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Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, April 14th, 2017 in Free PCBs by DP | No 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:

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MPPT solar charger rev c

Posted on Friday, April 14th, 2017 in DIY by DP | No Comments

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Lukas Fässler from Soldernerd has been working on revised version of his MPPT Solar charger project:

Over the last few weeks I have been quite busy with my MPPT Solar Charger project. I’ve built up a first board and started writing firmware for it. Since the last version was not too different in terms of hardware I was able to re-use most of that code. But I hadn’t even touched on the whole USB stuff back then so there was still a lot of work to do. While the project is still far from being complete I am happy to say that I’ve made quite some progress. Most importantly, the new design seems to work well and so far I haven’t found any mistakes in the board layout. But let’s go through this step by step.

More details at Soldernerd homepage.

Tutorial: Using Eclipse with NXP MCUXpresso SDK v2 and processor expert

Posted on Thursday, April 13th, 2017 in ARM, tutorials by DP | No Comments

sdkv2-project-with-processor-expert

Erich Styger from MCU on Eclipse writes:

To me, software and tools are by far more important than the microcontroller. Because the silicon is a ‘one time kind of thing’, where the software has to be maintained and working over a longer time. And at least my software usually needs to be ported to a new device, so portability and available software and tools are critical to me.

The combination of MCUXpresso SDK (formerly Kinetis SDK) and Processor Expert is unfortunately not supported by NXP. But I have found a way to get them work together in a nice way, and this article is about making that combination possible :-).

More details at MCU on Eclipse homepage.

Bridge monitoring system using wireless sensor network

Posted on Thursday, April 13th, 2017 in sensors, wireless by DP | 1 Comment

pics-LabVIEW

Zx Lee and his friends built the bridge monitoring system using wireless sensor network, that is available at github:

Recently, I completed a mini project together with two of my friends. So I am going to take this opportunity to share the project that we have made, we named it the Bridge Monitoring System (BMS) using Wireless Sensor Network (WSN). We are required to design an embedded system that is related with disaster management, either mitigation, preparedness, response or rehabilitation. To give you a high level overview of this project, basically we created three sensor nodes that acquire sensor measurement and transmit to central hub through wireless network. The sensor network works in a many-to-one fashion and data processing is done on the central hub. All the sensor measurement from each node is also displayed on the Host PC for user interface. Therefore, in this article, I am going to walk through some details of the project and how it works.

Project info at Zx Lee’s blog.

How Scotty made his own iPhone in China

Posted on Thursday, April 13th, 2017 in Shenzhen by Ian | No Comments

Over the past two months we’ve been super excited to follow Scotty’s adventure recycling/refurbishing an iPhone 6S in the used cell phone market just south of Huaqiangbei, Shenzhen, China. Scotty finds all the bits and pieces from various sellers and then follows the iFixit instructions, backwards, to build his own recycled franken-phone.

Despite living in the market and running six hacker camps, it was still not clear to us exactly what goes on in the used cell phone markets. This video blows that open and exposes the brisk trade in recycled iPhone parts here in Shenzhen.

Along with This is Not Rocket Science, Scotty also took us on a three day phone recycling expedition earlier this month. Watch his channel for more videos and clips soon!

Teardown of a TDA7375 audio amplifier IC

Posted on Wednesday, April 12th, 2017 in Teardowns by DP | No Comments

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A teardown of a TDA7375 audio amplifier IC from Electronupdate:

The TDA7375 audio power amplifier.
Another example of a long-lived integrated circuit.  1st introduced in 1998… looks like it’s still being made.

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

Magic Mote MSP430G2553 wireless sensor node with NRF24L01+ module

Posted on Wednesday, April 12th, 2017 in MSP430, wireless by DP | No Comments

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Tom from Magic Smoke writes:

This is my first time designing a PCB for MSP430. I really like the NRF24L01+ booster pack but I would like something smaller to use for remote temperature sensors. With that in mind I’ve designed a 24.5 x 50 mm PCB (2 on a 5×5 cm prototype) featuring MSP430G2553 and an adapter for a 8-pin NRF24L01+ module using essentially the same pinout, with the intention of using the Spirilis library. There’s a jack socket to connect a 1-wire sensor (e.g. DS18B20), a 4-pin header to connect a temperature/humidity sensor (SHT22 or similar), a programming header that gives serial access, and 3 other general purpose I/O pins.

More details at Magic Smoke blog.

Bus Pirate v3.8 free PCB build

Posted on Monday, April 10th, 2017 in builds by DP | No Comments

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Zak 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.

Cheap UV EPROM eraser teardown and spectrum analysis

Posted on Monday, April 10th, 2017 in Teardowns by DP | No Comments

 

pics-EPROMEraser-600

Kerry Wong did a teardown of a cheap UV EPROM eraser and measured the spectrum of the UV tube using a monochromator:

Till recently, I have been using custom circuitry whenever I needed to backup some firmware. But the process was rather tedious as for each kind of EPROM or EEPROM I needed to study the protocol and timing requirements and then come up with the required circuitry on a breadboard. And wiring can easily become an issue with a high pin-count chip. So I finally got myself a proper EPROM programmer (it’s a TL866A) along with a $15 generic UV EPROM eraser so I could program EPROM/EEPROM’s quickly. While it was fun to build a programmer circuit each time, I think the effort can be put into something more useful.

More details at Kerry Wong’s blog.

Check out the video after the break.

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Free PCB Sunday: Pick your PCB

Posted on Sunday, April 9th, 2017 in Free PCBs by DP | 28 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: Current sensing power MOSFETs

Posted on Sunday, April 9th, 2017 in app notes by DP | 1 Comment

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SENSEFET App note from ON Semiconductors incorporate a current sense inside a power MOSFET, these devices are straight forward calculating for sense resistance and voltage but have trade-offs for smaller current sensing. Link here (PDF)

Current sensing power MOSFETs provide a highly effective way of measuring load current in power conditioning circuits. Conceptually simple in nature, these devices split load current into power and sense components, and thereby allow signal level resistors to be used for sampling. Since this technique results in higher efficiency and lower costs than competing alternatives, understanding how to use SENSEFET product is an important design issue.

Getting accustomed to these devices is relatively, but not completely, straightforward. They are conceptually simple, but have their own unique set of characteristics and subtle properties. The following discussion examines both, and starts with a description of how SENSEFET devices work.

App note: Load switches: What are they, why do you need them and how do you choose the right one?

Posted on Sunday, April 9th, 2017 in app notes by DP | No Comments

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Application report from Texas Instruments on load switches to simplify power supply design. Link here (PDF)

Integrated load switches are electronic relays that can be used to turn on and turn off power supply rails in systems. Load switches offer many other benefits to the system and can include protection features that are often difficult to implement with discrete components. There are many different applications where load switches can be used including, but not limited to:

-Power Distribution
-Power Sequencing and Power State Transition
-Reduced Leakage Current in Standby Mode
-Inrush Current Control
-Controlled Power down

This application note will provide the fundamental basics of what load switches are, when they should be used, and how they can be implemented in a system.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, April 7th, 2017 in Free PCBs by DP | 5 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:

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DivMMC Programmer

Posted on Thursday, April 6th, 2017 in Arduino by DP | No Comments

 

DivMMC Programmer

Dave Curran blogged about his Arduino based programmer for the DivMMC future:

With the labels on, it may make more sense. This is a programmer and tester.
And that is what it programs and tests, the new DivMMC Future from The Future Was 8 Bit. With lots of orders for this coming it, programming each one individually takes a long time, so this will automate this process and program 4 units in parallel. Not directly, but via a number of remote controlled ZX Spectrums.

More details at Tynemouth Software blog.

Making the Electronics for a 24GHz doppler motion sensor

Posted on Tuesday, April 4th, 2017 in sensors by DP | No Comments

cdm324_assembled_quarter_m

Limpkin has a nice write-up on his tiny CDM324 Doppler speed sensor:

You may recall the article I wrote a couple of years ago about a nearly identical Doppler sensor, the HB100.
While the HB100 is using a 10.525GHz frequency, this new module uses 24.125GHz! This has the main advantage of being compatible with European regulations (ETSI #300 400) and having good penetration in dry materials. Moreover, as the main frequency is higher the patch antennas are smaller, hence the tiny 25x25x6mm module.
This motion sensor can easily be purchased on eBay under the name CDM324. Oddly enough, looking for “cdm324” on your favorite search engine won’t bring any interesting results.
I therefore spent several hours tracing the origins of this tiny sensor. I finally arrived to the conclusion that it likely is a clone of the InnoSenT IPM 165, which is itself very similar to the AP96 from Agilsense.

Project info at Limpkin’s blog and the  GitHub repository here.  It’s also up on Tindie.

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

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, April 4th, 2017 in Free PCBs by DP | 1 Comment

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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.

Dumb thermometer gets digital output

Posted on Monday, April 3rd, 2017 in how-to by DP | No Comments

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Saulius has finished a new project article, a dumb thermometer gets digital output:

Some time ago I purchased 4 channel thermometer. Soon after tried few optical character recognition (OCR) techniques on 7 segment symbols including pytesseract, they worked but I was not happy with results. Few days ago pyimagesearch published article detailing his approach. So I pushed it a bit forward and made solution more robust. Also added possibility to analyze video instead of single frame.

Full source code available at Kurokesu blog.

Via the contact form.

Homebrew PiHPSDR

Posted on Monday, April 3rd, 2017 in DIY, R-Pi by DP | No Comments

pihpsdr_rp

g4fre built his own PIHPSDR, that is available at github:

Having seen the Apache-labs version of the PIHPSDR I wanted to customise it to fill my needs, so I needed to build my own
All the needed information , with the software, is at John Melton’s github site github.com/g0orx/pihpsdr The hardware shopping list includes. RaspberryPi 3, 7″ Official Raspberry Pi LCD, 8 push buttons, 4 rotary encoders, case and power supply.
All the items were mounted in a 12x7x2″ aluminium case obtained from Mouser, The display was held in place with plastic channel finishing strips from B&Q.

More details at g4fre radio blog.

Free PCB Sunday: Pick your PCB

Posted on Sunday, April 2nd, 2017 in Free PCBs by DP | 32 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:

(more…)

App note: How to select the Triac, ACS, or ACST that fits your application

Posted on Sunday, April 2nd, 2017 in app notes by DP | No Comments

an_stm_an4363

Choosing the right AC switch for your application based on specification like current rating, voltage rating and triggering quadrant. Here’s an app note from STMicroelectronics to guide you on selecting the right part. Link here (PDF)

This document gives basic guidelines to select the AC switch device according to the targeted application requirements. These guidelines will allow the appropriate Triac, ACS or ACST to be selected, for most of the applications. Some very specific cases could require a higher level of expertise to ensure a reliable and efficient operation.

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