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.

from Dangerous Prototypes https://ift.tt/2PURr8Y

Big Timer

BigTimers

Dr. Scott M. Baker 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.

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

24bytesleft

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.

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#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.

from Dangerous Prototypes https://ift.tt/2PMz2Lp

Tutorial, experiment and teardown of a 24GHz Doppler radar module

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Shahriar posted a detailed analysis of a CDM324 24GHz Doppler radar module from IC Station:

Opening the module reveals a series of microwave PCB components and several active devices. A complete analysis of the module is presented. The unit is then measured and the impact of antenna impedance and power supply voltage on the output frequency is measured. The phase noise of the output signal is also measured. Using a series of servo motors, the radiation pattern of the antenna array in both azimuth and elevation is also presented.

More details on The Signal Path 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.

from Dangerous Prototypes https://ift.tt/2P9mdJY

App note: Designing applications with Lithium-Ion batteries

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More Li-ion battery applications from Richtek. Link here (PDF)

Lithium-Ion batteries have several advantages when compared with other battery types: They are light weight, and energy density of lithium-ion is typically twice that of the standard nickel-cadmium. Li-Ion batteries have no memory effect, and the self-discharge is 6 ~ 8 times less compared to nickel-cadmium. The high cell voltage of 3.6 volts is often sufficient to power applications from a single cell. These properties make Li-Ion batteries very popular in modern portable electronic applications.

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App note: Switching battery chargers

an_ricktek_an050

App note from Richtek about several aspects of switching chargers for single cell Li-Ion batteries. Link here (PDF)

Longer battery life and shorter charging times are some of the challenges in battery management in modern hand-held applications like Smart-Phones, Tablet PCs, POS and other portable equipment.

Devices with powerful processors are more power hungry and require larger capacity batteries to guarantee battery life. To quickly charge large capacity batteries, powerful high current chargers are needed. Linear chargers have too limited charge current capability for this purpose, so switching charger topology has to be adopted.

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Grbl_ESP32 CNC development board

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Bart Dring has designed a development board for using CNC on Grbl ESP32:

This is a Grbl_ESP32 CNC Development board. This is a quick and easy way to use and test CNC on the ESP32 controller.
Grbl is a great CNC firmware that has been around for nearly a decade. It was originally designed for the Arduino UNO and basic 3 axis CNC routers, but it has been ported to other CPUs and was the basis for many other CNC and 3D printer firmwares.

Project info at Buildlog.Net Blog. It’s also up on Tindie.

from Dangerous Prototypes https://ift.tt/2NgX0gf

#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.

from Dangerous Prototypes https://ift.tt/2MEp8wC