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ถูกปรับปรุง 1 ชั่วโมง 29 min ก่อน

Free PCB Sunday: Pick your PCB

5 hours 26 secก่อน

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: HT66FB574 single colour independent light streamer USB keyboard

10 hours 47 minก่อน

Another app note from Holtek this time about their HT66FB574, a USB keyboard device that can support single color LED streamer. Link here (PDF)

The video gaming industry is seeing continual increasing demand for multi-feature keyboards. These can include features such as keys with an individual LED which can display different graphical effects along with variable illumination levels. With each key having an illuminated surrounding area effect along with multiple colour and pattern changes, this allows for a more colourful and stimulating gaming keyboard.

App note: HT66FB574/572 colour effect USB mouse

อาทิตย์, 10/21/2018 - 20:00

App note from Holtek on using their HT66FB574/572 to develop color effect mice. Link here (PDF)

Demands from the video gaming industry for different types of gaming mouse continue to expand. Adding a large number of RGB LEDs to the mice can produce different colours and brightness changes creating a range of visual special effects. This enhances the colour and stimulating effects of gaming mice. For example, having multiple RGB LEDs to form an outer ring on a gaming mouse can produce a colour changing waterflow effect. These are known as colour effect USB mice.

The USB-C Explorer

เสาร์, 10/20/2018 - 06:11

Jason has designed a development board for USB-C and Power Delivery, that is available on GitHub:

The USB-C Explorer is a development board with everything needed to start working with USB Type-C. It contains a USB-C port controller and Power Delivery PHY chip, a microcontroller, and several options for user interaction.

Project info on Reclaimer Labs blog. It’s also up on Tindie.

Free PCB coupon via Facebook to 2 random commenters

เสาร์, 10/20/2018 - 05:18

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook 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.

Tutorial: Git with Eclipse

เสาร์, 10/20/2018 - 05:10

A detailed tutorial on Eclipse with the EGit plugin by Erich Styger:

There are things which are game changer in the world of software development: one such event was when I started using a VCS (Version Control System): it changed for me how I keep and store my projects and settings. It even changed the way how I deal with non-software related items like documents or other valuable things: I started storing them in to a VCS too.

Via MCU on Eclipse.

Tutorial: Adding the SSD1306 OLED screen to an Arduino logger (without a library)

ศุกร์, 10/19/2018 - 05:09

Edward Mallon writes:

While I loved the Nokia 5110 LCD’s readability in full sun, the pressure sensitivity was a real problem for the underwater units. So I started noodling around with some cheap OLED screens from eBay.
With the exception of the init & XY functions (which are more complicated on the 1306 controller) the rest of the code ported over from the Nokia screen with no changes at all.  My guess at this point is that the shift-out method will work with most of the other cheap OLED screens, provided they don’t exceed the pin current limits implied by my method.

More details on Underwater Arduino Data Loggers blog.

SmileyBox – Statistics, the old fashioned way, upgraded

พฤ, 10/18/2018 - 06:25

Vagrearg published a new build:

Lies, damn lies and statistics.
You have a high school science fair and want to know how your project was perceived by the visitors. Modern online behaviour will direct you to “taking the online survey”. That requires an extra step for the visitors, usually by taking hold of their mobile device and fiddling with a small screen.
One problem you will encounter is designing good computer interaction and a proper look and feel on the tiny screen. It is a lot of work. A second problem is the distraction of using the mobile device with respect to the project being surveyed. The visitor will concentrate on the mobile device and that will diminish focus on the project for a moment. A third problem is anonymity and proliferation of data. Do we really need to be online and spread all that information one’s device sends?

Project info at vagrearg.org.

Automated channel switching with Motorola GM3x0

พุธ, 10/17/2018 - 06:47

Florian Wolters wrote an article on automated channel switching for POCSAG/DAPNET transmissions on MMDVM system:

With the integration of POCSAG/DAPNET features into the MMDVM/MMDVMHost I came to think about if it would be possible to combine an MMDVM repeater/HotSpot with a DAPNET tranmitter. The advantage in Germany is that there is a single coordinated frequency for POCSAG tranmissions on UHF. 439.9875MHz is used for fixed-frequency pagers which are modified to receive on that frequency. With latest hand-programmable pagers (e.g. AlphaPoc) it would basically be possible to set them to the repeater frequency but that wouldn’t work while one is en route.
In the programming software for Motorola GM3x0 radios I found an interesting GPIO setting called “Channel Steering”. Some line of the help function revealed that it would exactly do what I expected. You can trigger a GPIO and the radio switches channels.

Via Notizbl0g.

Check out the video after the break.

#FreePCB via Twitter to 2 random RTs

พุธ, 10/17/2018 - 05:04

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.

Shenzhen to Hong Kong on High Speed Rail

อังคาร, 10/16/2018 - 15:22

Even though Shenzhen and Hong Kong are basically the same city on opposite sides of a border, it’s still a frustratingly long trip to Hong Kong Central for a Reuben at Morty’s Deli. The new high speed rail line linking downtown Shenzhen to downtown Hong Kong makes the trip in just 15 minutes. A lot of frequent travelers are hoping it just got a lot easier to eat delicious pastrami on a whim, but with all the formalities of Chinese rail will it really cut the travel time? We jumped on to find out!

Futian Railway Station is two metro stops from the Huaqiangbei electronics market, in the Futian Central Business District. It’s always empty, despite being several years old and absolutely massive. Unlike most Chinese rail stations, it’s actually in the middle of the city.

It usually takes less than 10 minutes to collect tickets and go through the security checks. Shenzhen North station is on the same high speed rail line, but it’s so busy that it often takes more than an hour to get into the station. Foreigners can’t use the ticket vending machines, so we had to go to the window and hand over our passports to buy tickets from a human.

Security checks make Chinese high speed rail more like flying out of an airport. Identity check, baggage x-ray, metal detector, and finally a manual pat-down. This is where Futian station really shines – it’s so empty that security takes less than a minute. Security in Shenzhen North can take 30 minutes or more.

Everyone riding the train was super excited. It was the same atmosphere as when the A380 was a new and exciting airplane to ride. Lots of pictures and selfies.

This train has the Hong Kong MTR logo on the side, and seems to serve only Futian and Kong Kong stations. There were no other passengers on the train from stations further north when we boarded.

Second class tickets are around $9, first class is around $15. About the same price as taking the metro.

This is the first class cabin. Some trains also have a tourist class or business class with lay-flat seats, but at $50 it seems a bit too posh for a 15 minute train ride.

Maximum speed was around 180 km/h. The entire trip is in an underground tunnel so there’s not much to see. The WIFI didn’t seem to work, but there was 4G mobile data during the whole ride.

In Hong Kong there’s a joint border crossing for both Hong Kong and China. After getting off the train you go through immigration to leave China, walk a bit, then show your passport to get into Hong Kong. Chinese immigration does a customs check on the way out, every bag of any size has to go through an x-ray machine.

Kowloon West Station is magnificent, but also a bit of a chaotic mess. It’s also not really anywhere useful, it’s a ten minute walk through malls to find a metro to Hong Kong Central.

Returning to Shenzhen is much less convenient. The line to purchase tickets is super long, like the line for the Hong Kong Airport McDonald’s. The line to pickup tickets purchased via apps is more reasonable, like the line for the Hong Kong Airport Popeye’s. As in China, foreigners can’t buy tickets at the vending machines. After seeing this mess we decided it would be faster and more pleasant to catch the metro back instead.

Takeaways

From our door to Morty’s Deli in Central usually takes about 1 hour and 45 minutes using a cross border bus or the metro. It took about 1 hour and 15 minutes using high speed rail. A half hour faster isn’t bad, but it also takes a lot of planning. Tickets need to be purchased in advance, timing at the station needs to be just right, and West Kowloon isn’t exactly a useful location in Hong Kong.

Coming back to Shenzhen from Hong Kong seems like it could take even longer than a bus or metro. There’s huge crowds picking up tickets for destinations all over mainland China, so ticket collection takes forever. That means arriving early to get the tickets, then extra waiting around for a scheduled train. It’s so much easier to step onto the next metro back to Shenzhen and enjoy the ride.

Even if high speed rail is consistently faster, the experience of doing it requires all the focus and planning of catching a flight at an airport. We’ll take it from Shenzhen Futian to Hong Kong in the future, but with so much planning involved it’s always going to be easier to take the metro back.

Yet another Masterplay clone

อังคาร, 10/16/2018 - 06:46

Dr. Scott M. Baker made a Masterplay clone:

The Masterplay was originally a device that allowed Atari 2600 digital joysticks to be used with the Atari 5200. In this post, I describe a masterplay clone that I created.
The analog controllers for the Atari 5200 are (in)famous for their poor feel and performance. The analog stick, while a really good idea at the time, doesn’t have a decent return-to-center feature. As the vast majority of the games for the 5200 do not make use of the analog capability, this feature while innovative, is far more of a drawback than a benefit. As such, there have grown to be a number of different solutions for connecting Atari 2600 sticks to the 5200.

See the full post on Dr. Scott M. Baker blog.

Free PCB Sunday: Pick your PCB

จันทร์, 10/15/2018 - 06:37

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: Power battery charger application guidelines

จันทร์, 10/15/2018 - 00:00

App note from Holtek on smart battery chargers. Link here (PDF)

Battery chargers usually are products which transfer alternating currents to low voltage direct currents and which are widely applied in various rechargeable battery application fields. According to different applications, battery chargers can be divided into two types, namely digital chargers and power battery chargers. In not having an MCU for charge management, traditional charger applications fail to implement precise control of the battery charging curve, which will result in situations such as overcharging or charging to less than full capacity, situations which will affect battery life.

Holtek provides MCUs dedicated for power battery charger applications. In addition to resolving the problems of poor control of the charging curve, these MCU devices also include a battery charging management module, which can precisely control the charging voltage and current. The devices therefore reduce the need for the usually required external operational amplifier and TL431 components in traditional battery charging circuits. The charging voltage and current calibration parameters and profiles can be stored into the MCU’s internal EEPROM, thereby eliminating the need for traditional manual calibration, thus improving production efficiency.

App note: I/O emulated UART baud rate calibration

อาทิตย์, 10/14/2018 - 20:00

Software/bitbang method of baud rate calibration for micro without built-in UART, App note from Holtek. Link here (PDF)

Not every HOLTEK MCU contains a Universal Asynchronous Receiver/Transmitter function, otherwise known as a UART. If this function is required, it can be emulated using software. However, the software accuracy will change according to the system frequency error. This application note will illustrate how to use a software method to calibrate the baud rate and how to avoid errors between the two communicating parties. It will also show how to readjust to the same transmission frequency of each other when transmission errors occur.

Taking the HT66F4540 as an example, this application note describes the UART baud rate calibration method.

Free PCB coupon via Facebook to 2 random commenters

เสาร์, 10/13/2018 - 06:53

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook 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.

ESP32 AM radio transmitter

เสาร์, 10/13/2018 - 06:45

A how-to on making a simple AM radio transmitter using the ESP32 microcontroller by Bitluni:

AM Radio transmissions are based on a carrier signal which is modulated by the audio signal. It’s a very basic principle but prone to noise from the environment. Using the ESP32 it is really simple to generate an analog signal using the built-in DACs. With the provided code here just a wire as an antenna has to be connected to the pin 25 of the ESP32. The transmission will end up on the AM frequency ~835kHz.

Via Bitluni’s Lab.

Check out the video after the break.

Project PITA: Build a mini mass deauther using Bettercap and a Raspberry Pi Zero W

เสาร์, 10/13/2018 - 05:44

evilsocket shared a how-to on making a mini WiFi deauthenticator using Bettercap and a Raspberry Pi Zero W:

A few days ago I started playing with some idea I had from a few weeks already, using a Raspberry Pi Zero W to make a mini WiFi deauthenticator: something in my pocket that periodically jumps on all the channels in the WiFi spectrum, collects information about the nearby access points and their connected clients and then sends a deauthentication packet to each one of them, resulting in some sort of WiFi jammer on the 802.11 level. As an interesting “side effect” of this jammer (the initial intent was purely for the lulz) is that the more it deauths, the higher the changes to also sniff WPA2 handshakes.

See the full post on Evilsocket blog.

#FreePCB via Twitter to 2 random RTs

พุธ, 10/10/2018 - 03:58

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.

Inside a two-quadrant power supply – Agilent 66312A teardown and experiment

อังคาร, 10/09/2018 - 21:43

Kerry Wong did a teardown of an Agilent 66312A dynamic measurement DC source:

Typically, a lab power supply can only operate within a single quadrant. Take a positive voltage power supply for example, it can only output or source current. If any attempt is made trying to sink current into the power supply by connecting a voltage source with a higher voltage than the output voltage of the power supply, the power supply would lose regulation since it cannot sink any current and thus is unable to bring down and regulate the voltage at its output terminals.
The Agilent 66312A dynamic measurement DC source however is a two-quadrant power supply, it not only can source up to 2A of current between 0 and 20V, but also can sink up to 1.2A or 60% of its rated output current as well. Although lacking some key functionality of a source measure unit (SMU), Agilent 66312A can nevertheless be used in similar situations where both current sourcing and sinking capabilities are needed.

More details on Kerry Wong’s blog.

Check out the video after the break.