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Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, December 2nd, 2016 in Free PCBs by DP | No Comments

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:

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Bertan/Spellman 225-20R HV power supply teardown

Posted on Friday, December 2nd, 2016 in Teardowns by DP | No Comments

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Kerry Wong did a teardown of a Bertan 225-20R 20kV high voltage power supply:

I just picked up another high voltage power supply, this time it is a working Bertan/Spellman 225-20R 20kV one. Unlike the Bertan 205A-05R that I did a teardown with last time which was entirely analog, this one can be controlled digitally either via the front panel or via GPIB from the back. In this blog post, let me share some of the teardown pictures with you. If you are interesting in seeing some cool experiments with this high voltage power supply, you can scroll down and watch my video towards the end.

More details at Kerry D. Wong’s blog.

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

Adjusting clock with alarm, hygrometer & thermometer on 1.8″ ST7735 display

Posted on Friday, December 2nd, 2016 in Arduino, clock by DP | No Comments

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Nicu Florica blogged about his adjusting clock with alarm, hygrometer and thermometer on 1.8″ ST7735 display:

I use feature from article Another adjusting clock with alarm & thermometer using DS3231 on 1.8″ ST7735 display and change reading internal temperature of DS3231 with DHT22 senzor (AM2302), but you can use a cheaper and not very precise DHT11 senzor.
By using educ8stv_rtctft160_alarm_dht.ino or much better educ8stv_rtctft160_alarm_eeprom_dht.ino sketch, on display you can see: name of day, date, hour clock, hour alarm, temperature and humidity

Project details at Arduinotehniq blog.

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

How to run your ESP8266 for years on a battery

Posted on Thursday, December 1st, 2016 in how-to by DP | 2 Comments

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Here’s a detailed article on how to run an ESP8266 for a long time on a battery by Marco Schwartz:

For most of the projects I am building with the ESP8266 WiFi chip, I usually don’t care too much about the power consumption aspect. I for example build data loggers that are constantly connected to the mains electricity, and appliances controller which also have an easy access to power. However, in some cases, we want to build projects that are only powered by batteries. This is for example the case for a motion sensor that you will install in your home, or a data logger you would put in a remote location.

More info at Open Home Automation.

Qinsi-QS5100 Sn63Pb37 solder profile

Posted on Wednesday, November 30th, 2016 in tools by DP | No Comments

analysis

Alan Hawse from IOT Expert writes, “About 2 years ago, I bought a Qinsi QS5100 reflow oven from China via Amazon.com.  My decision was based almost completely on the nice youtube video that Ian Lesnet from Dangerous Prototypes posted about his results.  After I got the oven, I successfully built a series of Physics Lab boards with it.  Then one day about a year ago, I got two boards in a row with horrible results which I attributed to the temperature profile.  A few weeks later, I dug around on the internet and decided to change to the Lesnet profile and things seemed to be working again.”

More details at IOT Expert site.

Via the forum.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, November 29th, 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.

Big F’n 3D printer build

Posted on Tuesday, November 29th, 2016 in DIY by DP | No Comments

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Dan Beaven blogged about his big 3D printer build:

Summary of Features:

  • 8 Cubic foot print volume (capable of larger with minor changes – i.e bigger cast aluminum plate) – The reason I chose 1/4″ Cast Aluminum plate was to make sure it was dimensionally stable when heated.  Anything else will most likely warp over that big of an area.
  • X, Y, Z end stops
  • Filament runout sensors to pause BIG jobs
  • Auto leveling bed (4 steppers to support heavy weight, but also allow auto leveling in addition to Z-probe) – used CNC shield board with 4 stepper drivers tied to the Z lines on the RAMPS 1.4 board.
  • Smoke senbigsor (separate from main control system – tied to power supply inhibit lines) – no one wants to burn their house down.
  • FLIR Lepton module to monitor and provide feedback on heat distribution for design improvements.
  • Dual Bowden extruders (allow fast transits by minimizing weight of extruder sled)
  • Heated bed (cast aluminum plate and four 280 watt silicone heating pads)
  • Had been named “Big Fucker” because I managed to hit my head many times working on it and assembling it.
  • Inductive Z probe

Full details at Dan’s blog.

Temperature alarm for boiling milk

Posted on Tuesday, November 29th, 2016 in project logs by DP | No Comments

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Domen Ipavec shares his temperature alarm for boiling milk in the project log forum:

Anyone who has ever boiled milk on the stove knows, that it has a nasty habit of overflowing. That is why I created the temperature alarm for boiling milk to be used my mother.
The temperature alarm uses attiny841 microcontroller and DS18B20 to continuously measure the temperature of the milk and sounds an alarm when the temperature is over the preset alarm value.
I’ve designed the pcb in KiCAD, etched the pcb at home and soldered it together.
The case is made from 4mm plywood and the buttons are small pieces of wooden rod glued to a square piece of plywood so they can not fall out.

Project info at Domen Ipavec’s blog.

Free PCB Sunday: Pick your PCB

Posted on Sunday, November 27th, 2016 in Free PCBs by DP | 33 Comments

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:

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App note: TPS25810 Charging Port Over USB Type-C™

Posted on Sunday, November 27th, 2016 in app notes by DP | No Comments

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Allow more current from USB Type-C port, an application note from Texas Instruments utilizing TPS25810 and TPS2544 USB port manager. Link here (PDF)

The TPS25810 is a USB Type-C downstream facing port (DFP) controller that monitors the USB TypeC™ configuration channel (CC) lines to determine when a USB device is attached. When the upstream facing port (UFP) device Type C-to-B dongle is plugged in, the port supports connection of Type-B receptacle devices such as a mouse, smartphones, keyboards, external hard drives, and so forth. As these devices monitor the USB 2 data line (D+/D–), the TPS2544 USB charging port controller can be added to provide the electrical signatures on D+/D– to support BC1.2 and non-BC1.2 compliant charging schemes. This application note presents the design solution which offers fast charging of popular mobile phones, tablets, and media devices over the USB Type-C port.

App note: bq77905 20S cell stacking configuration

Posted on Sunday, November 27th, 2016 in app notes by DP | No Comments

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Application note from Texas Instruments on their bq77905 ultralow power stackable battery protector. Link here (PDF)

The bq77905 is a 3-5S Low Power Protector with easy stacking capabilities for higher than 5S cell battery packs. This document provides an example for setting up a stacking configuration with the bq77905 and exhibits detailed analysis of the stacking functionality.

App note: Universal motor drive with PIC16 microcontrollers

Posted on Sunday, November 27th, 2016 in app notes by DP | No Comments

appnote

An open-loop speed control TRIAC-driven universal motor driver board design from Microchip, app note here:

This application note presents the design of an open-loop speed control TRIAC-driven universal motor driver board using a variety of core independent peripherals on an 8-bit microcontroller. The complete source code and reference design material are included.

 

Updating the KLN89B

Posted on Saturday, November 26th, 2016 in hacks by DP | No Comments

kln89b_dbid

Dmitry Grinberg writes, “Updating a 1996 plane GPS the 2016 way.  Reverse engineering of old proprietary data cards, formats, binaries, creating of new tools to perform updates and their final open-source release.”

More details at Dmitry Grinberg’s blog.

Via the contact form.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, November 25th, 2016 in Free PCBs by DP | No Comments

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:

(more…)

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, November 22nd, 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.

Free PCB Sunday: Pick your PCB

Posted on Sunday, November 20th, 2016 in Free PCBs by DP | 29 Comments

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:

(more…)

App note: Sensorless speed stabilizer for a DC motor

Posted on Sunday, November 20th, 2016 in app notes by DP | No Comments

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Precision Microdrives’ sensorless speed sense by exploiting speed dependent back EMF voltage. Link here

Motor speed is a parameter of a DC motor that is often measured and controlled, usually through additional sensors and with closed loop feedback. This method of speed control requires some form of speed sensor, normally mounted on the motor shaft. Some of our DC motors and gearmotors have rear shafts for just this purpose

Hall sensors and opto sensors are commonly used with digital controllers, whilst analogue circuits often use tacho-generators. With PWM control it is possible to achieve good accuracy, flexibility, and reduce power losses. However this comes at the cost of an additional component and potentially a mechanical design modification if you’re planning to use it in an existing product.

For brushed DC motors it’s possible to measure and control speed without any sensors on the motor, exploiting a basic characteristic – speed dependant back EMF voltage.

App note: Lifetime of DC vibration motors (MTTF & FIT)

Posted on Sunday, November 20th, 2016 in app notes by DP | No Comments

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DC vibration motors failure analysis by Precision Microdrives. Link here

Reliability is an important consideration for engineers and product designers. It is also very context specific. For example consider a car, which is made from lots of individual components. If the radio antenna should fail, the car still operates. However this is not the case if the engine stops working. Some features are more important than others, especially with safety systems such as the car’s brakes.

In relation to vibration motors and their typical applications we can consider them as individual components or entire systems. Haptic feedback on a user interface is comprised of the input system (such as a touchscreen), the microcontroller, the motor drive circuit, and the vibration motor. If any one of these should fail, then the vibration feature will no longer work.

As with any component, our vibration motors will eventually stop working. The key therefore is accurately estimating when, and determining if it is an acceptable period of time. To do this, we can use one of a number of different methods for calculating the probability of a component’s life expectancy.

36dB power attenuator for 20W

Posted on Saturday, November 19th, 2016 in DIY by DP | 1 Comment

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Lex PH2LB designed and built a 36dB power attenuator for 20W using PA1B power attenuator calculator:

The attenuator can handle a maximum power of 20 watt and is used to reduce the power of a 5 watt transceiver.
At first I did not realized why Lex designed the attenuator for 20 W. Like many HAMs I thought, that 20 W is QRO. But please notice that 20 W is the Maximum power. The chosen maximum power of 20 watts for the attenuator is an excellent choice. The attenuator can easily handle a power of 5 watts, without getting hot.

More details at Lex PH2LB project page.

Via PA1B’s QRPp blog.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, November 18th, 2016 in Free PCBs by DP | No Comments

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:

(more…)

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Recent Comments

  • David Haile: You are a smart person and absolutely correct. That kind of current needs a lead acid car battery behind it. Still, it does have its...
  • KH: The solution discussed in the linked article is wrong. It's a largish Lipo (2500mAh) and he thinks 77uA is acceptable... ha ha ha ha ha....
  • Dave: I never had to opportunity to learn or use this stuff when I was in college (I'm sooo old that op-amps were just being developed...
  • Matthias: Aww yeah.
  • Samuel: Have a nice week everyone