#FreePCB via Twitter to 2 random RTs

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.

SAMD21 LoRa development board with GPS

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Michael Krumpus designed and built a SAMD21 development board with LoRa radio module and GPS receiver, that is available on GitHub:

I’ve been doing some LoRa projects lately in order to learn as much as I can about this exciting new radio technology (see this LoRa mesh networking project and this LoRa weather station). ATmega328-based Moteino modules work great for a lot of projects, but I wanted a LoRa node with more processing power, more memory, and an onboard GPS receiver. The ATmega328 is just too constrained with memory — I’ve outgrown it. I really wanted a LoRa board with an ARM Cortex microcontroller like the SAMD21. This is the microcontroller used on the Arduino Zero. So, my ideal board is a SAMD21 with LoRa radio module and GPS receiver, all programmable with the Arduino IDE.
But, where is such a board? I could not find one so I decided to design and make one myself.

More details on Project Lab.

Free PCB Sunday: Pick your PCB

BP-600x373

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: Common mode filter inductor analysis

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App note from Coilcraft on the design and construction of common mode filter inductor. Link here (PDF)

Noise limits set by regulatory agencies make solutions to common mode EMI a necessary consideration in the manufacture and use of electronic equipment. Common mode filters are generally relied upon to suppress line conducted common mode interference. When properly designed, these filters successfully and reliably reduce common mode noise. However, successful design of common mode filters requires foresight into the nonideal character of filter components — the inductor in particular. It is the aim of this paper to provide filter designers the knowledge required to identify those characteristics critical to desired filter performance.

App note: How current and power relates to losses and temperature rise on inductors and transformers

Coilcraft’s app note on temperature rise due to losses on inductors and transformers. Link here (PDF)

Core and winding losses in inductors and transformers cause a temperature rise whenever current flows through a winding. These losses are limited either by the allowed total loss for the application (power budget) or the maximum allowable temperature rise.

For example, many Coilcraft products are designed for an 85°C ambient environment and a 40°C temperature rise implying a maximum part temperature of +125°C. In general, the maximum allowed part temperature is the maximum ambient temperature plus temperature rise. If the losses that result in the maximum allowed part temperature meet the power budget limits, the component is considered acceptable for the application.

Free PCB coupon via Facebook to 2 random commenters

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:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

N6QW Heathkit SSB transceiver

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Pete Juliano, N6QW,  has a nice build log on his newest version Heathkit 40M SSB Transceiver:

What are you thinking — I am not trying to break any world record? My XYL asked me that question today — why are you building another rig? Followed up by a snide comment that I had so many rigs now why do I need another one. Well the answer plain and simple because I can!
For the longest time in the late 60’s early 70’s my success rate with homebrew SSB transceivers was miserable. At that time I lacked the more sophisticated test gear and let’s face it some of the technology wasn’t that great. Crappy Analog VFO’s were high on the list of impediments! I also had to work and to give a fair share of my time to the family — it is that balance thing.
But today that is all changed –better test gear, better technology like Digital VFO’s and a bit more time. The latest project is to demonstrate that some of the components out of boat anchors can indeed be reworked to provide a very modern, very capable rig.

See the full post on N6QW blog.

Check out the video after the break. Continue reading “N6QW Heathkit SSB transceiver”

#FreePCB via Twitter to 2 random RTs

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.

Battery monitor on a automotive relay form factor

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Jesus Echavarria made this battery monitor and wrote a post on his blog detailing its assembly:

Here’s one of the design I do last year for a client. He wants to measure the voltage of a car battery and set a couple of alarms when voltage falls below a defined values. Also, he wants to put the device in the relay box of the car, so the design needs to have a relay form factor to easy integration. So, after a couple of iterations, here’s the final design of the battery monitor.

Via Designing Electronics in Spain.

ICSP switch box

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Stynus has published a new build:

For a project I need to program a few microcontrollers in the same circuit. This meant I needed to plug the programmer around on the board a lot.  This got annoying very fast. Therefore I decided to make a switch box. In my junk pile I found an old switch of a, parallel port switch. This has 4 positions and a lot of contacts. For the ICSP I only need 3. However in some circuits the supply voltage is not common. Hence, I chose to also switch the power supply connections.  For the connections to the circuit boards I used DIN connectors, for the simple reason I have lots of these.

See the full post on ElektronicaStynus blog.

Free PCB Sunday: Pick your PCB

BP-600x373

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: How to use LEDs with supervisory ICs for undervoltage and overvoltage fault indicators

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Another app note from MAXIM Integrated utilizing supervisory chip and LEDs to indicate voltage faults. Link here

Traditionally, supervisory ICs have been used to monitor voltage rails for undervoltage faults (UV). When a supply rail falls below a set threshold, the system is held in reset using the reset output signal to the microcontroller to prevent erratic behavior or catastrophic failure.

App note: How a SIMO PMIC enhances power efficiency for wearable IoT designs

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App note from MAXIM Integrated on very compact PMIC using only single inductor to drive three independent switching regulators. Link here

Small form factor and minimal power loss are key criteria for internet of things (IoT) hardware, particularly wearables. Meeting these criteria typically involves some tradeoffs. For example, to meet a specific power consumption goal, a designer usually would have to compromise with an increase in design size.

Free PCB coupon via Facebook to 2 random commenters

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:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

DIY custom power supply

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Anthony Lieuallen made this custom power supply and wrote a post on his blog detailing its assembly:

You might not truly be an electronics nerd until you build your own power supply. Either way, I’ve finally passed that threshold. As I’ve mentioned previously (and previouslier), I’ve been working on mine — very slowly, off and on — for most of a year. The bare start came with a guide posted to Hackaday about using nichrome wire to heat and bend acrylic plastic in straight lines, to make cases.

More details at Arantius.com.

Povon home energy monitor part 1, 20 channel system

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Coyt Barringer documented his home energy monitor project called POVON. This first part of a series will detail the 20 Channel sub-metering hardware:

Our initial goal was to monitor power consumption in different parts of the house, and we quickly realized every household circuit would need to be monitored. After some research, small clip on current transformers, or CT’s, looked to be the best sensor for our application. Using CT’s, current draw and thus power on each circuit can be measured. The CT’s would be installed on the wires immediately leaving the circuit breakers in the standard household breaker box. CT’s work great for this because they’re completely isolated and nothing needs to be disconnected to install them.

Project info at lostengineer.com.

uMesh – A self-contained, battery operated ESP32 module

Jarrett published a new build:

I’ve been working on an ESP32 module. Part of the problem I’ve been seeing with inexpensive IoT dev boards, is that the design around the power system hasn’t been very good. Here’s my attempt to fix that. This is a battery-ready module with a proper lithium battery charge circuit, lithium battery protection circuit, power supply, and antenna, all in a 1 inch by 1 inch package.
The goal is to have a tiny, inexpensive module that can immediately accept a battery and be deployed in the field, along with 30 of its mates.

See the full post on his blog.

#FreePCB via Twitter to 2 random RTs

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.

Vintage headset conversion

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Quinn Dunki wrote a great article describing the conversion process of a 1980s-era Earmark into a bluetooth headset:

The obvious thing is to convert it to a bluetooth headset for modern use, right? As I previously warned, converting a 1980s-era air traffic control headset into bluetooth headphones is probably the most hipster thing possible. Normally, I don’t allow projects like this around here. But look at these headphones. They are amazing and I love them and I want to use them so I am going to make them bluetooth also shut up. If I have to punch myself as result of now being a hipster tool, so be it. I set out to do this in a non-destructive way that was reversible, at the very least. I wanted to respect the original hardware as much as possible.

Via Blondihacks.