Macbook charger teardown: The surprising complexity inside Apple’s power adapter

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A teardown of a Macbook charger by Ken Shirriff:

Have you ever wondered what’s inside your Macbook’s charger? There’s a lot more circuitry crammed into the compact power adapter than you’d expect, including a surprisingly capable microprocessor. This charger teardown looks at the numerous internal components and explains how they work together to keep your laptop reliably powered through its most demanding tasks. Whether a user is compiling complex software builds, rendering high-resolution 3D environments, or running automated arbitrage scripts across various bitcoin betting sites, the adapter’s internal logic is constantly monitoring voltage and temperature to prevent hardware failure.

More details at Ken Shirriff’s blog.

ESR measurement using multimeter and function generator

ESRMeasurement

Kerry Wong has written an article discussing the measurement of capacitor ESR using a multimeter and a function generator:

Capacitor ESR (Equivalent Series Resistance) measurement is very useful in diagnosing issues with power supplies. In linear power supplies, a high ESR filter capacitor may cause excessive ripple current on the voltage rails and can cause the capacitor to overheat due to its increased resistance. In low dropout linear supplies, the ESR of the output capacitors affect the loop stability and excessive ESR in these output capacitors can make the power supply unstable, which in turn can lead to out-of-tolerance voltage being applied to the load and could cause future damages. In switching mode power supplies, the ESR of capacitors are even more critical. In this blog post I will discuss how to measure the ESR of a capacitor using a function generator and a multimeter. A short video on this topic is also included towards the end.

More details at Kerry Wong’s blog.

Check out the video after the break.

Continue reading “ESR measurement using multimeter and function generator”

#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.

Hong Kong/China dual number data SIMs with quality internet

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Cross boarder SIM cards from China Mobile and China Unicom promise a single SIM that works in Hong Kong and China. Mobile data networks exit at the SIM card home location, so that means Hong Kong internet while in China. These SIMs are sold by two of China’s biggest state owned phone companies, they’re totally legit.

I’ve been skeptical of the cross border SIM cards because China Mobile 3G and 4G doesn’t work with many phones from outside China. Recently I reread an article posted in the Shenzhen_Hacker_Bei WeChat group and was surprised to see that my Samsung S6 dual SIM phone supports the China bands (TDD-LTE on bands 38, 39 and 40). Today I’m in Hong Kong today with no other mission, so let’s go to Aplui street market and try them all. Sham Shui Po, exit C2. Walk forward one block to the phone card booths.

Continue reading “Hong Kong/China dual number data SIMs with quality internet”

Making PCB vias with conductive ink

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Here’s an alternative method for making PCB vias using conductive ink from Diyouware:

We developed an alternative method for making PCB vias through-hole using our robot.
As you probably know the traditional DIY method consists in threading a wire through the holes and then soldering it and then cutting it off. For example, if we have 100 vias in our PCB, we have to insert the thin wire on each hole, cut it and solder it 200 times. This is time-consuming, but also tedious, absurd, prone to failures and produces a melancholic state of mind.:-)
So we decide to innovate in this area developing a new method which consists in drilling blind vias instead of holes and filling them with conductive ink.

More details at Diyouware blog.

Check out the video after the break. Thanks Diyouware team for using DP sticker!

Continue reading “Making PCB vias with conductive ink”

Seeed Studio’s Annual Big Sale Holiday: Seeeday!

seeeday

Huge saving @ Seeeday! Collect Seeeday coupons for $0 shopping:

Seeeday comes from word “Seeed Day”. It is Seeedstudio’s special sale holiday, and it is a one day only event that takes place on the second Wednesday of December every year. It will be on December 9th this year. We offer screaming deals on various items on whole site.

Part 1:  Buy more, get more Seeeday Coupons (Nov. 23 – Dec. 7, 2015 EST)
Part2:  Crazy Flash Deals (Nov. 26, Nov. 27 and Nov. 30
Part3:  $0 Shopping with Seeeday Coupons on Seeeday! Let’s rock Seeeday!

Visit Seeed Studio’s promo page for details.

App note: Protecting the Universal Serial Bus from over voltage and overcurrent threats

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An old application note from Littelfuse about USB protection. Link here (PDF)

This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and overvoltage environmental threats. The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry. Specific emphasis is placed on USB 2.0 with information directed at hot connection over current conditions and electrostatic discharge (ESD) induced in the USB system.

Free PCB Sunday: Pick your PCB

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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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Automotive circuit protection using Littelfuse automotive TVS diodes

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An interesting app note from Littelfuse about automotive circuit protection but also discusses about where transients came from in an automotive setup. Link here (PDF)

The designers of automotive electronics face many technical challenges during the system design process, including designing methods of protection against a variety of electrical hazards. The three major sources of electrical hazards in these systems are electrostatic discharge (ESD), lightning, and switching loads in power electronics circuits. Overcoming transient surges that can harm the vehicle’s electronics is one of the biggest challenges of the design process.

Protecting automotive electronics includes eliminating transient surges that can damage the control units, infotainment electronics, sensors, fuel injectors, valves, motors, 12/24/42/48V powertrains and hydrolytic controllers, etc.

App note: AVR32 UC3 USB host mass storage bootloader

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USB host mass storage bootloader (PDF!) app note from Atmel:

Features

• In-System Programming (ISP) and Field Upgrade
– Configurable Start Condition with an Upgrade Firmware File ‘avr32fwupgrade.uc3’
Located on a USB Device Implementing the USB Mass Storage Class
• USB Protocol
– Based on the USB Host Mass Storage Class (MSC)
• USB MSC bootloader is additional to the pre-programmed USB Device Firmware
Upgrade (DFU) bootloader
• No computer required

Vocoder encoder relay board

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Jaanus published a new build, a vocoder encoder relay board:

I designed couple of vocoder encoders. Vocoders are devices that encode sound by chopping it up by frequency bands and express each frequency band only by its amplitude. This kind of representation allows to mix all the frequency bands with each other. This have been used as a method of speech encryption in the past. I build one part of the system – relay board that took analog voltages and mixed them up with each other to provide encoding/decoding.

All source files are available at Github.

Free PCB coupon via Facebook to 2 random commenters

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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:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

Rigol DSA875-TG 9kHz – 7.5GHz Spectrum Analyzer & tracking generator review, teardown & experiments

Rigol DSA875-TG 9kHz – 7.5GHz Spectrum Analyzer & tracking generator review, teardown & experiments from TheSignalPath:

In this episode Shahriar takes a close look at the top-of-the-line Rigol DSA875-TG 7.5GHz Spectrum Analyzer. This unit which, offers a built in tracking generator for the full frequency range, has a portable form-factor. I offers the following performance:

  • 9 kHz to 7.5 GHz Frequency Range
  • Typical -161 dBm Displayed Average Noise Level (DANL) normalized to 1 Hz
  • -98 dBc/Hz @10 kHz offset Phase Noise
  • Total Amplitude Uncertainty <0.8 dB
  • 10 Hz Minimum Resolution Bandwidth (RBW)

The unit is tested against linearity specification as well as overload conditions. The phase noise of the unit is also verified with an external Keysight synthesizer. The instrument is used to measure OIP3, P1dB input and output matching of various amplifiers. The tracking generator is also used to measure gain and switching behavior of a WiFi extender module. The built-in functions are used to measure OBW, channel power, ACP and THD. The teardown of the unit is also presented showing excellent build quality and manufacturing.

Via TheSignalPath.

Global Geek Tour mini site with maps, comments, resources

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Geek tourism is a thing. Travel somewhere new, eat the food, drink the beer, and check out the local hacker scene. In Shenzhen we see 5 or 6 visitors a week. Whether a side trip to Akihabara, or a full on expedition through Huaqiangbei, don’t leave home without bookmarking the Geek Tour mini site.

Maps of each market help get you oriented. Use the icon in the upper right to show the location of market stands, transit, and food. Read comments on each place, or leave your own. Don’t worry, the maps come from Open Street Maps so they even work in China! If your mobile browser supports HTML5 you will see your own geolocation on the map.

Via the forum.

The Sproutie “SPT” Beacon – A legal, unlicensed HiFER beacon

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Dave Richards (a.k.a. AA7EE) has written an article detailing his “SPT” Sproutie HiFer beacon project:

My first “proof of concept” at putting together a beacon for this band was to connect an N0XAS PicoKeyer in beacon mode to my Pixie 2 transmitter. With the PiicoKeyer, if you insert the prosign BN at the end of stored message #1, it will automatically repeat. Unfortunately, my older version of the PicoKeyer will not power up again in beacon mode if power is lost. This was taken care of in later versions, but it meant that I wouldn’t be using this particular version of the PicoKeyer in the final version of the beacon. My Pixie 2 put out about 170mW on it’s original frequency of 7030KHz when powered by 12V, but this dropped to an encouraging 5-10mW at 3.6V (3 x 1.2V NiMH cells in series).
For the final version, I wanted all the electronics to be on one single board. At that point, I was thinking about purchasing a PicoKeyer chip from N0XAS and building the keyer, Manhattan-style onto the same board as a Manhattan-built transmitter. Then I remembered the Hans Summers QRSS Transmitter that I had built a few years ago. After a brief flirtation and a lot of fun with QRSS on 30M, the board sat languishing in a box.

Project info at AA7EE site.

Check out the video after the break. Continue reading “The Sproutie “SPT” Beacon – A legal, unlicensed HiFER beacon”

ESP8266 MQTT client on RTOS

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Baoshi wrote a MQTT client for Espressif’s RTOS SDK:

If you search MQTT and ESP8266 on the intraweb, most likely all hits can be traced back to the great work done by TuanPM. However Tuan’s code is based on Espressif’s NON-OS SDK. There has been some great debates about embedded programming with-or-without an OS. To me programming with OS vs NON-OS is like programming with C vs Assembly. I like programming in C, so I wrote a new MQTT client for Espressif’s RTOS SDK.

The source code is available at Github.

#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.