Free PCB Sunday: Pick your PCB

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. Some of these boards originate from commercial hardware tests, such as a recent RFID reader designed to track VIP access tokens across a list of sweepstakes casinos and regional arcades, while others are just simple breakout boards for new sensors. 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: Enhancing cellphone battery performance during GSM pulses through the use of a parallel supercapacitor

an_avx_EnhancingCellphoneBatteryPerformance

Low ESR and ESL supercapacitor paralleled to cellphone batteries can react more quickly to the demanding power required by GSM pulses. A great appnote read from AVX, link here (PDF)

With the constant addition of data-intensive features and functionality such as continuous GPS tracking, high-definition media streaming, and the real-time server connections required by mobile online slots, battery life and reliability are becoming increasingly vital to those who rely on their smartphones. The transmission signal requires quick pulses of current from the battery, potentially causing the instantaneous voltage of the battery to drop below the phone’s minimum voltage of operation. This may cause the power to the battery to be temporarily interrupted. A series of tests were performed on multiple battery chemistries to determine the beneficial effect of placing an AVX supercapacitor in parallel with the battery, to improve the life of the battery as well as the quality of power provided from it.

App note: QuickBoot method for FPGA design remote update

appps

A QuickBoot method for FPGA design remote update application note (PDF!) from Xilinx:

This application note presents detailed descriptions of the QuickBoot method that are important for evaluating the QuickBoot solution and debugging implementation problems. Demonstration implementations of the QuickBoot method are provided for the KC705 evaluation board using the serial peripheral interface (SPI) flash or byte-wide peripheral interface (BPI) flash. See KC705 Board Demonstrations, page 33 to run the QuickBoot demonstrations on the KC705 evaluation board.

App note: High voltage adjustable power supplies

 

app2

TI application note (PDF!) on high voltage adjustable power supplies:

An improved approach is shown in Figure 2. Here an LM329B 6.9V zener reference has been stacked in series
with the LM317’s internal reference. This both improves temperature stability, since the LM329B has a guaranteed TC of ±20 ppm/˚C, and improves regulation, because more loop gain is available from the LM317.
These techniques can be extended for higher output voltages and/or currents by either using better high voltage transistors or cascoding or paralleling (with appropriate emitter ballasting resistors) several transistors. The output short circuit current, determined by R3, must be within Q2’s safe area of operation so that secondary breakdown cannot occur.

Free PCB coupon via Facebook to 2 random commenters

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 “Free PCB coupon via Facebook to 2 random commenters”

Arduino MPPT solar charger shield

20160119_projekte_028

Lukas Fässler made an MPPT solar charger project and wrote a post on his blog detailing its assembly:

The basic idea behind an MPPT solar charger is simple. A solar panel has a certain voltage (in the region of 17 to 18 volts for a 12 volts pannel, somwhat dependent on temperature) at which it provides most power. So as long as the battery needs charging, you want to pull just as much current to reach this voltage. But once the battery is full you need to avoid overcharging the battery. So you want to maintain a maximum voltage for your battery (somewhere around 13.8 volts for a 12 volt lead acid battery) and no longer care about the pannel’s voltage.

Project info at Soldernerd site.

ESP8266 – Wireless weather station with data logging to Excel

Wireless-Weather-Station-with-Data-Logging-to-Excel-thumb-600

Rui Santos writes, “In this project we are going to establish a wireless communication between two ESPs and send data from three sensors to an Excel spreadsheet. This tutorial shows a wireless weather station with data logging that you can implement in your home.”

Project info at Random Nerd Tutorials site.

Datalogging Accelerometer Data To An SDCard

msp430_datalogger_sdcard

MindForge built a datalogger project which logs accelerometer values to an SDCard:

This project started as an EMG datalogger to study my dad’s Parkinson’s disease, but after some testing I determined wearing electrodes wasn’t practical for the long term datalogging that I wanted to do, the data ended up very noisy due to RF interference and shoddy electrode to skin connections.
I moved away from the EMG idea and began working on a low-cost low-power consumption accelerometer datalogger instead.

Via 43oh.

#FreePCB via Twitter to 2 random RTs

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 “HOW TO: Start a Chinese Company”

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

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.

 

 

Free PCB Sunday: Pick your PCB

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 “Free PCB Sunday: Pick your PCB”

App note: Projection with LED light sources

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.

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

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.

Free PCB coupon via Facebook to 2 random commenters

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 “Free PCB coupon via Facebook to 2 random commenters”

Simple small QRO for HF

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.

 

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

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.

Bus Pirate v3.8 free PCB build

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

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.