Weather logger with Losant and Amazon Alexa

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Steve documented his experience experimenting with home weather logging:

Like a million other people on the Internet, I’ve been experimenting with home weather logging. I roll my eyes at the phrase “Internet of Things”, but it’s hard to deny the potential of cheap networked sensors and switches, and a weather logging system is like this field’s Hello World application. Back in June I posted about my initial experiments in ESP8266 weather logging. Since then I’ve finalized the hardware setup, installed multiple nodes around the house, organized a nice web page to analyze all the data, and integrated everything with Amazon Alexa. Time for an update.

More details at Big Mess o’ Wires homepage.

Check out the video after the break.

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Transistor radio series – The 7 MHz scratch synthesizer

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Vasily Ivanenko has written up documentation on his 7 MHz synthesizer project:

Above — All 4 boards were built in re-purposed Hammond boxes. A PIC-based counter sits on top of the offset mixer. I build modular gear and this allows modification and fosters experimentation. When I build a final transistor radio receiver, I plan to place the offset mixer, PLL circuitry and VXO on the same board inside the radio with some shielding. My VCOs always go in a RF tight container. A 0.0033 µF feed through capacitor connects the VCO varactors to the outside world.

See the full post on his blog, QRP HomeBuilder.

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#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.

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Teardown of an ATVR-1000D AC voltage regulator

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Kerry Wong did a teardown of an ATVR-1000D automatic AC voltage regulator and discussed how different types of AC regulators work:

The ATVR-1000D utilizes a motor to drive the wiper of a autotransformer (Variac), the servo motor can be driven in either direction depending on the output from the OpAmp (LM324) based comparator. Comparing to a voltage regulator that uses relays for tap-switching, this type of servo-driven voltage regulator has several advantages. It offers continuous voltage adjustments as opposed to the limited discrete steps offered by relay-switching regulators. Also the output waveform is continuous.

See the full post on his blog.

Check out the video after the break.

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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:

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: Thermal design calculations for integrated stepper motor driver solutions

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Another technical note from STMicroelectronics on fine tuning motor drivers for optimal thermal design. Link here (PDF)

One constant trend in the automotive world is the tendency to reduce the size of electronic components and the ECUs (Electronic Control Unit). While this development has many benefits for the car manufacturer as well as for the end customer, there are also challenges for the developers of these systems: especially for power drivers the design of robust applications requires an accurate estimation of the thermal power dissipation on a system level.

In this article a method to calculate the thermal power dissipation of a stepper motor driver is derived from a simple example to a model that includes the various configuration options and modes of a state of the art stepper driver, like that of ST Microelectronic’s L9942.

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App note: Pop & click in audio amplifiers

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Technical note from STMicroelectronics about popping noise usually heard on audio amplifiers and how to minimize it. Link here (PDF)

Pop and click, or rather, the absence of it, is a characteristic that makes a lot of impact in the world of audio amplifiers. This is especially true for those destined for headphone-equipped applications (such as mobile phones and MP3 players).
Pop and click are the names given to the popping noise that may be heard through the headphones when you switch on or off portable audio equipment or mobile phones. The noise is generated by a voltage difference at across the output stage of the amplifier at switch-on or switch-off before it reaches its idle (or equilibrium) state.

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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:

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.

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