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App note: Increasing accuracy in feedback circuits and voltage dividers with thin film chip resistor arrays

จันทร์, 01/21/2019 - 00:00

App note from Vishay on using chip resistors to achieve long-term stability. Link here (PDF)

Thin film chip resistor arrays consist of several resistors of equal or different values combined in one package. During the manufacturing processes and the device’s lifecycle, all the particular resistors virtually experience identical conditions, which allow the specification of their relative tolerances, relative temperature coefficients, and even a relative resistance drift. These relative parameters provide precise and stable resistance ratios and far better long-term stability of feedback circuits and voltage dividers compared to discrete resistors.

App note: Custom magnetics – What are they and when do you need them?

อาทิตย์, 01/20/2019 - 21:05

Consideration factors before going to custom magnetic request from manufacturer, an app note from Vishay. Link here (PDF)

There are many manufacturers that claim they build custom magnetics. However, there is often confusion as to what constitutes custom magnetics and whether or not a designer actually needs them or can afford them. This article will clarify what custom magnetics are, help designers determine if they are needed, and explain how to engage with a custom magnetics supplier.

The Boris Beacon – A 1mW solar powered hifer beacon

ศุกร์, 01/18/2019 - 20:17

Dave Richards (AA7EE) has written an article detailing his 1mW solar-powered HiFER beacon project, the Boris Beacon:

In this post from May of last year, I detailed the construction of a 1mW solar-powered HiFER beacon. I named it the Boris Beacon, in tribute to my neighbor’s cat. The beacon was never mounted permanently outside. I kept it indoors, powered from a small solar panel in the window, and feeding an “antenna” of sorts, consisting of the original dipole wires folded up into two small bundles. Obviously, I had no serious intention of it being heard by anyone; I just liked having it come on every day when the sun came up, and transmitting until later in the day, when the light was too low to sustain operation.

See the full post on his blog.

Viewing ARM CPU activity in real time

ศุกร์, 01/18/2019 - 19:13

Jeremy Bentham writes:

In previous blog posts, I have described how an FTDI USB device can be programmed in Python to access the SWD bus of an ARM microprocessor. This allows the internals of the CPU to be accessed, without disrupting the currently running program.
In this blog I take the process one step further, and add a graphical front-end, that shows the CPU activity in real time

More details on Iosoft blog. Source files are available on GitHub.

#FreePCB via Twitter to 2 random RTs

พุธ, 01/16/2019 - 06:38

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.

DIY Arduino based RC transmitter

อังคาร, 01/15/2019 - 00:58

 

Dejan over at HowToMechatronics posted a detailed how-to on building DIY Arduino RC transmitter:

Now I can wirelessly control any Arduino project with just some small adjustments at the receiver side. This transmitter can be also used as any commercial RC transmitter for controlling RC toys, cars, drones and so on. For that purpose it just needs a simple Arduino receiver which then generates the appropriate signals for controlling those commercial RC devices. I will explain how everything works in this video through few examples of controlling an Arduino robot car, controlling the Arduino Ant Robot from my previous video and controlling a brushless DC motor using an ESC and some servo motors.

More details on HowToMechatronics’ project page.

Check out the video after the break.

PLA dielectric strength measurement

จันทร์, 01/14/2019 - 23:55

Kerry Wong did some experiment measuring the dielectric breakdown voltage of PLA:

In my previous post, I designed and 3D printed a high voltage connector for my Bertan 225-20R high voltage power supply. The silicone high voltage wire I ordered had finally arrived so I made a couple of cables using the connectors I printed. A few of my viewers had questioned the suitability of using PLA as printing material in high voltage applications so I decided to measure the dielectric breakdown voltage of PLA and gather some real-world data.

See the full post on his blog here.

Check out the video after the break.

App note: Simplify home audio systems With the PCM9211 – A versatile audio interface transceiver

จันทร์, 01/14/2019 - 00:00

A digital interface PCM9211 from Texas Instruments app note. Link here (PDF)

Large-screen HDTVs are selling in huge volumes over last few years, primarily driven by amazing improvements in picture quality & form factor (thinner screens). The form factor constraints from having skinny screens result in tiny built-in speakers that are undersized, under-powered and are typically aimed at wrong direction. Hence sound bars have exploded in popularity as complementary audio system by providing a sound experience that more closely matches the TV’s life-like pictures. In addition, with release of HDMI 2.1 specification we finally have a nocompromise audio solution for HDMI as part of the eARC [enhanced Audio Return Channel]. This tech note reviews eARC and simplified Sound Bar design using PCM9211 and how to interface eARC signals with PCM9211.

App note: Noise suppression for wireless headphones

อาทิตย์, 01/13/2019 - 20:00

Wireless headphone interference investigation from muRata. Link here

Recently, the popularity of wireless headsets has been growing as the number of situations where people “play sports while listening to music” increases.

Bluetooth is frequently used for communication between smartphones and headsets. However, audio can skip due to communication errors, so countermeasures are required.

This is an extremely important point of user evaluation and a difficult issue to resolve.
Here we depict an actual case to explain the interference mechanism in the device which causes the audio to skip, and key points for improvement to introduce useful countermeasures for solving the problem.
We hope that you will use it as a guide to help your design work proceed more smoothly.

MusiCubes project

อังคาร, 01/08/2019 - 06:59

Michael Teeuw published a new build:

Now that the MusiCubes tray is assembled and the RFID-sensor and LEDs are working as expected, It’s time to add the last feature of the original concept: invisible capacitive touch sensors to control the volume of the music.

See the full post on Xonay Labs blog. Be sure to see Part 1 and 2.

Check out the video after the break.

App note: The Phytochrome system – Why use far-red?

จันทร์, 01/07/2019 - 00:00

App note from Würth Elektronik on why plants evolved to use far-red wavelengths and why it is essential for them. Link here (PDF)

The light requirement of plants is now known to be far more complex than originally thought leading to the development of numerous LED technologies that produce a variety of different light spectra, both monochromatic and polychromatic.

Far-red encompasses wavelengths 700 – 800 nm, a region of light that is on the edge of visibility in humans. However, these wavelengths have been proven to result in faster growth, increased biomass and better sensory characteristics (e.g. smell, taste, texture, color).

Free PCB Sunday: Pick your PCB

อาทิตย์, 01/06/2019 - 23:31

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Be sure to use a real e-mail in the address field so we can contact you with the coupon.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.
  • PCBs are scrap and have no value, due to limited supply it is not possible to replace a board lost in the post

Be the first to comment, subscribe to the RSS feed.

App note: CeraLink® Capacitors

อาทิตย์, 01/06/2019 - 20:00

Compact and high capacitance ceramic capacitors from TDK electronics. Link here (PDF)

CeraLink is a family of very compact capacitors for stabilizing voltages in the DC link. They are therefore suitable for use as either snubber or DC link capacitors. These products are based on PLZT ceramics and are designed to provide engineers with compact components optimized for fast switching converters, converters with very tight space requirements and converters that need to withstand high operating temperatures. The basic component is a ceramic chip which either is manufactured with lead frames or which can be combined modularly to form capacitors with higher capacitance values.

Regaining debug access of NXP i.MX RT1064-EVK executing WFI

พฤ, 01/03/2019 - 22:02

Erich Styger writes:

Working with low power modes can be challenging. It can severely affect debugging capabilities of a microprocessor or microcontroller. I ported a FreeRTOS application using the Tickless Idle Mode to the NXP i.MX RT1064 board, and all of a sudden, the board was unresponsive to any debugger connection. Luckily the board was not really bricked, but it took me while to find a way to recover it. So for when you end up in a situation with a ‘bricked’ i.MX RT1064 board, this article might be helpful for you to recover it.

More details on MCU on Eclipse blog.

Polar Coaster drawing machine

พฤ, 01/03/2019 - 18:00

Barton Dring designed and built a Polar Coaster drawing machine to draw custom, round drink coasters:

I recently decided to update the Polar Coaster project. The primary reason was to update the controller to use Grbl_ESP32 firmware. I also thought I could make it smaller, lighter and remove a little cost.
The old controller was not custom made and just sort of tacked onto the back. This increased the size and didn’t look very good. It had a Bluetooth module, but you still had to stream the gcode. You could use an Android app, but that was still a little awkward.
The controller runs Grbl_ESP32. This was recently updated to include pen machine features. This allows precise control and calibration of the pen servo. You can control the speed, timing and endpoints of the servo travel.

Project info at Buildlog.Net blog.

Check out the video after the break.https://www.youtube.com/watch?v=7_aS0PbP8HY

Happy New Year 2019 from Dangerous Prototypes

อังคาร, 01/01/2019 - 12:37

Happy New Year!

Thank you for reading the blog and being part of our community in 2018! We’re looking forward to more open hardware projects, more how-tos, more videos, more free PCBs, and more hacking in 2019.

App note: Linear regulator specifications

จันทร์, 12/31/2018 - 00:00

Thorough items on a linear regulator datasheet provides valuable details about its proper usage discussed in this App note from ROHM semiconductor. Link here (PDF)

A linear regulator data sheet includes a specifications table that lists output voltage values and precision. Besides, very important information such as maximum ratings, operating conditions and characteristic graphs are described in the table.

App note: Connecting LDOs in parallel

อาทิตย์, 12/30/2018 - 20:00

App note from ROHM semiconductor on combining LDOs for higher load capacity. Link here (PDF)

When you want to increase the output current capacity of an LDO, or when the power dissipation of a single LDO is insufficient, you might think of connecting LDOs in parallel if you need to disperse the dissipation using two LDOs. This application note provides some hints on how to connect LDOs in parallel.

Multislope ADC bring up (dual slope)

เสาร์, 12/29/2018 - 06:56

Nava Whiteford has been working on a Multislope ADC:

I’ve been playing with a multislope ADC design. Multislope ADC are often used in high end multimeters, and as I have a mild obsession with 8.5 digit multimeters, I wanted to try making a multislope ADC.

See the full post on 41J blog.

BMP180 based USB atmospheric pressure monitor

พฤ, 12/27/2018 - 06:40

Dilshan Jayakody published a new build:

We initially developed this USB atmospheric pressure monitor to study some operating characteristics of Bosch BMP180 sensor. BMP180 is low cost sensor to measuring barometric pressure and temperature. According to the data sheet this sensor can use to measure pressure ranging between 300hPa to 1100hPa. This sensor is introduced couple of years back but still it is popular due to lower cost and simplicity of it’s interface.

See the full post on his blog.