#FreePCB via Twitter to 2 random RTs


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.

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Updated Bus Pirate v3.x concept design



Development on DirtyPCBs.com is winding down, so I’ve had some time to play with hardware. I’ve said the same thing for a few years now, but this time it really happened!

This update of Bus Pirate v3.x crams in a major new feature, and slightly lowers the total cost. Two China-sourced analog switches enable pull-up resistor voltage selection – 3.3volts, 5volts, or External – directly from the terminal menu. A new IO header is compatible with fancy tangle-free silicone wire probe cables. An updated USB to serial converter chip reduces the BOM to offset the cost of the new features.

Pull-up voltage select 3.3v/5v/Vpu pin

Bus Pirate v3.x has on-board pull-up resistors for 1Wire, I2C, and any other situation where an open drain bus is used. Currently the pull-up resistors are fed through the Vpull-up pin (Vpu). In almost all cases I use a wire to connect the Vpu pin to the on-board 3.3volt or 5volt power supply.


It would be so much more convenient to select one of the on-board power supplies from the Bus Pirate menu, instead of connecting an extra wire to the Vpu pin. The v4 hardware made an attempt at this, but with a circuit that creates a lot of voltage drop.


I spotted the BL1551 analog switch while browsing Chinese chip datasheets at JLC. BL1551 is a $0.04 analog switch with low on-resistance (2.7ohm at 5.0volts) and high current capacity. It seemed like a good candidate for switching the pull-up resistor source.


Two BL1551 are chained together so that three input sources (3.3volt, 5volt, Vpu pin) are controlled by two pins. All the PIC microcontroller pins are already used, but a little hack lets the hardware version ID pins drive the BL1551.

1 x 10pin keyed locking connector, corrected pinout


Bus Pirate v3.x has always used a 2x5pin IDC connector. These are super common and easy to use with 0.1” jumper wires from the parts box. Unfortunately there aren’t many good cable options for an IDC connector, a probe cable made from ribbon wire always feels cheap. I rolled a few versions with various JST connectors, but a custom cable makes everything less handy.

Eventually I settled on a 1x10pin 2543/TJC8S-10AW connector (equivalent to Molex 70553-0044), a common 0.1” pin header inside a keyed/locking shroud. Jumper wires still work great because the pins are 0.1” pitch, but now we can make high quality keyed/locking probe cables with tangle-free silicone wire.

The pinout on the new connector is corrected to MOSI-CLOCK-MISO-AUX-ADC-Vext-3.3V-5V-GND. The original v3.x pinout was mangled in early revisions, and the current mess has been grandfathered-in since the first production run.

FT230X USB to serial converter


The FT232RL has been the go-to USB-to-serial converter chip for a decade (IC2, left). It’s used on the Bus Pirate v3.x, as well as oh-so-many Arduinos. FT230X is a new version that uses the same FTDI drivers everyone already has installed, but it’s half the price and comes in a smaller package (IC4, right).

Moving to the FT230X frees up board space for some PCB tweaks, and reduces the BOM cost by about $2 in single quantity.

USB Micro B

What kind of USB cables do you have laying around these days? I’ve got a ton of USB Micro B cables from phones and phone chargers, and those are slowly being replaced by USB C cables. The Mini B connector on v3.x is a relic.

My updated board uses a USB Micro B connector. It’s not hand-solder-hobby-friendly like the USB Mini B connector. To be completely honest, every hand-soldered prototype connector eventually broke off the board, often lifting traces with it. There are two versions of this hardware in git – one with a generic Chinese USB connector, and one using an expensive Molex connector with through-hole reinforcement.

5cmx5cm PCB size


Swapping the IO connector and USB chip made it possible to fit everything on a 5cmx5cm PCB. This version fits on the super cheap 5x5cm PCB prototype packs sold at most board houses.

Taking it further

This Bus Pirate has been on my bench for about six months, and it’s hard to go back to an older version. Selecting the pull-up voltage from the terminal is really convenient. The IO header pinout makes a lot more sense, and the cable options are pretty sweet. The Micro B connector may be the best update, now the Bus Pirate works with the phone cables I always have around.

The Eagle schematic and PCB files are in git. The hardware is significantly different from v3.x and needs a custom firmware build, so I called it v5. The version isn’t set in stone. There is also a firmware branch with support for the new hardware.

There are no plans to produce this version of the board without lots more testing and community feedback. PCBs for the Molex USB version should be available in the free PCB drawer in a few days.

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Build a Multisensor Shield for ESP8266


Rui Santos has a great write-up on building a Multisensor Shield for ESP8266, that is available on GitHub:

In this project you’ll discover how to design and create a Multisensor Shield for the ESP8266 Wemos D1 Mini board. The shield has temperature sensor (DS18B20), a PIR motion sensor, an LDR, and a terminal to connect a relay module. We’ll start by preparing all the hardware and then program it.

See the full post on Random Nerd Tutorials blog.

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Tool battery teardowns: Craftsman 19.2V and Ridgid 12V


Russell Graves did teardown of a Craftsman 19.2V DieHard battery and a Ridgid 12V battery:

It’s time for more tool battery teardowns!  This week, I’ve got a Craftsman 19.2V DieHard battery, and a cute little Ridgid 12V battery.  They’re both lithium, and I’m going to dig into both of them, because that’s what I do with old batteries I pick up out of junk bins.
If you’re bored of tool battery teardowns, you could always send me more interesting things to mess with!  I enjoy poking around tool batteries, and a lot of the ones I pull apart are “new to the internet” in that they haven’t had a detailed teardown before.   It’s always interesting to see how different companies approach much the same problem.

More details on Syonyk’s Project blog.

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Lenguaje inclusivo en redes sociales (de marcas)

Usuarixs, usuari@s y usuarios

La ortografía y las redes sociales nunca han sido lo que se dice mejores amigas. En los últimos años muchas personas se han unido a la guerrilla ortográfica de internet, señalando cada b o v mal puesta en Twitter; pero la mayoría sigue haciendo más o menos lo que le da la gana. Y muy bien que hacen.

Por eso, si alguien ha dejado internet durante los últimos dos años (no le culpamos), probablemente no le sorprenda a su vuelta que haya un montón de gente joven escribiendo ‘chic@s’, ‘amigues’ o ‘trabajadorxs’. Será una de esas modas ortográficas, como las maYúsCuLaS iNteRcalADas, ¿no? Pero en el momento en que vea que personas ya con canas e incluso empresas reconocidas están hablando así de raro, comenzará a pensar que aquí está pasando algo.

⬆ Aunque se las tape, Raphael es uno de eso señores con canas ⬆

¿Qué es es eso del lenguaje inclusivo?

Pues sí, aquí pasa algo: esas personas/organizaciones están utilizando lenguaje inclusivo. Dirán que bueno, eso no deja de ser también una moda ortográfica progre, ¿no? La realidad es que el lenguaje inclusivo es una forma de reivindicar la igualdad de género a través del lenguaje, incluyendo en él también a la población femenina para no invisibilizarla. Puede que sea una moda, sí, pero ahora mismo es trending topic en el mundo online.

Es un recurso bastante sencillo de entender, identificar y usar. Consiste en sustituir o transformar las palabras sensibles de excluir a las mujeres, en otras que las incluyen. Esto se puede hacer de diferentes formas, tanto en el lenguaje oral como el escrito:

  • Sustitución por una expresión inclusiva. Hola a todos -> Hola a todo el mundo
  • Duplicación del género de la palabra. Hola a todos -> Hola a todos y a todas
  • Transformación con un símbolo. Hola a todos -> Hola a tod@s / Hola a todxs / Hola a todes

¿Eso se puede hacer?

Algunas de estas formas no son correctas a ojos de la R.A.E, pues “el uso genérico del masculino” se supone que es suficiente para incluir a ambos géneros. Las personas que defienden el uso del lenguaje inclusivo defienden que no es suficiente, y consideran más importante esta forma de luchar por la igualdad de género que las normas de una entidad que, al fin y al cabo, no es dueña de la lengua castellana.

¿Qué pintan aquí las marcas?

Si hay algo en lo que podemos estar de acuerdo es en que la sociedad está cambiando muchísimo, y la mayoría de empresas se están intentando adaptar (como pueden) a esa transformación. En este nuevo paradigma, “las marcas están pasando de ser entes asépticos y objetivos a expresar claramente su filosofía, sus valores, sus actuaciones y su contribución con el progreso social” (Hermanos Rodrigo Martín). En la España de 2018, referente mundial en cuanto a concienciación frente a la desigualdad de género, ¿qué marca no cuenta con la igualdad entre los valores que defiende?

En este mundo interconectado, en el que las compañías están más expuestas que nunca, todo lo que hace o dice una marca comunica sus valores. Y por eso se deben empezar a preguntar por el lenguaje inclusivo: porque lo que hagan o dejen de hacer al respecto va a determinar el mensaje que mandan a la sociedad.

Algunas han movido ficha, empezando a utilizarlo en sus redes sociales. Siguen siendo una pequeña minoría, y a veces se encuentran con una parte de su público no muy contento con esos mensajes, pero es una tendencia a observar.

¿Y qué debo hacer yo?

Puede que esto se quede en una moda ortográfica, como bromeábamos al principio. También es posible que, como tanto han cambiado las marcas en los últimos años, también en esto se transformen todas, y las redes del mañana estén llenas de equis y arrobas por una buena causa. Desde luego, desde 40deFiebre no vamos a decir a nadie cómo tiene que pensar o hablar.

Lo que sí podemos afirmar es que lo mejor para una marca es decidir qué quiere comunicar en sus redes y cómo hacerlo, valorando si utilizar o no este tipo de lenguaje.

Así que lo dicho: ¡adiós a… todo el mundo!

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Free PCB Sunday: Pick your PCB


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.

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App note: The reduction of input voltage spike on power switches


Another app note from Richtek introducing solutions for reducing the input voltage spike on power switches. Link here

The power switch is a low voltage, single N-Channel MOSFET high-side power switch, optimized for self-powered and bus- powered Universal Serial Bus (USB) applications.

In worse operating condition, an input voltage spike may over the chip’s maximum input voltage specification to damage the chip.

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App note: Analyzing VIN overstress in power ICs


Investigative app note from Richtek about the component failure point caused by EOS. Link here (PDF)

Failures in power ICs are often the result of Electrical Over Stress (EOS) on the IC input supply pin. This report explains the structure of power IC input ESD protection and how ESD cells can become damaged due to EOS. Common causes for input EOS are hot-plug events and other transient effects involving wire or trace inductance in combination with low ESR ceramic capacitors. Solutions are presented how to avoid EOS via special circuit and system design considerations.

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Free PCB coupon via Facebook to 2 random commenters


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.

from Dangerous Prototypes https://ift.tt/2x11h0v

Electric steam boiler – first steam


Quinn Dunki has a great write-up on building this homemade-from-scratch electric steam boiler:

Yes, you read that title correctly. After many months of effort, this homemade-from-scratch electric steam boiler is finally going to make steam. Before we’re done, we’ll learn some sobering lessons about the dangers of live steam.
Now that our boiler is pressure-tested and all the accessories are hooked up, we’re ready to add heat to water and cause some trouble. Unlike a traditional fired boiler which would use fuel pellets, coal, wood, or some other combustible, this crazy contraption is “fired” with an electric immersion heating element built into the structure. In order to test making steam, we need to rig up the electrical bits.

Project info on BlondiHacks blog.

Check out the video after the break.

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