Dangerous Prototypes – PCB Manufacturer Review

http://dangerousprototypes.com/store – another brand of DirtyPCBs, probably their „beta” site

My orders

For now, I have places three orders there, all with the same specification:

  • PCBs:
    • FR4
    • 2 layers
    • 10cm x 10cm
    • 10 pcs
    • 1.6mm thick
    • 1oz/ft2 = 35um
    • HASL
    • Green
  • Stencil: frameless

In one of my orders I also used free „panelization”. They allow to duplicate the same layout over one board – I had 4x 4.5cm x 4.5cm over one 10cm x 10cm piece.

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DirtyPCBS.com – PCB Prototyping review

http://dirtypcbs.com/store/pcbs – cheap Chinese PCB Manufacturer review

Update 05.12.16. The dirtypcbs site looks pretty new, it is now the same as http://dangerousprototypes.com/store

My order:

  • PCB
    • 2 layers
    • 10cm x 10 cm
    • 10 pieces
    • PCB Thickness: 1.6mm
    • Surface finish: HASA
    • Solder mask color: Green (all with the same price)
    • No sub-boards
    • 100% E-Test
  • Stencil – frameless 13cm x 21cm

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Jak stworzyć dyrektywę w AngularJS ? Na przykładzie prostej dyrektywy input-label-text.

Możliwe, że wielu z Was, przeglądając kod, natknęło się na magiczne wyrażenie ‚directive’. Czym tak naprawdę jest? Jak można coś takiego stworzyć samemu? Na te pytania spróbuję odpowiedzieć, opisując krok po kroku tworzenie prostej dyrektywy input-label-text.

  1. Czym jest dyrektywa w AngularJS?

    Jest to reużywalny komponent, w kodzie widoczny najczęściej jako znacznik (tag), atrybut lub wartość atrybutu. Klasycznie składa się z części skryptowej, gdzie możemy zdefiniować potrzebne zmienne, funkcje, etc. oraz z części HTML-owej, czyli tzw. template’a – kawałku kodu, ‚wstrzykiwanego’ w miejsce wywołania dyrektywy.

  2. Jak ją stworzyć? Jak skonfigurować swoje pliki, aby dyrektywa zadziałała?

    Pokaże to na przykładzie komponentu, który łączy ze sobą tagi <input> i <label> oraz implementuje prostą logikę w swoim własnym wydzielonym kontrolerze.

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JSoup mini-tutorial – parsowanie HTML w środowisku java

Wstęp

Biblioteka JSoup pozwala w sposób szybki i przyjemny przeparsować dokument HTML i wyciągnąć z niego interesujące nas dane. Używając gotowego parsera (zamiast na przykład wyrażeń regularnych) oszczędzimy sporo czasu i nerwów, a przede wszystkim umożliwimy samym sobie stworzenie czytelniejszego rozwiązania.

JSoup umożliwia zarówno klasyczne przechodzenie po drzewie (children <> parent), jak i wyszukiwanie węzłów po:

  • html’owym id
  • dowolnych atrybutach
  • html’owym class
  • html’owym tagu (czyli nazwie znacznika)
  • selektorze css (tak, jak w arkuszu styli / jQuery)

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AliExpress / EBay / China market fake DS18B20 Sensors

Update 23.05.2016

Some sensors MAY actually work. This does not discard what i wrote before (I tested them all), but: For some reason some of the sensors gives invalid response to ‚Power supply’ command. They always respond as they are parasite-powered. Some devices (ex. mine) do check that and reported them as invalid. However I tested all ‚Invalid’ with osciloscope. Some of them gave some response, so i took the deeper test.

Introduction

If you’re planning to order cheap DS18B20 sensors from AliExpress – keep in mind that irrationally low price (less than $0.8 / pc) smells really fishy.

Manufacturer price for 1k is $1.18.

My experience:

I recently ordered two six lots from two different sellers:

http://www.aliexpress.com/item/10pcs-lot-DS18B20-TO-92-18B20-chips-Temperature-Sensor/32615902919.html (Keeps data line low)

http://www.aliexpress.com/item/DS18B20-DALLAS-TO-92-Programmable-Resolution-1-Wire-Digital-Thermometer-new-and-original-free-shipping/32460503179.html (No response for presence)

http://www.aliexpress.com/item/10PCS-LOT-DS18B20-TO92-18B20-TO-92-Temperature-sensor-New-and-Origianl-DS18B20/32353012700.html (No response for presence)

http://www.aliexpress.com/item/Free-Shipping-10PCS-DS18B20-TO92-Sensor-18B20-TO-92-Digital-Thermometer/514174063.html (All works!)

http://www.aliexpress.com/item/Free-Shipping-10pcs-lot-DS18B20-18B20-TO-92-DALLAS-MAXIM-100-New-Original/883530054.html (Keeps data at +1.0V)

http://www.aliexpress.com/item/Free-Shipping-20pcs-DALLAS-DS18B20-18B20-18S20-TO-92-IC-CHIP-Thermometer-Temperature-Sensor/32236763433.html (All works)

In first case I received 4x DS18S20 and 6x something else (not really sure what, but definitely not DS18B20)

In rest none was DS18B20 sensor. Instead i got one NPN transistor, one PNP transistor and  8x something else (thyristors actually).

2016-04-26 16.25.03 2016-04-26 16.26.24

The easy test:

According to DS18B20 datasheet, there should be an input diode somewhere between VCC and GND. If you connect the sensor in the opposite way it should give a short.

To test it, I simply used multimetr with diode check mode, connected between VCC and GND.

For real sensor it should ‚detect’ the diode.

For fake of course it would not.

2016-04-26 16.09.19

Real DS18B20

2016-04-26 16.09.32

Fake DS18B20

 

 

How to recognize fake parts?

As for today (18.05.16) I see some common attributes of all fake parts:

  • They have DALLAS marking. Normally, when ordering from china, I got parts with ‚7Q-Tek’ or others. Some working parts have DALLAS also. But no DALLAS marking increases chances for working product.
  • Some fakes had +919AF serial code, none worked. The +233AA – some good, some dead
  • Surface with marking is ‚sandy’, not glossy. Its probably because of removed marking
  • The diode test (above)
  • Test for any communication

More information:

https://www.telldus.com/forum/viewtopic.php?f=12&t=5958

AliExpress Hidden search options: Show Price Per Piece, Max Quantity, etc

Some time ago AliExpress (and probably others of their family) has simplified their search engine, removing some useful search options like:

  • Sorting by price per piece / lot
  • Selecting maximum quantity
  • Showing price per piece

Although they are removed from the search panel, they are still valid and correctly parsed if added to URL.

To get those options, please append following parameters to URL. They are separated by & character:

Option Name URL Parameter
Show Price Per Piece isUnitPrice=y
Maximal quantity in lot maxQuantity=n
Minimal quantity in lot minQuantity=n

To get lowest price per piece simply combine: „Show Price Per Piece” + Order by Lowest Price + (optionaly) Maximal quantity

How to disable OnePlus / CyanogenOS application suggestions

If you are getting annoyed with recent update new feature showing microsoft office (and possibly other) applications as suggested while opening some files, here are steps to disable them:

  1. Go to Settings
  2. Go to Applications
  3. Swipe to All (last on the right) tab
  4. Find ‚Cyanogen Application Suggestions’
  5. Click
  6. Click Disable

Done

Smart Prototyping – PCB Prototyping review

http://smart-prototyping.com/PCB-Prototyping.html – another cheap Chinese PCB Manufacturer review

My order:

  • PCB
    • 2 layers
    • 10cm x 10 cm
    • 10 pieces
    • PCB Thickness: 1.6mm
    • Copper thickness: double – 2oz/ft2 = 70um
    • Surface finish: HASA
    • Solder mask color: Green (additional fees for other colors)
    • No sub-boards
    • 100% E-Test
  • Stencil – frameless 13cm x 21cm

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ShenZen2U PCB Prototyping Review

http://www.shenzhen2u.com/PCB – cheap Chinese PCB Manufacturer review

My order:

  • PCB
    • 2 layers
    • max 5cm x 5 cm
    • 10 pieces
    • PCB Thickness: 1.6mm
    • Copper thickness: standard – 1 oz/ft2 = 35um
    • Surface finish: HASA
    • Solder mask color: Green (additional fees for other colors)
    • No sub-boards
    • 100% E-Test
  • Stencil – frameless 19cm x 29cm

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