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Merry Christmas!

Posted on Tuesday, December 25th, 2018 in Holiday by DP | No Comments

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Merry Christmas and Happy Holidays to all. May you find many PCBs and other electronics wizardry under your tree or pole.

Remember, support is available on Christmas. Just give us a shout in the forum.

Free PCB Sunday: Pick your PCB

Posted on Sunday, December 23rd, 2018 in Free PCBs by DP | 4 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: Basics and low-cost solution proposals to move from legacy USB2.0 connector to USB Type-C™ connector with STM32 devices

Posted on Sunday, December 23rd, 2018 in app notes by DP | No Comments

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App note from STMicroelectronics about interfacing STM32 legacy USB 2.0 to USB Type-C. Link here (PDF)

This application note is a guideline to introduce this USB Type-C connector onto platform to replace legacy USB2.0 connectors. It introduces some basis of the two new standards USB Type-C™ and the USB Power Delivery.

App note: Quad-SPI (QSPI) interface on STM32 microcontrollers

Posted on Sunday, December 23rd, 2018 in app notes by DP | No Comments

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Extend memories by using external high speed memories interfaced to Quad-SPI modules on STM32 micros, app note from STMicroelectronics. Link here (PDF)

This application note describes the Quad-SPI interface on the STM32 microcontrollers and explains how to use the module to configure, program, and read external Quad-SPI memories. It describes some typical use cases to use Quad-SPI interface based on some software examples from the STM32Cube firmware package and from the STM32F7 application notes.

The CAN bus

Posted on Wednesday, December 19th, 2018 in how-to by DP | No Comments

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Jean-Claude has made a series of blog posts on using the Controller Area Network (CAN) bus:

This is the first of what I expect to become a multi-part article series on the CAN bus. I’d like to describe the features of CAN which I find particularly elegant and useful, and will introduce a simple driver I have implemented for it as part of the JeeH library. Along the way, I’ll try to illustrate its use with a variety of small demo apps, running on either a Blue Pill (i.e. F103), or one of the STM32F4 µC families.

Check out Jeelabs’ 6-part blog post here:
Part 1 – Intro
Part 2 – Access
Part 3  – STM32
Part 4 – JeeH API
Part 5 – Demo
Part 6 – Single-wire

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, December 18th, 2018 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.

Dashcam GPS module

Posted on Tuesday, December 18th, 2018 in Teardowns by DP | No Comments

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A look at the Dashcam GPS module by Electronupdate:

After a 4 year run the dashcam on my car stopped working: a fault seems to have developed in the power system.  It was mounted to the window by what I thought was just a simple mechanical mount… on further analysis it became clear that the GPS receiver was part of the mount (makes sense as the user normally glues this part to the windscreen).

More details on Electronupdate blog.

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

RTC based automatic LED lamp

Posted on Monday, December 17th, 2018 in DIY, LEDs, PIC by DP | No Comments

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Dilshan Jayakody published a new build:

This is real-time clock based automatic LED lamp which we originally designed to use as night light. This lamp can programmed to turn on and off at the specific time of the day. For example, it can program to turn on at 6 PM on each day and to turn off at 4 AM next day.
The core component of this project is PIC16F883 MCU and it’s firmware is developed using MikroC Pro for PIC. We select this MCU because of it’s 7 KB flash memory, I2C, UART, E2PROM and built-in 8-bit and 16-bit timers.

See the full post on his blog.

Free PCB Sunday: Pick your PCB

Posted on Sunday, December 16th, 2018 in Free PCBs by DP | 4 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 avoid chipLEDs sticking to cover tape during automated tape-and-reel assembly

Posted on Sunday, December 16th, 2018 in app notes by DP | No Comments

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Investigative app note from Vishay on preventing too light components from sticking on the cover tape of their reel. Link here (PDF)

Customers have informed Vishay that 0603 LEDs (ChipLEDs) supplied in tape and reel format sometimes stick to the PSA cover tape that is peeled off from the carrier tape during the assembly process. This application note describes the problem and provides a summary of precautions that can be used to prevent this unwanted effect from happening.

App note: A simple alternative to analog isolation amplifiers

Posted on Sunday, December 16th, 2018 in app notes by DP | No Comments

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A linear isolation amplifier from Silicon Labs app note. Link here (PDF)

Analog circuits sometimes require linear (analog) signal isolation for safety, signal level shifting, and/or ground loop elimination. Linear signal isolation is typically difficult to implement, costly, and often exhibits mediocre performance. While the design community thirsts for a flexible and inexpensive linear isolator solution, it is the analog isolation amplifier (ISOamp) that most often captures the socket.

WBR-Oscar regen receiver

Posted on Friday, December 14th, 2018 in DIY, RF by DP | No Comments

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A nice write-up on Sheldon’s (N6JJA) version of N1BYT’s WBR regenerative receiver:

This article is broken into two parts. First comes the “Oscar” preselector/preamplifier. As I said, I intended it to be either part of the overall receiver or used as a standalone where desired. The second part deals with the WBR upgrades. Both designs were built using the same techniques and I’ve tested both and found that—especially in concert—they do about as well as some of my boat anchors! So if your soldering iron is ready, I’ll start by describing “Oscar.”

Via Dave Richards AA7EE Blog.

Homebrew SDR HF transceiver

Posted on Thursday, December 13th, 2018 in SDR by DP | No Comments

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Simonhk (G0FCU) wrote a series of posts on building homebrew SDR HF transceiver:

However, what you might notice is the presence of image products in the waterfall. The processing of the signal suppresses all but the very strongest of these so they don’t appear as audio but it is mighty confusing when they are on the waterfall but actually not there (if you see what I mean)!
I am in the process of building a QSD or Tayloe Detector, which should provide better rejection of images. I have breadboarded one of these, it works but not very well. I think that this might be due to the length of leads I have on the breadboard so I am trying to use Eagle CAD to design a circuit board to overcome these problems.

Check out the video after the break.

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Guitar Amp builder notes — AF power amplifier dummy load

Posted on Wednesday, December 12th, 2018 in DIY, tools by DP | No Comments

DSC_2129-1 (1)Vasily Ivanenko has written an article detailing his AF dummy load project:

I’ll describe a simple 8, or 4 Ω dummy load to test your home brew guitar power amplifiers.
Low cost 16 Ω / 25W wire wound, aluminum shell, chassis mount resistors seem abundant.  I got mine on eBay.  Wire wound resistors vary in quality, design and tolerance. Some even exhibit low inductance by winding with an Ayrton-Perry bifilar technique.  Resistor tolerances range from 10% down to ± 0.5 % + 0.05 Ω.  Typical manufacturer power ratings are done at 25C, however, these devices are meant to sit on a heat sink when used and that’s why the aluminum housing contains 2 relatively large mounting holes.

Project info on QRF HomeBuilder blog.

Building a direct conversion receiver

Posted on Tuesday, December 11th, 2018 in DIY, how-to by DP | No Comments

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Ryan Flowers over at MiscDotGeek posted a how-to on building a direct conversion receiver:

In the first installment of this series, we discussed why we’re building a Direct Conversion receiver and talked about some basic ideas. In this installment, we explore what it takes to make the leap from a printed schematic to something physical that works. Follow along!

More details at MiscDotGeek.com.

App note: BLDC with hall effect sensors using SCT on LPC84x

Posted on Sunday, December 9th, 2018 in app notes by DP | No Comments

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Motor control on LPC84x MCU app note from NXP. Link here (PDF)

This application note describes an implementation of brushless DC motor control with hall effect sensors using the SCTimer/PWM on LPC84x.

App note: Ambient light sensor SFH5701

Posted on Sunday, December 9th, 2018 in app notes by DP | No Comments

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App note from OSRAM on their ALS device SFH5701, its operation and application method. Link here (PDF)

The SFH5701 is a small, two-wire, linear output current ambient light sensor (ALS) with current amplifier and dark current compensation. The ALS is capable of resolving a wide range of ambient light levels (10 mlx – 10 klx) tailored to the spectral response of the human eye and operational from -40 °C to 100 °C.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, December 7th, 2018 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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Battery switch

Posted on Friday, December 7th, 2018 in open source by DP | 1 Comment

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An open source battery switch project from Open Electronics:

Given two batteries, it chooses the one to connect to the load based on the voltage measured at their poles. It can also be used to switch DC power supplies.

More details at open-electronics.org.

Teensy 3.6 as standalone mediator between USB MIDI and Eurorack

Posted on Friday, December 7th, 2018 in Arduino, how-to by DP | No Comments

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Sebastian writes:

USB MIDI controllers (such as Launchpad Mini Mk II for example) are common and often quite low in cost.
To interface such a controller with a Eurorack synth system, often a host computer and a MIDI to CV interface might be used. The host computer would take USB MIDI data from the MIDI controller, perhaps store and manipulate that data in some way (e.g. a sequence), using a MIDI to CV converter to then control a Eurorack synth system.
It would be useful to use USB MIDI controllers with Eurorack synth systems without needing a computer and MIDI to CV interface in between the two.
Teensy 3.6 is a great microcontroller that can be programmed using the Arduino IDE. A very useful feature of the Teensy 3.6 is the USB host port.

See the full post on his blog here, Little-Scale.

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

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