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#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, May 23rd, 2017 in Free PCBs by DP | No Comments

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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.

8-bit assembler compiler project

Posted on Monday, May 22nd, 2017 in open source, software by DP | 1 Comment

8-bit assembler compiler

Dilshan Jayakody writes, “8-bit Assembler compiler is NASM compatible assembler compiler to generate binaries for 8-bit x86 like CPUs. The binaries produced with this compiler can execute on Marco Schweighauser’s 8-bit virtual Javascript CPU.
This native compiler can build using Lazarus / FPC. During the implementation we build and test this compiler successfully on Linux and Windows operating systems.”

More details at Dilshan Jayakody’s blog.

Cross section and analysis of a SMT inductor

Posted on Monday, May 22nd, 2017 in components, techniques by DP | No Comments

A look at the cross section of a surface mount inductor from Electronupdate.

App note: Interfacing to analog switches: Driving the control input of an analog switch with 1.8 V or lower − Is it safe?

Posted on Sunday, May 21st, 2017 in app notes by DP | No Comments

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ON Semiconductor’s analog switches let you drive with an input control voltage lower than Vcc. Link here (PDF)

Analog switches are everywhere today. Due to their small size and low current consumption, they are popular in portable devices where they are effective in a variety of subsystems including audio and data communications, port connections, and even test. They can be used to facilitate signal routing, allow multiple data types to share an interface connector, or permit temporary access to internal processors during manufacturing. Analog switches are often used to give portable system designers a convenient method of increasing their features or accessibility without duplicating any circuitry. Understanding the key specifications and tradeoffs can make the difference between a temporary fix and a truly optimized solution.

Free PCB Sunday: Pick your PCB

Posted on Sunday, May 21st, 2017 in Free PCBs by DP | 23 Comments

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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: Consideration of self-pollution reduction for electronic systems

Posted on Sunday, May 21st, 2017 in app notes by DP | No Comments

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App note from ON Semiconductors discussing how locally generated EMI affects its own system and how to prevent it. Link here (PDF)

This application note will address the problem of Electro Magnetic Interference (EMI) self pollution in which one part of an electrical systems such as cell phones and consumer electrical products emit radiation that interferes with the operation of other parts of the system.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, May 19th, 2017 in Free PCBs by DP | No Comments

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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:

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A 2-channel receiver that can save your old Motorola TX

Posted on Thursday, May 18th, 2017 in open source by DP | No Comments

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Boris Landoni writes about a new open source project 2-channel receiver that can save your old Motorola TX:

A 433,92 MHz Receiver that can be paired with a maximum of 10 Motorola TX each with relay outputs that can be set both in monostable or bistable mode.

Although we have had high security encoding for several years, based for instance on rolling-codes, a lot of remote controls and especially those installed long time ago in houses and other places for opening gates, are based on fixed and relatively simple encoding like the MM53200 of former National Semiconductor and the Motorola MC14502x; the latter had two new elements at the time of its introduction, that were the high (for the times) number of combinations allowed (19,683) and the three-state encoding (each encoding input of the encoder and of the decoder would allow three logic levels and required special three-state dip-switches).

More details at open-electronics.org.

TB timer – Timed camera cable release

Posted on Wednesday, May 17th, 2017 in Arduino, DIY by DP | No Comments

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Steve Smith has published a new build:

It’s taken some research but I have built a prototype with my trusty ARDX Arduino Uno kit
Currently, the device changes mode with a press of the mode button which will later be incorporated in a suitable rotary encoder. I modified the prototype’s rotary encoder to remove the detents and therefore, have continuous motion rather than be stepped. When stepped, the value hops by two at a time. The ‘B’ and ‘T’ modes both operate as expected and at the moment, the rotary encoder changes a value in ‘TB’ mode and is displayed on the OLED display. the outputs are opto-isolated so will appear as switches to the camera. Although I’ll be using the cable release with a Canon DSLR, it should be very easy to make it work with other DSLR makes.

Project info at projectavr.com.

MCUXpresso IDE tutorial series

Posted on Wednesday, May 17th, 2017 in ARM, tutorials by DP | No Comments

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Erich Styger has made a series of tutorial blog posts on using the new NXP MCUXpresso IDE.

Published so far are:

  • MCUXpresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers
  • MCUXpresso IDE: S-Record, Intel Hex and Binary Files
  • MCUXpresso IDE: Adding the Eclipse Marketplace Client
  • MCUXpresso IDE: Importing Kinetis Design Studio Projects
  • MCUXpresso IDE: Installing Processor Expert into Eclipse Neon
  • MCUXpresso IDE: Terminate and Disconnect a Debug Session
  • MCUXpresso IDE: Blinky the NXP LPC800-DIP Board

More details at mcuoneclipse.com.

RX/TX sequencer

Posted on Wednesday, May 17th, 2017 in digital radio data, PIC by DP | No Comments

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Lukas Fässler has designed and built an RX/TX sequencer based on a PIC16F18325,  that is available on github:

Much like the beacon keyer presented here earlier, this RX/TX sequencer is a simple but useful little device. Its typical use is in ham radio applications when a separate power amplifier (PA) and/or a sensitive low-noise pre-amplifier (LNA) is used. Care has then to be take to safely transition between RX and TX states – and that’s where this sequencer comes in.

Project info at Soldernerd homepage.

Check out the video after the break. (more…)

Philips MR16 12V 2017 LED teardown

Posted on Wednesday, May 17th, 2017 in Teardowns by DP | No Comments

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Teardown of a 500lm MR16 12V LED light bulb from Electronupdate.

Check out the video after the break. (more…)

Bus Pirate PCB build

Posted on Tuesday, May 16th, 2017 in builds, Bus Pirate by DP | No Comments

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Ben Kazemi shares his latest build a Bus Pirate v3.6a PCB.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

My latest build – i have to say the yellow soldermask is prettier than it looks on the photos, i also like to think i earnt something special for having ENIG pads :p

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

Deepace KC901V 6.8GHz handheld network analyzer review, teardown and experiments

Posted on Tuesday, May 16th, 2017 in Teardowns by DP | No Comments

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Teardown and analysis of Deepace KC901V 6.8GHz handheld network analyzer from the The Signal Path:

In this episode Shahriar reviews the Deepace KC901V 6.8GHz handheld network analyzer. This battery-powered instrument is an RF multi-instrument integrating VNA, spectrum analyzer, field strength meter, and a low-frequency signal generator. It can also perform signal port vector measurement and 2-ports simple vector network analyzing (S11, S21).

More details at The Signal Path homepage.

Check out the video after the break. (more…)

Pulsecounting and deepsleep based IoT water meter

Posted on Monday, May 15th, 2017 in hacks, wireless by DP | No Comments

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Tisham Dhar has written an article detailing his pulsecounting and deepsleep based IoT water meter project:

I admit to being a tiny bit obsessed with monitoring utility bills and gathering data on my usage patterns blow-by-blow. The energy monitoring has reduced my electricity bills, so I wanted to have a go at the water usage. Granted a lot of the water bill is fixed supply costs and sewerage charges which I can’t do much about.
A while ago I made some pulse counting breakouts with the DS1682+ RTC. I have finally got a chance to put them to good use interfacing with my mechanical water meter. The water meter has a spinning permanent magnet and in principle this can trigger a reed switch and generate pulses for accumulation by the RTC.

More details at Tisham Dhar’s blog.

A DC motor controller with control LEDs

Posted on Monday, May 15th, 2017 in open source by DP | 1 Comment

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Boris Landoni writes about a new open source project a DC motor controller with control LEDs:

It can be controlled through logic levels to set the speed and the direction of the rotation of CC brushed motors and stepper motors; outputs have LEDs indicating the rotation direction.

The circuit board we are presenting this time is based on the dual-bridge driver L298N, in a traditionally mounted version in a Multiwatt container with 15 staggered pins; it has two terminal blocks for attaching to DC motors or the coils of a bipolar stepper motor and a terminal block for powering logics and motors. Each of the two output channels of the circuit can provide a maximum current of 2 A, which is enough to drive two 2 A direct current motors or a bipolar stepper motor absorbing 2 A per phase.

More info at Open-electronics.org.

Free PCB Sunday: Pick your PCB

Posted on Sunday, May 14th, 2017 in Free PCBs by DP | 23 Comments

BP-600x373

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: Active capacitor discharge circuit considerations for FPGAs

Posted on Sunday, May 14th, 2017 in app notes by DP | No Comments

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Power down sequencing and discharging on FPGAs app note from Diodes Incorporated. Link here (PDF)

FPGA’s need the different power rails to be powered up and down in a defined sequence. For power down, each sequenced rail needs to be fully off before the next rail is turned off. With large high speed and high functionality FPGA’s, the power rails have large bulk capacitors to be discharged quickly and safely within a total time of 100ms and up to 10 rails each to be discharged within 10ms.

This application note shows a methodology and considerations for safe open ended shutdown to be controlled by a power sequencing circuit and using correctly chosen MOSFET to discharge the capacitor bank.

App note: Power supply rejection for low-jitter clocks

Posted on Sunday, May 14th, 2017 in app notes by DP | 1 Comment

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Method of rejecting noises from power supply, an app note from Silicon Labs. Link here (PDF)

Hardware designers are routinely challenged to increase functional density while shrinking the overall PCB footprint of each new design. One significant challenge is minimizing clock jitter through careful board design while meeting the design’s functional and space requirements. Since jitter is a measure of signal fidelity, it requires an understanding of diverse analog concepts, such as transmission line theory, interference, bandwidth, and noise, in order to manage their impact on performance. Among these, density impacts sensitivity to external noise and interference the most. Since noise and interference are everywhere and since multiple components share a common power supply, the power supply is a direct path for noise and interference to impact the jitter performance of each device. Therefore, achieving the lowest clocking jitter requires careful management of the power supply. Sensitivity to power supply is commonly referred to as power supply ripple rejection or power supply rejection ratio (PSRR). For jitter, ripple rejection is more appropriate.

Adjustable constant current source

Posted on Friday, May 12th, 2017 in tools by DP | 5 Comments

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Dilshan Jayakody has published a new build:

The current source introduced in this article is capable to handle current up to 6A with maximum input voltage of 50V. This is an operational amplifier based adjustable current source and it uses LM358 in a general voltage follower configuration. To handle large currents we use four 0.1Ω 20W resistors as “load resistor”, and those load resistors are drive through pair of 55N06 N-channel MOSFET transistors.
The power supply unit of this project is build around 9V x 2 (2A) step-down transformer and it is design to get regulated 12V DC voltage. In our design this 12V power source is used to drive LM358 Op-Amp and 12V cooling fan.

More details at Dilshan Jayakody’s blog. Project files are available at elect.wikispaces.com.

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Recent Comments

  • Alan: "8-bit x86 like CPU" - isn't that an 8080, or Z80?
  • Geoff: Is it still Sunday somewhere? If so, yes please.
  • hli: Sunday++
  • Mikee: Yes!
  • Clay: Free PCBs!