Using #Twatch as ICelsius wireless bbq thermometer monitor

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Daniel use the #twatch as a monitor for his ICelsius wireless thermometer:

Finally I found a purpose for my twatch.
I use it as a monitor for my iclesius wireless thermometer.
So I wrote a quick and dirty python script which works as a relay between the icelsius and the twatch.
The icelsius periodically broadcast the measure data to the local network.
The python script listen to the local network and capture this packet ,and then transform the packet to a format which the twatch understand.

Via the forum.

App note: Reed switch operation

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Reed switches operation app note from Hermetic Switch Inc. (HSI). Link here (PDF)

A reed switch is activated by a magnetic !eld. It’s important to realize that there are numerous possibilities for a switch’s orientation within a given magnetic field.

The length of the magnet and the length of the reed switch both affect the magnetic field coupling. Removal of the switch lead material reduces the “magnetic antennae.” The magnetic coupling is reduced, the sensitivity is decreased, and the magnet must get closer to the reed switch to activate it. This is a general rule for a parallel mode of operation

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: Reed switch basics

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Application note from Hermetic Switch Inc. (HSI) on simple reed switches. Link here (PDF)

A reed switch consists of two or three metal reed contacts (blades) that are hermetically sealed inside a glass tube containing an inert atmosphere. Reed switches come in various sizes, magnetic sensitivities, high power capabilities, high voltage capability, contact configurations, and lead configurations.

 

App note: Design guidelines for ATtiny43U

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Here’s a design guidelines for ATtiny43U from Atmel, app note here (PDF!):

The integrated boost converter of ATtiny43U provides the microcontroller and peripherals with a fixed supply voltage, generated from an external supply of lower voltage. The boost converter is a switching type, step-up regulator that requires
some external components to be complete. This includes an external inductor, a diode and some bypass capacitors. The inductor is connected between the VBAT node and the LSW pin, and the Schottky diode between pins LSW and VCC. In addition, an input capacitor and external bypass capacitor from VCC to GND areusually required.

App note: Mixed signal microcontroller

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A mixed signal microcontroller application note (PDF!) from Texas Instruments:

The Texas Instruments MSP430 family of ultra-low-power microcontrollers consists of several devices featuring different sets of peripherals targeted for various applications. The architecture, combined with five low-power modes, is optimized to achieve extended battery life in portable measurement applications. The device features a powerful 16-bit RISC CPU, 16-bit registers, and constant generators that contribute to maximum code efficiency. The digitally controlled oscillator (DCO) allows wake-up from low-power modes to active mode in less than 1 µs.
The MSP430G2x21/G2x31 series is an ultra-low-power mixed signal microcontroller with a built-in 16-bit timer and ten I/O pins. The MSP430G2x31 family members have a 10-bit A/D converter and built-in communication capability using synchronous protocols (SPI or I2C). For configuration details, see Table 1. Typical applications include low-cost sensor systems that capture analog signals, convert them to digital values, and then process the data for display or for transmission to a host system.

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”

10A Variac Soft Starter

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Steve Gardner did a repair of a 10A Carroll & Meynell Variac and documented the whole process on his blog:

I recently purchased a used 10A Carroll & Meynell Variac from eBay for use in the lab, however the variac often caused the 32A B-curve MCB in the consumer unit to trip due to the high inrush current of the variac core. To prevent this from happening and to add a few additional features I created the soft start circuit outlined on this page.
The idea of the soft start circuit is to limit the inrush current whilst the variac core is first magnetising. There are many ways to achieve this and most involve adding some form of resistive element in series with the transformer to prevent the transformer appearing as a very low impedance to the mains AC supply.

The method used in this project was to use a high power resistor in series with the transformer to limit the current. Once the current has settled, the resistor is shorted out by a relay to then allow the full load current of the variac to be drawn from the mains.

More details at SDG Electronics.

Check out the video after the break. Continue reading “10A Variac Soft Starter”

Sjaak’s Hackershop is open \o/

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Sjaak has announced that his Hackershop page is now open!

Today is a super exciting day as my friend Ian Lesnet from Dangerousprototypes.com finally got around in rewriting his website (well some parts I guess :) ) He already published parts of the new site (new DirtyPCBS and DirtySLA) , but today he added Hackershops. This enables people, like me, to sell small quantities of DIY electronics to others worldwide. A big plus is that he (and his shop) is located in Shenzhen, China, which means access to very cheap worldwide shopping. He also takes care of Paypal handling, packaging and shipping the goods to you. As a bonus you can also combine shipping for other items from the Hackershop or goods and services from the Dangerous Prototypes store. Can you beat that, Tindie?!
Currently the Soldering iron controller is being packaged by my manufacturer and should be available anytime soon. I also ordered the breakable SMD protoboards which should go directly from the PCB fabhouse to the store.

More info at smdprutser.nl

Building a simplex repeater

Kenneth Finnegan writes, “In this installment of the “How to Build a Repeater” series, I explain the concept of a simplex repeater and how to assemble one out of an Argent Data ADS-SR1 and a Motorola Maxtrac. Thanks again to Argent Data for providing me with an ADS-SR1 to play with; it’s a fun little controller.”

More info at Kenneth’s blog.

CSI Premier 75W and Hakko 936 solder station teardowns

Todd Harrison did a teardown of the CSI Premier 75W and Hakko 936 solder station:

I did the teardown of the CSI 75W solder station as well as the Hakko 936. The Hakko of course had all analog circuits using operational amplifiers and potentiometers as well as a temperature sensor in the iron tip to signal back to a triac chip controller which would trigger the triac to push 24 V AC through the heater in the iron. The CSI 75W was all digitally controlled with an internal microcontroller which was reading the temp sense line and switching the triac on/off through an opto isolator IC. And because it had a microcontroller it was also able to have the programmable set points and programmable sleep and power off timers.

More details at ToddFun.com.

DP 2016: Live from China!

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Today Dangerous Prototypes is a legal Chinese company! 100% legit with import/export license, work permits, visas, and an office in Huaqiangbei (the world’s largest electronics market). It is likely the only Open Hardware centric WFOE (Wholly Foreign Owned Enterprise) in Shenzhen, and perhaps China. It took over a year to complete the process, and we highly recommend you NOT try it yourself.

Shenzhen really is a hacker’s paradise, you can source, build, and make nearly anything. Shenzhen Dangerous Prototypes Electronics Technology Limited  allows us to have an office in the market, and hire local and foreign hackers to design open hardware projects. No need for a 16 hour flight to visit our manufacturer, Seeed Studio is just across town. The new company will also host Hacker Camp Shenzhen, and can apply for the hellish “Authorized Authority” visa letters for participants who need them.

Look out for a bunch of posts on forming Hong Kong and Chinese online casino slots companies. We really wanted to live blog it, but the whole thing seemed so onerous we decided to keep it off the blog until it was 100% completed.

Supply chain hacking and mash-ups are a new hotness for 2016: visit a bunch of factories, get to know the process and supply chain, mix and match new projects harnessing the existing Chinese ecosystem. We’ve been visiting a couple factories a month and have a number of mash-ups coming.

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The Expressway v1 is our first completed mash-up project. Video and pictorials of our trips to the silicone compression molding factory are coming soon. Don’t ever let someone convince you a joke is so good you should spend two days along a dusty road outside a hot silicone factory in Dongguan… Sorry guys!

Pax Instruments has some great ideas about component packaging. We’re almost ready with the first unconventional component kit that might just rock your workbench and change your life. Or at least make you smile.

In 2015 we continued to refine Dirty PCBs, and a team of four worked for over a year to create the next version. The new site, code named “DangerCore”, will slowly replace this entire site. DangerCore is designed from scratch to support the Dirty PCBs concept: give open hardware hackers cheap automated interfaces to the Chinese supply chain.

DangerCore has been running over at dev.dangerousprotoypes.com for a few months now, and is finally getting stable enough to transition parts to the main site. The old Zencart-based Free PCB Store will be removed next week, and replaced with the dev shop. The blog and forum will get a new mobile-first responsive theme to match the dev shop by the end of the month too.

Have a PCB or 3D model you’d like to share or sell? Upload your design and put it in our shop. You set a flat fee and/or markup, get order notifications, and see your sales statistics in a handy dashboard. Its like the share page on Dirty PCBs, but way way better!

Have a bit of hardware to sell too? Create a new page and add your project to the store! Long time team member Sjaak will release his T12 soldering iron driver in the store soon.

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Neoden, makers of the small pick and place we reviewed a few years ago, installed their brand new model in our Huaqiangbei office and did a demonstration. The Neoden 4 has top and bottom vision, holds nearly 60 reels, and has the industry standard rail-based PCB feeder system used on fully automated lines. At $7,000 without accessories ($10,000 fully loaded) the cost is twice the TM220, but man that’s a ton of pick and place for only $7K. Videos of the machine, install, and demonstration coming soon!

Finally, Hacker Camp Shenzhen is coming! It will be the last weekend in March or the first weekend in April. Feel free to vote in the comments. Activities will be market tours and factory tours. Tickets will go up in the dev shop soon.

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A huge thank you to Seeed Studio who continue to make it so easy to sell projects. They’ve absolutely blown up in the last couple years. Eric built an amazing company, but he also brought open hardware to China and promoted Shenzhen to makers like us. Without Seeed we would not be here. A huge thank you also to FlyLin Consulting, who spent a year working with agents, banks, and the government to get the company running. It would have been impossible to form the company without FlyLin’s constant help.

Atmega16u2 virtual serial example using LUFA Library

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Shane of Wattnotions has published a new build, an Atmega16u2 virtual serial LUFA board:

What I wanted the LUFA library to do was pretty specific – the atmega16u2 should show up as a virtual serial port so that the computer can connect and read data from it like any other serial port. All of the other ways of communicating over USB eg HID etc wouldn’t do it. There was one example that came with LUFA that fit the bill – VirtualSerial. There were a few problems with getting this example to run on the atmega16u2 so I’ll document them and what the fix was.

More info at Wattnotions site.

DIY USB volume knob

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Markus Gritsch made a nice USB volume control knob for his computer:

After having been inspired by this Instructable [1] I also wanted to make a nice looking volume knob to attach to my computer.
It uses the TrinketHidCombo library [2], but on a Digispark board, to have one more I/O pin which I use to drive a WS2812 LED ring. The code to bit bang the LEDs was taken from one of Josh’s excellent articles on WS2812 LEDs [3]. I also experimented with other WS2812 libraries (NeoPixel, light_ws2812, FastLED), but they consumed either quite a lot of flash, or prevented the USB part from functioning.

Via the project log forum.

Check out the video after the break. Continue reading “DIY USB volume knob”

#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.

New Energia 17 release brings SensorTag, Red Bear CC3200 And F28069M support

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The Energia team announces the availability of version 0101E0017.  We wrote about it previously:

A new version of Energia has been released. This version fixes alot of bugs from the previous version and also adds support for the following:

  • Support for three new boards have been added added:

– CC2650 based SensorTag (MT)
– CC3200 based RedBearLab WiFi micro (MT and Standard)
– LAUNCHXL-F28069M (Standard)

  • CC3200prog has been enhanced to automatically reset the RedBearLab boards after upload
  • I2C has been moved to the new BoosterPack standard (pins 9 and 10). This allows I2C and SPI to operate concurrently
  • DSLite has been updated to the latest version. MSP432 and CC2650 use DSLite for upload. Other boards will follow in the next release
  • Mac OS X Energia package is now signed and no special action is needed for Mac Gatekeeper

Downloads are available for Linux, Mac OSX and Windows.

More details at 43oh.

A 3.6V LiFePO4 charger for under 50c

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Nerd Ralph built his own 3.6V LiFePO4 charger:

I like LiFePO4 batteries. They have a rather flat discharge at around 3.2V, which is ideal for powering 3.3V devices without a regulator. You can also use them in devices that take 2 standard AA cells by using a blank shunt in the 2nd battery slot since 2 fresh alkaline cells in series provide 3.2-3.3V. And since they are readily available in the 14x50mm AA size, you can use cheap AA holders for them in electronics projects.
When it comes to chargers, things can be a bit problematic. LiFePO4 batteries should be charged to 3.6V, rather than 4.2V like regular lithium-ion batteries. A good charger costs $10-$15, but charging at a high current will reduce the number of recharge cycles. The Soshine batteries I bought indicate on the label a standard charging current of 300mA to 3.6V. Rather than search for a charger to fit the bill, I decided to make one.

Project info at Nerd Ralph blog.

CEmu, an open source TI-84 Plus CE / TI-83 Premium CE calculator emulator

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Cemetechian MateoConLechuga and his team Jacobly, Adriweb, Lionel Debroux, Vogtinator have been working on a portable and open source TI-84 Plus CE/TI-83 Premium CE emulator – CEmu , that is available on Github:

Features

  • Portable emulation core written in C
  • Decent emulation accuracy yielding the ability to boot all of TI’s CE OS’s, browse around, execute self test successfully, and run programs
  • Portable GUI written in C++ using Qt (making it run on Windows, Mac OS X, Linux, Android, and iOS!
  • Docks/Tabs-based graphical UI (which you are able to customize)
  • Integrated setup wizard with ROM dumper for your calculator (there’s another one in TILP beta)
  • Simple debugger (read CPU registers, flags, ASIC state) and port monitor/writer
  • Animated (GIF) and still (PNG) screenshots

More info at Cemetech forum.

Reverse engineering the ARM1, ancestor of the iPhone’s processor

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Another great article from Ken Shirriff, this time on reverse engineering the ARM1:

Almost every smartphone uses a processor based on the ARM1 chip created in 1985. The Visual ARM1 simulator shows what happens inside the ARM1 chip as it runs; the result (below) is fascinating but mysterious.[1] In this article, I reverse engineer key parts of the chip and explain how they work, bridging the gap between the puzzling flashing lines in the simulator and what the chip is actually doing. I describethe overall structure of the chip and then descend to the individual transistors, showing how they are built out of silicon and work together to store and process data. After reading this article, you can look at the chip’s circuits and understand the data they store.

More details at Ken Shirriff’s blog.

App note: Design considerations for mixed-signal, How to design a PCB layout

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Another application note from e2v, this time about PCB design involving mixed-signal (Analog and Digital) components. Link here (PDF)

This application note aims at providing you with some recommendations to achieve improved performance.

The initial assumptions are the following:
• Proper grounding and routing of all signals is essential to ensure accurate signal conversion
• Eliminate the loop area return by using both separate ground plane and power plane
• Circuitry placement on mixed-signal PCBs is a crucial design point

In many cases, engineers have preconceived notions about mixed-signal designs and how analog and digital placement, partitioning and associated design should be performed.

When laying out components for a mixed-signal PCB, certain considerations are critical to achieve optimum performance. Mixed-signal is particularly tricky to design since analog devices possess different characteristics compared to digital components: different power rating, current, voltage and heat dissipation requirements, to name a few.

This study shows how to prevent digital logic ground currents from contaminating analog circuitry on a mixed-signal PCB and particularly ADC component. In our attempt to answer this question, let’s keep in mind two basic principles of electromagnetic compatibility. One is that currents should be returned to their source as locally and compactly as possible, through the smallest possible loop area. The second is that a system should have only one reference plane, if not we would create a dipole antenna.