by Rusivan @ instructables.com:
In this article I will try to tell you about the gift I made for my girlfriend!
The basis of the scheme is a microcontroller Atmega8, 1K resistor, selected in such a way as not to overload the microcontroller ports. SMD resistors and diodes, size 1206.
On the reverse side of the board, there are two batteries CR2032, two capacitors, voltage regulator LM7805, and the power button with latching.
DIY SMD LED heart - [Link]
Vassilis over vpapanik.blogspot.gr has build a nice and simple tool to help him soldering tiny SMD parts on a PCB. The tool consists of three metal parts you can easily find on your parts box and it can be proven to be really helpful as it keeps the SMD parts steady while you solder them. The build is easy, all you have to do is to bend the main rod, file the tip to conical shape and drill the other two rods. All steps can be done in under 30 minutes without special tools. Sure it can be your third hand while assembling your PCBs. He writes:
I ordered this awesome N|Watch kit the other day, which requires some serious SMD hand-soldering skills. There’s always the easy alternative to use a reflow oven, but guess what, there is no stencil included (and no, I don’t have a paste dispenser). In a desperate need of a third hand (!) in order do a neat job, I saw some similar DIY solutions (thumbs up for Google images) and managed to build my own version in less than 30 minutes, just using junk metal parts : the SMD beak !
The SMD beak - [Link]
by Alan @ kalshagar.wikispaces.com:
I found those beautiful vintage IV9 & IV16 tubes and I had to use them, clock being the perfect candidate. I made already mutliple others based on what was supposed to be a WordClock (hence the project name) only, but became more diversified. I did also a first test with a chainable 5cm x 5cm tube board, this is a 5cm x 10cm dual board improved version.
When I made this project and designed it the idea I had was of course the design (very important) but also reusability and pragmaticallity regarding the components used. What I mean by the latest is that you never really know what component you’ll have at hand, depends on your provider, the component availability, it’s price, or even the package DIP or SMD. Hence the board can work with 3 different type of RTC clocks: just use your favorite or the one in your shelf stock. Personally I love the Maxims DS3231 and DS3234 which are temperature compensated (to a fantastic extend for the DS3234), and both are accessed through different protocols: SPI for the DS3234 and TWI for DS3231. There’s also the EPSON RTC4543 for those living in Japan like me. So again depending of what else you need to wire, choose your poison: all the pins of the MCU are accessible and there’s even a small zone for some DIP components.
The top board uses 74HC595 for maintaining the displayed digits: they come very cheap but I didn’t want to be stuck to the DIP or SMD model (having both in stock), so the board can use any of the two. Same goes with the current limiter resistors: SMD, through hole or even resistor array, your pick. And of course there’s a SMD or DIP led footprint under each tube for the blingbling! (single color, not RGB led)
IV9 & IV16 tube numitron clock - [Link]
by Mike Senese @ makezine.com:
Typically when electrical engineers wants to make a new circuitboard, they need to send their design files to a manufacturer and wait for it to be produced and mailed back. Hardware startup Voltera aims to expedite this process by putting it in on your desk with its V-One consumer circuit board printer.
Print Your Own Circuit Boards and Reflow SMD Components with the Voltera V-One - [Link]
This is reflow soldering controller for use with a toaster oven as reflow soldering oven.
I bought the toaster oven in a local super market for about 40 €. There was also a cheaper oven on sale, but I wasn’t sure if it did 250°C, so I bought the more expensive and prettier one.
Since I don’t want to loose the warranty and also haven’t any interest of the oven’s internals, I designed the reflow controller as an oven-external device which directly switches the oven’s mains on/off.
The relay I use is for 6V, but it seems to work just fine with the 5V supply from the ATtiny. On the mains side, the relay is rated for 230V/16A.
The whole controller is based on a ATtiny 45 µController. I use one pin as input for the 100k thermistor for temperature measurement (connected to JP3), one pin controls the mains relay (via a BC140 transistor), one pin controls a LED for feedback and one pin is connected to a switch for user input.
Reflow Soldering Controller - [Link]
For a project of mine, I need to flash several hundred of ATMegas.
I use a special programming connector, which sits on the SMD chip and connects directly to the ISP and power pins on the chip.
My first attempt to ease the flashing process was to mount the programming connector to a lever with some additional weight on it. That way, once the connector was in place, I didn’t need to hold down the connector manually during the flashing process.
The PCBs come in panels of 40 (10 x 4 PCBs per panel) with milled slots in between each PCB. So to make the positioning of the PCBs under the connector a little easier (and more repeatable), I put two metal pins (with the same diameter as the milled slots) on the base of the lever.
Flash several hundred of ATMegas using a CNC - [Link]
by EEVblog @ youtube.com:
Dave shows you how to reverse engineer a PCB to get the schematic. In this case the new Rigol DS1054Z oscilloscope.
How does the discrete transistor analog front end and the software bandwidth limiting work?
How do you decode SMD transistor codes?
How does it compare to the old Rigol DS1052E?
Dave also discusses the low voltage ohms function of a mulitmeter, how it’s useful, and how to test your multimeter to see if it will have any issues with in-circuit testing.
EEVblog #675 – How To Reverse Engineer A Rigol DS1054Z - [Link]
Geir Andersen over at LetsMakeRobots has designed and built this cool solder paste dispenser:
As I’m doing SMD prototypes I wanted to do reflow soldering instead of hand soldering and needed a solder paste dispenser.
The professional ones are not that expensive but you need an air compressor and I was trying to avoid that extra cost and noise. So I came up with this design.
It uses a PICAXE M14 microcontroller and ULN2003 Darlington driver to run the 28BYJ-48 stepper motor. As a stepper the 28BYJ-48 sucks with its gear ratio, but for this purpose it is cheap and has lot of torque. For my type of work and one-off prototypes it works great.
DIY solder paste dispenser - [Link]
This project is a USB to Serial converter using an ATMEL AVR microcontroller. There are two version of the converter, one with SMD parts and another with TH parts. The mcu used is an ATmega8 and USB communication is done using software on AVR mcu. It’s based on the software USB implementation of AVR-CDC. Firmware can be downloaded from the download section of CDC-RS232.
USB to Serial Converter using AVR microcontroller - [Link]
Just a short video to show how I hand solder a ceramic leadless chip carrier (CLCC) package to a circuit board, in this case, a Si570. Typical surface mount soldering techniques, including the use of flux, fine gauge solder, and a fine tipped iron.
How to solder a leadless ceramic surface mount package - [Link]