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How to build your Energy Load manager

พฤ, 09/13/2018 - 06:54

A detailed instructions of how to build an Energy Load manager from Open Electronics:

When the instantaneous power consumption exceeds the set values, it selectively disconnects the users, in order to prevent the electric meter to cut the power to disconnect.
The management of the electricity users at home, intended as the possibility to define the operating priorities and to momentarily disconnect the ones that may be “sacrificed”, is something that has become important since the coming of the electronic meters. With respect to the traditional ones, such meters are in fact a bit less tolerant towards the overloads, and they could suddenly leave us without power. Given that nowadays the electric meter is almost always outside and that in order to rearm it we should get out of the house; not to mention that the disconnection will probably turn off the computer that is sending files via the Internet, or that a user might not be able to shut down. In order to prevent such a situation, we created the load manager: in the previous installment, we described its hardware. It is now the moment to deal with the software governing it, and with the management of its functioning via the user interface.

Project info at open-electronics.org.

Rescuing the Defcon badge with the Bus Pirate

พฤ, 09/13/2018 - 05:33

Brandon Vandegrift @bmv437 tweeted, “Got my @defcon badge working again! I must have shorted out either R9 or R10, which are pull-up resistors for the I2C data lines. Without that, the PIC32 can’t communicate with the LED driver board. @dangerousproto Bus Pirate to the rescue, with it’s built in pull-up resistors!”

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

#FreePCB via Twitter to 2 random RTs

พุธ, 09/12/2018 - 01:50

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.

Updated Bus Pirate v3.x concept design

อังคาร, 09/11/2018 - 20:32

 

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.

Build a Multisensor Shield for ESP8266

อังคาร, 09/11/2018 - 05:17

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.

Tool battery teardowns: Craftsman 19.2V and Ridgid 12V

อังคาร, 09/11/2018 - 04:25

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.

Free PCB Sunday: Pick your PCB

จันทร์, 09/10/2018 - 02:59

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: The reduction of input voltage spike on power switches

จันทร์, 09/10/2018 - 00:00

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.

App note: Analyzing VIN overstress in power ICs

อาทิตย์, 09/09/2018 - 20:00

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.

Free PCB coupon via Facebook to 2 random commenters

เสาร์, 09/08/2018 - 05:32

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.

Electric steam boiler – first steam

พฤ, 09/06/2018 - 04:38

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.

#FreePCB via Twitter to 2 random RTs

พุธ, 09/05/2018 - 06:33

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.

Lattice iCE40 Ultra Plus FPGA: Gnarly Grey Upduino – Tutorial 1: The basics

พุธ, 09/05/2018 - 06:29

A how-to getting an LED flashing using VHDL from Harris’ Electronics:

The cheap price however comes with a few niggles, namely getting it up and running in the first place with the limited documentation. Gnarly Grey do a great job of explaining programming a starting program but don’t say much about further development. With that in mind, I’m going to run through the methodology of getting an LED flashing using VHDL. There seem to be a fair few Verilog methods but not many people seem to have touched upon VHDL with these FPGAs.

See full post here.

Free PCB Sunday: Pick your PCB

จันทร์, 09/03/2018 - 04:46

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: DC/DC converter testing with fast load transient

จันทร์, 09/03/2018 - 00:00

Another app note from Richtek, this time about transient load testing on power converters and how you can make a simple and low cost fast transient tool. Link here (PDF)

Load transient testing is a quick way to check power converter behavior on several aspects: It will show the converter regulation speed and can highlight loop stability problems. Other power converter aspects like input voltage stability, slope compensation issues and layout problems can be quickly spotted as well. This application note will explain the practical use of load transient testing to diagnose DC/DC power converter problems.

App note: RT2875 3A automotive buck converter

อาทิตย์, 09/02/2018 - 20:00

An application note from Richtek on buck converter used in automotive application. Link here (PDF)

Automotive environment can be quite harsh and designing electronics that need to work reliable in this environment takes special care, and often requires automotive qualified parts.

When designing voltage regulators that need to step down an intermediate voltage from the car battery supply, the car battery voltage fluctuation needs to be taken into regard.

The full operating temperature range needs to be considered for all aspects of the design, and all component parameters have to be checked over temperature.

The car radio receiver is nearby, which means that any switch-mode converter radiated emission needs to be minimized to avoid switch noise being coupled into the car radio receiver.

Free PCB coupon via Facebook to 2 random commenters

เสาร์, 09/01/2018 - 06:29

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.

Big Timer

เสาร์, 09/01/2018 - 06:04

Peter Scargill  has a nice write-up about a powerful timing node for Node-Red, the Big timer:

Big Timer is (probably) the best-ever timing node for Node-Red, providing a general purpose timer as well as  handling summer/winter correctly as well as (importantly) lighting up time (for which you should provide longitude and latitude). After all you probably don’t turn the outside lights on at 6pm!! You turn them on when it gets DARK.

Project info on Scargill’s Tech blog.

Tutorial: Using the Arduino’s internal EEprom to store calibration data and LCD screen fonts

พุธ, 08/29/2018 - 06:06

Edward Mallon writes:

This is a follow-up to our post about using Nokia 5110 screens on three unused analog lines with shift-out. That saved me from messing with the hardware SPI bus which we reserve for the SD cards. A secondary benefit is that the code is really lean, on the order of about 250 bytes for the default font after the compile if you already have EEprom.h in the build anyway. The font, however takes up about 500 bytes, and I wanted the smallest possible footprint so that we could add live data output to loggers that are already compile near the memory limits. As it turns out, stuffing those fonts into the internal EEprom was pretty easy to do:
Using the Arduino’s Internal EEprom to Store Calibration Data & LCD Screen Fonts

More details on Underwater Arduino Data Loggers blog.

Via the comments.

#FreePCB via Twitter to 2 random RTs

พุธ, 08/29/2018 - 03:53

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.