in allowed amounts, with the proper license. Most small Chinese suppliers don’t have an import/export license (and dodge taxes) so they can’t convert payments made in a foreign currency.

compression-molding

That’s why it is almost impossible for you, from abroad, to work with the small, flexible, inexpensive Chinese suppliers we have access to. If you really want to make small scale supply chain mash-ups, say 100 traffic-themed adult novelties, then tiny suppliers are crucial and they must be paid in RMB.

Continue reading →

Maker’s rule, the feature packed PCB multi-tool

in tools by DP | 0 comments

pics
Rohit Gupta made a more refined version of his tinker rule:

My initial scale was big and not handy, So, this one should be small and compact and must not miss a single feature from its ancestor. This one has :

  • 0.1 inch grid to quickly prototype/resolve parts for perf-boarding or part creation
  • A collection of footprints and holes to quickly compare parts
  • A small pad with a sand paper to rust off those berg strips/resistor ends that just wont solder located ergonomically at the end to allow easy motion
  • A key chain form factor
  • A LED Tester
  • A continuity tester compatible with most common 4.5mm banana plug type probes and alternatively alligator clips too
  • A reference section for common equations,scales and track widths.
  • 0.1 inch scale at right angles
  • 1 mm resolution scale at right angles

Project info at Rohit Gupta’s blog.

Via the contact form.

 

 

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Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 50 comments

IRToy

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 | 50 Comments

App note: Projection with LED light sources

in app notes by DP | 0 comments

an_osram_projection_led

LEDs are now mostly used in light projection systems due to their low power requirements, long life and robustness. Here’s an app note from OSRAM for proper integrations on these projection LEDs. Link here (PDF)

This application note provides insights into the use of LED light sources for projection applications. An overview of LED projection systems and their benefits is presented, along with a summary of OSRAM Opto Semiconductors LEDs suitable for these applications. Finally, fundamental design issues related to the use of LEDs in projection modules are addressed.

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App note: Potting protection for outdoor LED video walls and signs

in app notes by DP | 3 comments

an_osram_potting_leds

LED signs and large LED video panels are always subjected to harsh environment resulting to corrosion to their pcb mountings, here’s an app note from OSRAM about potting these LED panels for protection. Link here (PDF)

This note provides basic information about the potting of flat SMT LEDs in video wall and signage applications. Thereby details on material in use, examples of suitable equipment and the process are presented and described. Additionally, the note gives a short intro into video walls with a typical setup, varying LED type system effects and general challenges. Finally, the results of selected environmental tests are presented, to demonstrate their impact and the aptitude of potting protection method.

Posted in app notes | Tagged , , | 3 Comments

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 0 comments

BP

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 →

Simple small QRO for HF

in DIY by DP | 1 comment

IMG_8931-600

Marko Pavlin has been working on a HF amplifier project:

I followed the ARRL Homberw challenge 50 watt aplifier entry. It is low cost, simple HF linear amplifier designed and built by the author as an entry in the ARRL’s 2009 Homebrew Challenge contest. The requirements of the amplifier were: 40 meter band 50 watt output amplifier intended for use with a QRP transmitter as driver (less than 5W), constructed at a total material cost of not over $125.00.
I redesigned author original design an put it on the double sided PCB with additional output banpass filters. I started with first prototype. It worked quite well for short periods. Main disadvantage was lack of heat sink. Then I soldered second prototype with proper transistor cooling. I also wound correct transformer using binocular ferrite cores
Next step was designing PCB. I started with the schematic diagram based on original project

Project info at Mare & Gal Electronics homepage.

 

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Teardown, repair & calibration of a Valhalla 2701C Programmable Precision DC voltage standard

in Teardowns by DP | 0 comments

A teardown and repair of a Valhalla 2701C Programmable Precision DC voltage standard from The Signal Path:

In this episode Shahriar examines a faulty Valhalla 2701C Programmable Precision DC Reference instrument. Valhalla Scientific’s 2701C Programmable Precision DC Voltage Calibrator delivers ultra-precision, ultra-stable DC voltage from 100 nanovolts to 1200 volts. This unit does not have a working front-panel LCD screen. Luckily, that problem is resolved very quickly.
The internal build and operation of the unit is briefly examined and the instrument is calibrated using a Keithley DMM7510 7.5-digit multimeter. It is possible to upgrade this unit to a more stable and accurate reference voltage generator or to add the reference current capability to it.

More info at The Signal Path homepage.

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Bus Pirate v3.8 free PCB build

in builds by DP | 0 comments

buspirate

David built a free Bus Pirate v3.8 PCB.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

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.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Via the contact form.

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 1 comment

BP-600x373

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.

Posted in Free PCBs | Tagged | 1 Comment

ESP8266 mains energy monitor

in DIY, wireless by DP | 0 comments

pcb-in-case

A ESP8266 mains energy monitor project by Brian Dorey:

 As the new solar logger did not have this functionality we decided to design a new data-logger that would measure not only the mains current usage but also keep track of the electric meter and gas meter so we can easily see how much energy we are using in the house.
The new mains energy monitor was designed to be a standalone box that would be powered from the mains and have sensors for the mains current, electric meter and gas meter. As we didn’t want to run any more wires around the house we also decided to make it wireless connecting to our network over Wi-Fi.

Project info at Brian Dorey’s blog.

MIDI to USB adapter with Teensy LC

in hacks by DP | 0 comments

circuit

Joonas has written up documentation on his MIDI to USB adapter with Teensy LC:

Thankfully, I had a MIDI connector and a high-speed optocoupler at hand, and with these I could implement a MIDI in rather easily. After some investigation with Arduino Uno, it seemed quite simple to receive the serial MIDI bytes and dump them over Arduino serial (I’ll write another post about this later).
However, Arduino cannot become a USB MIDI device very easily, so here comes the really nice part: Teensy LC can, and the Teensyduino add-on included a working USB MIDI and also serial MIDI libraries!

More info at Code and Life site.

Via the contact form.

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App note: PointLED® – It’s nice to be different

in app notes by DP | 0 comments

an_osram_point_led

New SMD LED design from OSRAM ideal for mounting on PCB holes for illumination. Link here (PDF)

This application note provides insight into the universally deployable and flexibly mountable light source of the PointLED® product family. A fundamental overview of the LED construction as well as the optical and electrical characteristics and performance of the LED are presented.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 53 comments

IRToy

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 | 53 Comments

App note: How to handle a reed switch

in app notes by DP | 3 comments

an_hsi_HSI_Sensing_-_How_to_Handle_a_Reed_Switch_v100512

Proper handling of reed switches to prolong operation and or storage, an application note from HSI sensing. Link here (PDF)

Reed switches consist of two or three metal reed contacts (blades) that are hermetically sealed inside a glass tube. This seal, while strong, may be damaged if proper handling is not used. HSI Sensing has years of experience handling reed switches and have identified several best practices.

More ARM1 processor reverse engineering: the priority encoder

in reversed by DP | 0 comments

full-encoder-labeled

In a previous post, Ken Shirriff reverse engineered the silicon in the ARM1 processor, this time he reverse-engineer the priority encoder in the ARM1 processor:

In this article, I reverse-engineer the priority encoder in the ARM1 processor. By examining the chip layout provided by the Visual ARM1 project, I have determined how this circuit works and created a schematic.
The ARM1 chip is the ancestor of the extremely popular ARM processors used in most smart phones. The ARM1 is a good choice for reverse engineering since it was designed in 1985 and its simple RISC silicon circuits are easier to understand than modern processors. This article jumps into the chip details; if you want an overview of the ARM1 internals, start with my first article on reverse engineering the ARM1.

More details at Ken Shirriff’s blog.