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: Aluminum electrolytic capacitors design for long operational life

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App note from KEMET on long life electrolytic capacitors. Link here (PDF)

The service life for high quality power supplies and automotive power electronics is often limited by electrolytic capacitors’ operational life (Lop). Very long life (> 20 years at temperature up to 75C) is possible to be achieved by choosing capacitors with optimized design. Type of electrolyte, capacitors lid design, sealing method and rubber material quality, are important factors which determine the Lop.

App note: Comparison of ceramic and tantalum capacitors

 

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App note from KEMET about the replaceability between ceramic and tantalum capacitors to each other. Link here (PDF)

Ceramic capacitors have a multitude of dielectric types available and each of these types is characterized by their sensitivities to temparature, but not to voltage or time. This paper compares the X7R, X6S, or X5R dielectric types of ceramic capacitors with tantalum capacitors. Ceramic capacitors constructed witht these dielectrics offer moderate dielectric constants with moderate temperature and voltage sensitivities. They overlap with tantalum capacitors in capacitance/voltage range offerings. In many cases, the solder pad geometry allows swapping of ceramic 0603. 0805, 1206 or 1210 chip sizes with “J”, “R”, “A”, or “B” case tantalums, respectively.

Video tutorials: Building the Arduino based data loggers

From the comments on our Arduino data logger post:

A visiting researcher dropped by our humble basement workshop with questions about the physical skill level students would need if they added one of our DIY data loggers to their environmental curriculum. I figured the easiest way to cover that was to simply build one, while they recorded the process.
The result of that 3 hour session is now available on YouTube

Thanks Edward Mallon!

Project info at the Cave Pearl Project website.

STM32F103 vs GD32F103 round 4: SPI master

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Sjaak writes, “This is part 4 in the series where we compare the STM32F103 with its Chinese counterpart the GD32F103. Both are ARM Cortex M3 microcontrollers which are mostly pin, peripheral and register compatible. Now we compare the SPI master peripheral of both chips.”

More details at smdprutser.nl.

Check out the video after the break.  Continue reading “STM32F103 vs GD32F103 round 4: SPI master”

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”

Building a GBA LiPo voltage regulator and charger

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Alex published a new build:

I saw a post where someone fitted a 2000mAh LiPo battery to their GBA, they had do to some modifications to the GBA battery compartment to fit it all. By using a LiPo battery instead of the AA’s, it would save us about 20 grams, while not a lot, ever gram does count and you can tell the difference plus since the LiPo has a higher voltage, it has a higher energy density, so it should give us longer play time than the AA’s. So I decided I would do the same mod and I might make a little voltage regulator and charging board to go along with it.

See the full post on insideGadgets project page.

A software only solution to the vexing Beagle Bone Black PHY issue

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Josh Levine has a nice write-up about a software only workaround for the Beagle Bone Black PHY issue:

Sometimes the Ethernet port on a Beagle Bone Black does not work on power up. It takes either a physical reset button press or a power cycle to fix it. This problem affects all BBB’s and until now could only be solved with hardware hacks.

The final official word from TI on this problem:
“There is no solution for this on the BB Black“

Full details at josh.com.

Tutorial: Setting up a low cost QRP (FT8, JT9, WSPR etc) monitoring station with an RTL-SDR v3 and Raspberry pi 3

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A detailed tutorial on how to set up a cheap QRP monitoring station using an RTL-SDR V3 and a Raspberry Pi 3 from rtl-sdr.com

This tutorial is inspired by dg0opk’s videos and blog post on monitoring QRP with single board computers. We’ll show you how to set up a super cheap QRP monitoring station using an RTL-SDR V3 and a Raspberry Pi 3. The total cost should be about US $56 ($21 for the RTL-SDR V3, and $35 for the Pi 3).
With this setup you’ll be able to continuously monitor multiple modes within the same band simultaneously (e.g. monitor 20 meter FT8, JT65+JT9 and WSPR all on one dongle at the same time). The method for creating multiple channels in Linux may also be useful for other applications. If you happen to have an upconverter or a better SDR to dedicate to monitoring such as an SDRplay or an Airspy HF+, then this can substitute for the RTL-SDR V3 as well.

More details at rtl-sdr.com.

Sega System 16 security reverse engineering

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Reverse engineering of Sega’s System 16 Hitachi FD1089 cpu security module by Eduardo Cruz:

I’m glad to announce the successful reverse engineering of Sega’s System 16 cpu security modules. This development will enable collectors worldwide preserving hardware unmodified, and stop the general discarding of Hitachi FD modules.
The project is right now involving external testers so expect further details and full disclosure over the coming weeks.

Further details on Arcade Hacker blog.

Check out the video after the break. Continue reading “Sega System 16 security reverse engineering”

#FreePCB via Twitter to 2 random RTs

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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.

Neopixel clock, v2

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David Zweben published a project writeup showing how he built a Neopixel clock powered by an Arduino Pro Mini clone and a real time clock module:

After building my first Neopixel Clock, I decided I needed one for myself. There was no way I was going to solder 90 lengths of wire onto 180 tiny pads again, though, so I knew I needed to design a custom PCB. This necessitated a redesign of the entire clock, focused around making it as easy as possible to assemble.

Project info at zweben.org.

Check out the video after the break. Continue reading “Neopixel clock, v2”

Game of Life on a Raspberry Pi (and a LED board) in Haskell

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Trandi published a Game of Life on a Raspberry Pi in Haskell project, that is available on Github:

This is a quick post about, re-purposing my Raspberry Pi + Peggy2 art installation, which already re-purposes a 8-9 years old Peggy2 LED board, to play Conway’s Game of Life.

Trandi’s Peggy2 board has been through several lives at this point. Past iterations have displayed weather data, cryptocurrency tickers, best bitcoin sportsbooks odds, and various generative art patterns before landing on Conway’s cellular automata. The Haskell implementation is a natural fit for the functional logic the Game of Life demands.

More details on Robotics /Electronics /Physical Computing blog.

Check out the video after the break. Continue reading “Game of Life on a Raspberry Pi (and a LED board) in Haskell”

Free PCB Sunday: Pick your PCB

BP-600x373

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: Trends in integrated circuits that affect ESD protection requirements

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A quick lookup on the ESD protection evolution of ICs in this app note from ON Semiconductor. Link here (PDF)

The stunning progress in integrated circuit capability over the last 40 years is most succinctly expressed by Moore’s Law; “Every 2 years the number of transistors that can be economically manufactured in an integrated circuit will double”. The secret to this success has been the shrinking of integrated circuit feature sizes in all three dimensions. To maintain circuit reliability with the smaller dimensions the operating voltage of integrated circuits has been steadily declining. This trend will continue in the future, as documented in the International Technology Roadmap for Semiconductors. As the working voltage for integrated circuits decreases the voltage at which circuit damage can occur also decreases.

The move to smaller geometries has also prompted fundamental changes in IC technologies that have had an adverse effect on the intrinsic ability of the technologies to survive ESD stress. A prime example is the evolution of nMOS transistors in CMOS technologies.

App note: Circuit configuration options for TVS diodes

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Different TVS configuration usage app note from ON Semiconductor. Link here (PDF)

Transient Voltage Suppression (TVS) protection is important because EMI and ESD can disturb the operation of the system, produce permanent damage or cause latent damage that will eventually cause a failure. Avalanche TVS diodes and diode arrays are available in a number of different circuit configurations to protect electronic circuits from surge voltages. This document will analyze the attributes and trade-offs of different circuit configurations created with avalanche TVS and diode array protection devices.

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”

Emulating a hardware ROM in real time with an STM32F4

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ROM emulation using an STM32F4:

I remember reading dhole’s  Emulating a GameBoy Cartridge with an STM32F4 some time ago thinking that it had a lot of applications with respect to old computers. In that article  a STM32F4 microcontroller  ‘pretends to be a ROM chip for a gameboy’. At the start of a bus cycle, an interrupt is triggered in the STM32F4, it then reads the address bus of the gameboy’s 6502, checks the gameboy’s read/write line(s) and pulls data from its internal Flash and presents it onto the data bus long enough for the gameboy to read it, then tristates the databus. There are no wait states. It does this all within the 1000ns of the 1MHz Gameboy CPU clock. For all intensive purposes the gameboy thinks it has a real rom chip attached.

Full details at Kernelcrash.com .

Bit-bang FTDI USB-to-serial converters to drive SPI devices

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Scott W Harden writes , “The FT232 USB-to-serial converter is one of the most commonly-used methods of adding USB functionality to small projects, but recently I found that these chips are capable of sending more than just serial signals. With some creative programming, individual output pins can be big-banged to emulate a clock, data, and chip select line to control SPI devices.
This post shares some of the techniques I use to bit-bang SPI with FTDI devices, and some of perks (and quirks) of using FTDI chips to bit-bang data from a USB port. ”

See the full post on Scott Harden’s blog .

Check out the video after the break Continue reading “Bit-bang FTDI USB-to-serial converters to drive SPI devices”