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ถูกปรับปรุง 1 ชั่วโมง 29 min ก่อน

PocketPi MK2

อังคาร, 05/21/2019 - 06:33

 A smaller thinner PocketPi from Facelesstech:

Thinner with a simpler design but packing the same feature as before. At its heart is a raspberry pi zero W with a 3.5″ screen 480×320. It has all the GPIO pins available what aren’t being used by the screen. Its powered by a 2500mAh battery and has one full sized usb port. Its controlled by a bluetooth keyboard with trackpad

More details on Facelesstech blog.

Check out the video after the break.

App note: Color sensing improves look and feel of smart products

จันทร์, 05/20/2019 - 00:00

Renesas’ white paper on applications of RGB sensors. Link here (PDF)

Color printers also require an accurate sensor to ensure that during calibration and printing the correct amount of ink is being deposited onto the paper—an essential requirement when the target output is for color photographs.

App note: Eye safety for proximity sensing using infrared light-emitting diodes

อาทิตย์, 05/19/2019 - 20:10

A guide to human eye safety for designers of consumer products, app note from Renesas. Link here (PDF)

Active Proximity Sensing for Consumer products requires the use of a light-emitting component to illuminate the target object to be detected at some distance from the sensor. Typically, product designers do not want the illumination to interfere with the other functions of the product, or to distract the user during normal use. Therefore, Infrared Light-emitting Diodes (IR-LEDs) are used as the light-emitting components for proximity sensing. To further reduce the user awareness of the proximity function, the IR-LED and the proximity sensor are located under heavily tinted – but, infrared-transmitting – glass. While remaining unaware of any illuminating light source, the consumer indeed is exposed to low-levels of infrared radiation. All consumer products that emit light radiation – whether visible, ultraviolet, or infrared – must adhere to international standards that specify exposure limits for human eye safety.

Tiny thermocouple thermometer

ศุกร์, 05/17/2019 - 06:20

Johnson Davies built a tiny thermocouple thermometer based on an ATtiny85 measuring boiling water:

This project describes a thermocouple thermometer, capable of measuring temperatures up to +1350°C, using just an ATtiny85 and an OLED display.

More details on Technoblogy.

BLE400 with the Bus Pirate

จันทร์, 05/13/2019 - 19:00

@TheGrSpy tweeted, “Bus Pirate is talking nicely to the BLE400 from @Waveshare wearing the awesome nRF51822 SoC”

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

App note: Basics on decoupling

จันทร์, 05/13/2019 - 00:00

See AVX technical note on how capacitors filter out transients in high speed digital circuits. Link here (PDF)

This paper discusses the characteristics of multilayer ceramic capacitors in decoupling applications and compares their performance with other types of decoupling capacitors. A special high-frequency test circuit is described and the results obtained using various types of capacitors are shown.

App note: Hand soldering tutorial for fine pitch QFP devices

อาทิตย์, 05/12/2019 - 20:00

No SMD tools removal and soldering of QFP packages tutorial from Silicon labs. Link here (PDF)

This document is intended to help designers create their initial prototype systems using Silicon Lab’s TQFP and LQFP devices where surface mount assembly equipment is not readily available. This application note assumes that the reader has at least basic hand soldering skills for through-hole soldering. The example presented will be the removal, cleanup and replacement of a TQFP with 48 leads and 0.5 mm lead pitch.

Building a Raspberry Pi UPS and serial login console with tinyK22 (NXP K22FN512)

เสาร์, 05/11/2019 - 06:53

Erich Styger has been working on a UPS with the Raspberry Pi to cover a short power out:

There are different ways to ruin a Linux system. For the Raspberry Pi which uses a micro SD card as the storage device by default, it comes with two challenges:
1.Excessive writes to the SD card can wear it out
2.Sudden power failure during a SD card write can corrupt the file system
For problem one I do I have a mitigation strategy (see “Log2Ram: Extending SD Card Lifetime for Raspberry Pi LoRaWAN Gateway“). Problem two can occur by user error (“you shall not turn it off without a sudo poweroff!”) or with the event of a power outage or black out. So for that problem I wanted to build a UPS for the Raspberry Pi.

Project info on MCU on Eclipse site.

Minimal ATSAMD21 computer

ศุกร์, 05/10/2019 - 06:56

Johnson Davies shared detailed instructions of how to build an ATSAMD21-based computer on a prototyping board using a 32-pin ATSAMD21E:

If you’re looking for something more powerful than the ATmega328 in the Arduino Uno a good choice is the ATSAMD21. This is an ARM Cortex M0+ processor with up to 256KB flash memory, 32KB RAM, and a 48MHz clock, so it’s substantially better equipped than the ATmega328. In addition it has a USB interface built in, so there’s no need for a separate chip to interface to the serial port.
Arduino have designed several excellent boards based on the ATSAMD21, such as the Arduino Zero or smaller-format MKRZERO. However, these boards are an expensive way to use an ATSAMD21 as the basis for your own project, and they probably include many features you don’t need.

More details on Technoblogy.

#FreePCB via Twitter to 2 random RTs

พุธ, 05/08/2019 - 06:30

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.

Arduino interface for TFA9842AJ power amplifier

อังคาร, 05/07/2019 - 21:54

Dilshan Jayakody writes, “I tested a couple of TFA9842AJ based amplifiers in the last couple of years. The main reason I liked TFA9842AJ is its simple, clean design, wide operating voltage, and high-quality bass-rich audio output.  Thanks to it’s built-in DC volume control circuit this audio amplifier can easily interface with MCU. In this article, we provide a generic TFA9842AJ module which works with most of Arduino boards, MCUs and SOCs.”

See the full post in his blog.

App note: 3V DACs used in ±10V applications

จันทร์, 05/06/2019 - 00:00

Boosting DAC’s output to drive larger voltage tackled in this app note from MAXIM Integrated. Link here (PDF)

Many modern systems have the majority of their electronics powered by 3.3V or lower, but must drive external loads with ±10V, a range that is still very common in industrial applications. There are digital to analog converters (DACs) available that can drive loads with ±10V swings, but there are reasons to use a 3.3V DAC and amplify the output voltage up to ±10V.

App note: Tire pressure monitor system

อาทิตย์, 05/05/2019 - 20:00

NXP Semiconductor’s implementation of Tire pressure monitor (TPM) system. Link here (PDF)

The Tire Pressure Monitoring System Reference Design consists of five modules: four tire modules and a receiver module. The tire modules consist of the MPXY80xx, the RF2, a battery, several discrete components, and a printed antenna. The receiver module has the MC33954, the KX8, five LEDs to display the status, a battery, a power supply connection, and an RS-232 serial interface.

Semiconductor radioactivity detector: part 3

เสาร์, 05/04/2019 - 21:51

Robert Gawron has made a new version of his radioactivity detector project and wrote a post on his blog detailing its assembly:

In this post I will present a new hardware version of my sensor, older versions are described in part I and part II. In comparison to the previous one, sensitivity is roughly x10 more sensitive.
In previous version, tin foil window for photodiodes was very close to the BNC sockets and because enclosure was small, it was hard to place a sample close enough. Not it’s better, however, if I would choosing again, I would use metal enclosure similar to those used in PC oscilloscopes and put BNCs on front panel, power socket on rear panel and tin foil window on top. This would allow me to easier access for debugging- now I have to desolder sockets to get to photodiodes or to bottom side of PCB.

See the full post on his blog.

The Nixie tube filadometer – a Nixie tube filament meter for your 3D printer

พฤ, 05/02/2019 - 22:17

Dr. Scott M. Baker made a Nixie tube filament meter for his 3D Printer:

First, I decided to upgrade from the Raspberry Pi Model B to a more recent Raspberry Pi Zero W that I had on hand. Wired Ethernet is so ~ 2013 after all, and wireless would be a lot more convenient. Next, I designed a 3D printed case for it, as my old laser-cut-acrylic-and-glue case also looked very dated. Finally, I replaced the software with a new program designed to poll the data from my octoprint server. In less than an afternoon, I had turned the old temperature/humidity display into something useful.

See the full post on his blog.

Check out the video after the break.

Open Trickler: The DIY smart powder trickler

พุธ, 05/01/2019 - 21:53

Eric Higgins has a nice build log on his Open Trickler project a bluetooth-enabled smart powder trickler from off-the-shelf parts for under $60:

Fundamentally, this is not a hard problem to solve. Read the value from the scale, run a motor that moves powder into the scale, turn off the motor when the scale reads the target weight. As with many projects, the devil’s in the details and there was plenty of trial-and-error during the development process to reach a working prototype.
In this project, a Raspberry Pi is used to read the weight from the scale and run a small vibration motor (like those in mobile phones) to trickle powder. An app on your phone or tablet connects to the Raspberry Pi over Bluetooth, and is used to set the target weight and start/stop the automatic trickling process.

See the full post on Ammolytics blog.

Check out the video after the break.

#FreePCB via Twitter to 2 random RTs

พุธ, 05/01/2019 - 05:00

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.

Teardown of a LogiMetrics A300/S traveling wave tube amplifier

อังคาร, 04/30/2019 - 21:42

 LogiMetrics A300/S TWTA teardown by Kerry Wong:

I just picked up a LogiMetrics A300/S 2 GHz to 4 GHz (S band) traveling wave tube amplifier (TWTA) on eBay. I had done an extreme teardown of an HP 493A TWTA a while ago and it was quite fascinating to see what’s inside of a TWT. This LogiMetrics A300/S was made from the late 70’s and unlike the HP 493A it was made entirely using solid state devices (e.g. transistors and ICs), the TWT itself of course remains a vacuum tube.

See the full post on his blog.

Check out the video after the break.

16 x 2 LCD controlled via power line

จันทร์, 04/29/2019 - 23:47

Vinod blogged about a 16×2 LCD with data over power line:

Then I just thought why even 1 wire for data? Because we can easily multiplex the 1 wire data line with the Vcc line by keeping a diode + capacitor combination towards the LCD power supply pin. I am using an arduino board to do the serial to parallel conversion + some packet parsing and lcd backlight brightness control. I am not a huge fan of Arduino but for this simple proof of concept, I don’t want to bring out a Makefile folder with muliple files. I picked the Arduino UART RX as the serial receiver. RX pin is connected directly to the input Vcc, but before the schottky diode.

See the full post in his blog.

Check out the video after the break.

App note: Crystal oscillator troubleshooting guide

จันทร์, 04/29/2019 - 01:35

App note from NXP Semiconductors dealing with oscillators in microcontrollers. Link here (PDF)

Most microcontrollers can use a crystal oscillator as their clock source. Other options include external canned oscillators, resonators, RC oscillators, and internal clocks. The main advantages of a crystal oscillator are frequency accuracy, stability, and low power consumption. However, high reliability is needed to fully benefit from these advantages.