Author Archives: DP

App note: Watt-hour meter based on the STM32F101 microcontroller

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ARM Microcontroller based watt-hour meter implementation from STMicroelectronics. Link here (PDF)

This document describes, in detail, the hardware and software implementation of a watthour meter using the STM32F101 microcontroller. This cost effective watt-hour meter uses shunt with an operational amplifier as a current sensor, an embedded 12-bit ADC for current and voltage measurement, GPIO for LCD management, and a lot of other peripherals for communication, tamper detection, keyboard, and power disconnection. Powerful architecture of the STM32™ microcontroller allows sampling at 1 Msps. The high sampling rate makes it possible to use methods for ADC resolution enhancement.

Free PCB coupon via Facebook to 2 random commenters

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BP

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.

Weather logger with Losant and Amazon Alexa

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losant

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.

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.

#FreePCB via Twitter to 2 random RTs

via Dangerous Prototypes

BP

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.