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13.8V 5A power supply

Posted on Thursday, February 28th, 2019 in power supply by DP | 1 Comment

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Dilshan Jayakody published a new build:

13.8V power supplies are commonly used in armature radio experiments. Most of the portable armature radio transceivers are designed to work with a 13.8V power source. We mainly build this power supply unit to power some of our armature radio circuits and modules.
This design is based on the popular LM338 5A voltage regulator. We choose this regulator because of to it’s higher current rating, short-circuit protection feature and higher availability.

See the full post on his blog.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 26th, 2019 in Free PCBs by DP | No Comments

BP

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.

Weather station project

Posted on Tuesday, February 26th, 2019 in wireless by DP | No Comments

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Alvaro Prieto has been working on a wireless weather station project:

After playing around with the breakout boards, I decided it was time to integrate it all in a single board. I named it Chaac.
This is where I ran into issues with MBED. Making the board support package (BSP) for a custom board was not trivial. Another issue was that I couldn’t get the low-power modes working quite right. At the same time, I decided to ditch GPS, since the weather station is unlikely to move without my knowledge . With the new requirements, I ended up switching to an STM32L432KC based board.

See the full post on his blog.

App note: Thermal consideration of flash LEDs

Posted on Sunday, February 24th, 2019 in app notes by DP | No Comments

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Pulsed LED application like flash LEDs requires adequate thermal management to counter the heavy heat caused by larger current, here’s an app note from OSRAM discussing on thermal management of LEDs. Link here (PDF)

This application note focuses on how to develop an adequate thermal management for LEDs in camera flash applications. It provides information on critical factors and the thermal properties of LEDs during a range of operation modes as well as information on how to develop an adequate thermal management in flashlight applications.

App note: Dimming InGaN LEDs

Posted on Sunday, February 24th, 2019 in app notes by DP | No Comments

an_osram_AN042

App note from OSRAM on InGaN LEDs dimming method without penalty on its wavelength. Link here (PDF)

While the InGaN technology produces the brightest light output across Blue, Deep blue, Verde, True green and White, it is important to understand that the wavelength of the light emitted depends on the forward current. In order to avoid shifts in the color, the dimming strategy must be considered carefully.

ATtiny13 – 8bit mono class D amplifier

Posted on Thursday, February 21st, 2019 in AVR, how-to by DP | No Comments

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Łukasz Podkalicki shared a how-to on building a Class D amplifier on ATtiny13:

I always wonder whether it is possible to make an amplifier of class D on ATtiny13 or not. Some time ago I found George Gardner’s project based on ATtiny85 – TinyD. It was a sign to start challenging it with ATtiny13. It took me a few hours but finally I made it! The code is very short and useses a lot of hardware settings which has been explained line-by-line in the comments. The project runs on ATtiny13 with maximum internal clock source (9.6MHz). It gave me posibility to use maximum of hardware PWM frequency (Fast PWM mode).

See the full post on his blog.

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

Building the ultimate USB power distribution system

Posted on Thursday, February 21st, 2019 in DIY, USB by DP | No Comments

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Dr. Scott M. Baker published a new build:

My goals include:
1. The ability to switch each device on/off with a rocker or toggle switch
2. Current limiting capability via a fuse or similar device
3. Overvoltage protection
4. Visual indicator (LED) of operational status
5. Multiple independent outlet

See the full post on his blog.

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

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 19th, 2019 in Free PCBs by DP | No Comments

BP

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.

Variable Frequency Drive

Posted on Tuesday, February 19th, 2019 in hacks by DP | No Comments

20190202_AntriebSchaublin-600

Lukas Fässler over at Soldernerd wrote an article detailing his homemade VFD drive for his Schaublin 102 lathe.

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

Outdoor UV index sensor

Posted on Tuesday, February 19th, 2019 in how-to, sensors by DP | No Comments

Outdoor UV index sensor

A detailed instructions of how to build this outdoor UV index and ambient light sensor from Mare & Gal Electronics:

The VEML6075 senses UVA and UVB light and incorporates photodiode, amplifiers, and analog / digital circuits into a single chip using a CMOS process. When the UV sensor is applied, it is able to detect UVA and UVB intensity to provide a measure of the signal strength as well as allowing for UVI measurement.

Semiconductor radioactivity detector – part 2

Posted on Tuesday, February 19th, 2019 in hacks, how-to by DP | No Comments

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Robert Gawron has been working on a radioactivity detector, that is available on GitHub:

There are many ways to measure radioactivity level, semiconductor detectors sense interactions between ionizing radiation and p-n junction. Because in hobbyist area most popular are Geiger-Muller based detectors (in short: not a semiconductor but lamp based devices), I think it’s a cool idea to take a look at this approach.
In this post I will present such home-made sensor and a set of software to parse collected results.

See the full post on his blog. Be sure to see Part 1 here.

NFC antenna tuning without a VNA

Posted on Monday, February 18th, 2019 in PCBs by DP | No Comments

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Fred writes:

Recently I started work on a new board. This one will be a front door entry system, so I decided to go with something that could read my NFC implant but also had a numeric keypad for the kids (and anyone else) to use. Not everyone wants to be chipped. Crazy, isn’t it? I’ll write more up on the board when it gets closer to completion, but for this post I’m going to concentrate on a small PCB antenna that’s intended for use with a tiny implanted tag. I’ve successfully used a wirewound inductor before, but I decided it was time to try a PCB trace antenna. This is the most common way to make an NFC reader, but nobody seems to have tried to tune one for an implant – probably because it means it will be worse at reading larger tags. Anyway, this is about creating a small PCB antenna and more importantly tuning it so that it read well.

Check out the video after the break.

More details on 0xFRED blog.

(more…)

App note: Securing vibration motor leads and wires

Posted on Sunday, February 17th, 2019 in app notes by DP | 1 Comment

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App note from Precision Microdrives on how to properly connect wires on to vibration motors for reliability. Link here

Vibration motors require electrical power, which must be delivered by wires or PCB tracks to the motor. Precision Microdrives vibrating motors are available in a range of connector forms. From stock, they are available with factory installed leads, terminals, PCB solder pins, or as PCB SMT / SMD options. Solder pins and SMT motors have the advantage of being mounted directly onto the PCB which simplifies the connection process.

App note: Vibration Motors – Voltage Vs Frequency Vs Amplitude

Posted on Sunday, February 17th, 2019 in app notes by DP | No Comments

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All about vibration motors and how its frequency and amplitude be controlled in this app note from Precision Microdrives. Link here

We’re often asked how to adjust the vibration amplitude or frequency of our various vibration motors. In this article, we’ll look at how simple it is, why it can be useful, and how we can predict the behaviour of a motor using the driving voltage and Typical Performance Characteristics graph.

An Arduino version of Brooks Shera’s GPSDO

Posted on Monday, February 11th, 2019 in Arduino by DP | No Comments

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Jeff (aka K6JCA) has a great write-up on implementing the Brooks Shera Phase-Locked Loop GPSDO on an Arduino Platform:

This blog post is a continuation of my two earlier GPSDO blog posts. The first one (from a few years back) details a simple Frequency-Locked Loop GPSDO design, based around an Arduino processor. The second (more recent) blog post discusses simulating Brooks Shera’s GPSDO algorithm (from the July, 1998 issue of QST) using The MathWorks Simulink program.
This third blog posts describes my modification of my original Frequency-Locked Loop (FLL) GPSDO to be a Phase-Locked Loop (PLL) GPSDO, and it includes the hardware schematics, Simulink models, and the Arduino code I wrote to implement Brooks Shera’s GSPDO algorithm on an Arduino processor.

More details on K6JCA blog.

App note: Ceramic resonators

Posted on Sunday, February 10th, 2019 in app notes by DP | No Comments

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All about ceramic resonators app note from Abracon. Link here (PDF)

Why Ceramic Resonators? Ceramic resonators stand between quartz crystals and LC/RC oscillators in regard to accuracy. They offer low cost and high reliability timing devices with improved start-up time to quartz crystals.

App note: MELF resistors – The world’s most reliable and predictable, high-performing film resistors

Posted on Sunday, February 10th, 2019 in app notes by DP | No Comments

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App note from Vishay on why MELF resistors are so successful and has no alternative in today’s application. Link here (PDF)

For more than 25 years, Vishay’s MELF resistors have successfully met the demanding requirements of the automotive industry. They offer superior SMD resistor performance in terms of accuracy, stability, reliability, and pulse load capability. The cylindrical construction of MELF devices provides an optimal power rating and pulse load capability related to the mounting space. Continuous development has led to improved long-term stability and moisture resistance, and allows high-temperature operation to + 175 °C.

Serial Star, a 4 in 1 USB serial and I2C converter

Posted on Friday, February 8th, 2019 in PCBs, USB by DP | No Comments

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Jesus Echavarria published a new build:

Here’s one of the last board I design the last year. On 2016, I develop the Dual USB Serial and I2C Converter board. Although this board works fine, it has a couple of lacks. First one, is that to use the both converters, you need two free USB ports. Is a minor problem today with USB hubs, but you need the hub and also two USB wires. And the other problem is that this board uses mini-USB connectors. Of course today you can still find it, but aren’t as common as the micro-USB wires. For this two reasons, I decide to upgrade the board, add the micro – USB connector and put a USB hub inside it. Because I choose a 4-port USB hub, I use also 4 USB serial converters. With some addons, you can select power supply value (5V, 3V3), serial levels (TTL, RS232) and GPIO functions in an independent way for each converter. So, let’s see how works this USB Serial Star, a 4 in 1 USB to Serial and I2C Converter.

More details on Designing Electronics in Spain blog.

Teardown of a Piezoelectric vibrating gyroscope

Posted on Wednesday, February 6th, 2019 in Teardowns by DP | No Comments

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Kerry Wong did a teardown of an old analog piezoelectric vibrating gyroscope:

Gyroscopes nowadays are based on micro-electro-mechanical systems (MEMS) technology. They are low cost and extremely miniaturized. A device combing both a three-axis gyroscope and a three-axis accelerometers (sometimes these devices are referred to as 6DOF devices) such as the MPU-6500 for example can be had in a QFN package as small as 3 mm x 3 mm and under 1 mm in height. Before these MEMS devices gained mainstream popularity however, larger piezoelectric vibrating gyroscopes were used in many consumer electronics devices.

See the full post on his blog.

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

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 5th, 2019 in Free PCBs by DP | No Comments

BP

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.

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