Archiwa kategorii: Elektronika / Electronics

SeeedStudio.com Fusion – New PCB Services from popular DIY and prototyping company

https://www.seeedstudio.com/fusion_pcb.html

I discovered SeeedStudio some time ago, since the company is pretty active in the internet (facebook, own wiki, some projects on github). Last month they introduced PCB manufacturing services, called „SeeedStudio Fusion Services”

I decided to give it a try, because the website looked pretty neat and modern. They also provided (see below) a little bit better specs than the others.

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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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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.

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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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Cheap PCB prototyping & manufacturing in China – reviews

Review of some Chinese PCB prototyping services and manufacturers

I’m in progress of testing some of cheap Chinese PCB manufacturers. I’m going to try to write detailed description for each of them.

Tested so far:

SeeedStudio Fusion

https://www.seeedstudio.com/fusion_pcb.html

SeeedStudio.com Fusion – New PCB Services from popular DIY and prototyping company

Dangerous Prototypes

http://dangerousprototypes.com/store

Dangerous Prototypes – PCB Manufacturer Review

DirtyPCBS

http://dirtypcbs.com/

DirtyPCBS.com – PCB Prototyping review

shenzhen2u

http://www.shenzhen2u.com/PCB

ShenZen2U PCB Prototyping Review

smart-prototyping

http://smart-prototyping.com/PCB-Prototyping.html

Smart Prototyping – PCB Prototyping review

ShenZen2U and SmartPrototyping looks bascily like the same company. But they are not (as SmartPrototyping explained).

AMD AM1 (Athlon 5350) Real power consumption

Rationale

A few days ago I was building rack 19″ server based on AMD Athlon 5350 CPU. The main goal was to create a hardware set that will operate on wide supply voltage ranges (48V, 24V, 19V) and will be power efficient.

I decided to take a look at quite cheap AMD AM1 Athlon APU with TDP said to be 25W.

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gcc / g++ – minimalizacja rozmiaru pliku binarnego, usuwanie nieużywanych funkcji

Wstęp

Rozmiar nas ogranicza. W przypadku komputerów klasy PC nie jest to problem aż tak znaczący jak w architekturze AVR, gdzie ogranicza nas pamięć o rozmiarze 4/8/16/32KB.

Sporo miejsca możemy zaoszczędzić zmuszając kompilator do optymalizacji rozmiaru, usuwając nieużywane funkcje z kodu, itp.

Mniejszy rozmiar pliku binarnego to także szybsze uruchomienie aplikacji.

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