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Dewalt DW9118 battery charger teardown

Posted on Wednesday, July 13th, 2016 in Teardowns by DP | No Comments

Dewalt DW9118 battery charger teardown video from Electronupdate:

Tear down of a failed Dewalt DW9118 charger. A look at the circuit board, the fuse, circuit topology and a decap an analysis of the Zilog Z86C04 controller.

More info at Electronupdate blog.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, July 12th, 2016 in Free PCBs by DP | No Comments

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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.

Factory programming ESP8266 gadgets

Posted on Tuesday, July 12th, 2016 in DIY by DP | No Comments

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Johan Kanflo’s Esprog pogo pin connector:

The FTDI connector can be found on just about any ESP8266 design. If you are building a gadget to be deployed somewhere and not a full blown development board, the FTDI connector is somewhat overkill. And it is quite large. A few pins could be shaved off but we still have a through hole connector invading the other side of the PCB.  I ended up designing my own connector and it has been used sucessfully in all of my recent projects. The connector consists of five test points providing power, GND, TXO, RXI and GPIO0 for boot control. It takes very little single sided PCB space and is inspired by the TagConnect I use at work. Note that the power provided through the connector is unregulated.
I also designed a pogo pin connector to mate the test points and a small board with a DC barrel connector and the FTDI connector. This board has two switches for power and boot mode selection.

More info at Johan Kanflo’s blog.

App note: Rectifiers for Power Factor Correction

Posted on Sunday, July 10th, 2016 in app notes by DP | No Comments

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Another Vishay’s app note about power factor correction this time about the component used and their effects. Link here (PDF)

PFC devices are generally selected base on the speed of their reverse recovery time (trr). Currently for CCM (Continuous-Conduction-Mode) and CRM (Critical Conduction-Mode) PFC devices in market, rectifiers up to 600 V with trr smaller or equal to 35 ns are generally used as CCM PFC; rectifiers up to 600 V with reverse recovery time between 35 ns to 60 ns are used as CRM PFC.

It should be noted there is a tradeoff between forward voltage drops and switching speed; when the reverse recovery time of Ultrafast rectifiers are less than 35 ns, their forward voltage drops would increase significantly, in turn the devices’ forward surge current abilities would be diminished, therefore cautious attention should be taken when selecting the appropriate CCM or CRM PFC devices for various switch mode power supply applications, such that expected performance could be achieved and better reliability would still be ensured.

Free PCB Sunday: Pick your PCB

Posted on Sunday, July 10th, 2016 in Free PCBs by DP | 29 Comments

IRToy 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:

(more…)

App note: Power factor correction with ultrafast diodes

Posted on Sunday, July 10th, 2016 in app notes by DP | No Comments

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Vishay’s app note in keeping the power supplies’ power factor in check with their ultrafast diodes. Link here (PDF)

More and more switched mode power supplies (SMPS) are being designed with an active power factor correction (PFC) input stage. This is mainly due to the introduction of regulations aimed at restricting the harmonic content of the load current drawn from power lines. However, both the user and the power company benefit from PFC, so it just makes good sense.

App note: Stepper motor control using the PIC16F684

Posted on Saturday, July 9th, 2016 in app notes by DP | 1 Comment

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Stepper motor control using the PIC16F684 application note (PDF!) from Microchip:

This application note describes how to drive a bipolar stepping motor with the PIC16F684. The Enhanced Capture Compare PWM (ECCP) module is used to implement a microstepping technique known as hightorque microstepping. The microcontroller’s 8 MHz internal oscillator allows the signals generated by the ECCP module to achieve frequencies above the audible range.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, July 8th, 2016 in Free PCBs by DP | No Comments

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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:

(more…)

ESP8266 based plane spotter

Posted on Friday, July 8th, 2016 in how-to by DP | 1 Comment

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A how-to on building an ESP8266 based plane spotter from Daniel Eichorn:

In order to get this project running you’ll need the following list of hardware:

  • NodeMCU ESP8266 module or Wemos D1 Mini
  • 0.96″ SSD1306 OLED display
  • A few connectors and USB Wire
  • Or order a complete starter kit from my shop

Full details at Squix TechBlog.

Die photos of the ICs on a EEVBLOG uCurrent

Posted on Friday, July 8th, 2016 in components by DP | No Comments

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electronupdate writes, “Managed to destroy one of my EEVblog ucurrent adaptors. Took the opportunity to remove the IC’s and de-cap them to study the dies.”

More details at electronupdate blog.

Check out the video after the break. (more…)

DIY self sustaining solar powered backyard hydroponic garden

Posted on Friday, July 8th, 2016 in Arduino, DIY by DP | 2 Comments

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Dan Beaven has been working on his DIY backyard solar powered hydroponic garden.

More details at Dan Beaven’s blog.

Via the contact form.

ESP8266 NodeMCU Backdoor uPWM hack for IR signals

Posted on Wednesday, July 6th, 2016 in how-to, infrared by DP | 2 Comments

ESP8266-NodeMCU-uPWM-Inverted-IR-Circuit

The AnalysIR crew has published an article showing how to achieve accurate PWM for Infrared carrier signals on the ESP8266 NodeMCU:

Quite simple really – just set the baud rate to 10 times the desired Infrared carrier frequency and send a ‘magic’ 8 bit character to achieve the desired duty cycle. Of course we need to take the 1-start bit and 1-stop bit into account plus the 8 bits in each character. Remember that the UART sends the data inverted, so this needs to be taken into account with the characters sent and also in the IR LED driver circuit above, which required 2 transistors instead of the usual one.

More details at AnalysIR blog.

215 Hopper FPV rebuild

Posted on Wednesday, July 6th, 2016 in DirtyPCBs.com by DP | No Comments

215HopperFPV

Andrew Taylor documented his 215 Hopper FPV build:

I finally have the design of the 215 Hopper at a point where I think it is fit for purpose as an FPV copter. It can now sustain a heavy grounding without terminal damage. I still won’t claim that it is as durable as a carbon plate design but I am now happy to release it. The camera pod is perhaps the least durable part of the design however I am still flying with the first one I printed and it has served its purpose protecting the flight cam. I do intend to upgrade it at some point but that will probably come after the custom camera pod for my Shendrones Tweaker.

All project files are available at Thingiverse.

More info at Andrew Taylor’s blog.

Understanding Arduino UNO hardware design

Posted on Wednesday, July 6th, 2016 in Arduino by DP | No Comments

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Yahya Tawil over at All About Circuits has published an article on Arduino UNO’s electronic design and better understanding of its hardware:

This article explains how Arduino works from an electronic design perspective.
Most articles explain the software of Arduinos. However, understanding hardware design helps you to make the next step in the Arduino journey. A good grasp of the electronic design of your Arduino hardware will help you learn how to embed an Arduino in the design of a final product, including what to keep and what to omit from your original design.

Full details at All About Circuits homepage.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, July 5th, 2016 in Free PCBs by DP | No Comments

BP-600x373

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.

Fun with Analog multipliers: Squares, cubes, and VCAs

Posted on Tuesday, July 5th, 2016 in how-to by DP | No Comments

Craig writes, “Need a frequency doubler? Want to plot a cubic function on your ‘scope? How about a square root extractor, or a voltage controlled amplifier? Analog multipliers make all this (and more) a snap!”

Details at Analog Zoo homepage.

Georges F6DFZ’s very stylish homebrew version of the Scout Regen receiver

Posted on Tuesday, July 5th, 2016 in DIY, RF by DP | No Comments

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Dave Richards AA7EE has published an article about Georges F6DFZ’s homebrew regen receiver:

Several months ago, Georges F6DFZ sent me pictures of a Manhattan project he had just completed, using Rex’s MeSQUARES, and I have waited far too long to share it with you. It began life as a copy of the Ten Tec 1253 regen, but George said that the results and usability were very poor. One thing that must be said about regens is that the ones which don’t work well are very dispiriting. However, when you come across a good design and build it well, the performance can be very satisfying indeed. Luckily, Georges didn’t let his initial regen experience put him off, and he ended up turning the project into a receiver based on the Kitchin-inspired Scout Regen. He normally uses PCB software to design custom boards for his projects, but decided to try Manhattan construction for this receiver.
I like how his project was obviously the result of considerable careful planning

More details at Dave Richards AA7EE blog.

HydroBot

Posted on Monday, July 4th, 2016 in DIY by DP | 3 Comments

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Matthew Reed writes:

HydroBot is a modular control system for automating hydroponic gardens. This system is designed with three objectives in mind. First, it will facilitate optimal growing techniques by using scheduling and feedback control loops to maintain state and adapt to changing conditions. Second, it will simplify controls interfaces, making setup and use easier for less tech-savvy gardeners. Finally, the components will be designed in a modular way to increase flexibility and support every imaginable garden configuration. HydroBot aims to bring sensors and actuators together through automation, which will allow hobby growers to focus on growing and not on constantly monitoring and adjusting the environment to keep their garden stable.

More details at Protofusion.org.

App note: Limiting inrush current

Posted on Sunday, July 3rd, 2016 in app notes by DP | 4 Comments

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Aimtec’s app note on inrush current on power converters and their solution. Link here

Inrush currents can be problematic in circuits that utilize overload protection devices such as fuses and circuit breakers. The selection of overcurrent protection devices is made more complicated when high inrush currents are present. False overload conditions can trigger unwanted protection events.

Free PCB Sunday: Pick your PCB

Posted on Sunday, July 3rd, 2016 in Free PCBs by DP | 33 Comments

IRToy 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:

(more…)

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Recent Comments

  • Alan: Reminds me of "bug zappers" shaped like tennis racquet. Outer mesh is ground for human contact, inner mesh has high voltage. They typically run from...
  • KH: He had qualms about electrolytic cap leakage impacting sleep current. I think such leakage is very low and hard to measure using hobby equipment, so...
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