Off course everybody can order from the factory trough hole plated pcb and they are off the hook, that is the professional solution and for the end product I do the same. But that costs more, there is a lead time and if there is some error on the board or on the schematic, you need redesign and order another one.

I personally use home-made double layer pcb’s for my prototypes, with photo method and some design constraints like track width, spacing,  clearance, the results are quite good.

Yes, that’s nice but it has a lot of vias, and can be painstaking  to make the connections for each via by running  through a thin wire, soldering one end then soldering the other end, cutting down the excess, because for each via you have to handle the wire, the soldering iron, the cutter resulting a great “overhead”. I admit this was my solution and took hours to make each via separately, until somebody showed be a clever trick, but that’s enough talking, here are the pictures:

You need some thin copper wire:

First anchor one end of the wire by soldering to one side:

Run through the vias(like sewing) the wire:

Solder each end:

Start cutting as close as possible(on each side):

The result:

Nice, round bumps

And after soldering the TQFP package:

As you can see, the vias underneath the TQFP doesn’t cause any problem, although more attentions is needed when soldering. Fast and simple, hope you get the spirit and start tinkering.

Here is the schematic of the charger:

After ordering the needed parts I noticed that the  inductor is slightly bigger than I expected it to be, so fitting the board into a small box became a bit of a problem. But I managed to designed the board so that it fits into the chosen box. I also fitted a medium sized TO-220 radiator so the circuit would dissipate the heat even in continuous use of the charger. The pcb was made using the photo etching technique and I tried spraying it with a mix of colophonium and alcohol that would act as a soldermask. The result is not pretty but I hope it will protect my board from corrosion.

After the soldermask dried it was only a matter of minutes until I assembled and tested it. The charger works great, the output voltage remains constant over continuous variations of the input voltage. Now all I have to do is close the box, solder a cigar lighter connector and pack it into my arm rest compartment.

In response to the high interest shown by the readers on a spectrum analyzer posted here I decided to make a new design, that will be available in shop as a kit. The movie shows just a stage in the developing process, where the filters were being tuned. The final design will be powered by an atmega64 and will have 20 bands with 20 LED’s on each band.

I am now searching for a pcb manufacturer to get a good price on manufacturing the boards, then it will all be ready.. stay tuned.

new pcb from bkrtech that is gonna be used for AVR DOPER programmer

new pcb from bkrtech that is gonna be used for AVR ATmega640 dev board

new pcb from bkrtech that is gonna be used for AVR ATmega64 dev board

Some of these projects will be submited here on Youritronics for more free PCB’s , i only hope more of you join the program because, there are more free pcb’s to be given.

Of-course there are other projects based on this idea around the web, but what makes this one special, it’s he’s features. There are 3 stepper motors controlled by a single ATmega8 that runs at 8 MHz, and a motor driver for each motor. The motors and their drivers were recovered from an old printer.

Although the motors are controlled by the same microcontroller each one can move independent. The board can receive commands to drive the motors trough serial interface from a computer. There is also a PC software that enables you to send commands from a nice graphical interface.

As you can see this is a very practical application, for example it can be easily developed into a CNC machine. I personally like morgoth’s coding skils and i think he has some more great projects to show.

And in the ending here is a movie with the motors in action.

Here are some downloads:

• asm source, hex, and board files
• source files for pc interface
• pc interface.exe
• pcb picture
• schematic picture
• NOTE: youritronics reader Radu pointed out that the schematic is wrong. According to the datasheet the Atmega8 has GND on pin 3 and 5 and VCC on pin 4 and 6. The schematic has the VCC and GND the other way around, you need to correct that for the system to work.

I made the board using my photo etching technique, and as you can see the results are great. The dev board has 17 I/O lines that are connected to a 17 pin header. On the board there is a 2 color LED tied to PortC pin 1 and 2. On PortC pin 0 there is a PNP transistor that controls the output for a buzzer. So i always use pin 0 to connect the buzzer.

There is also an ISP connector on the board to be used for ISP programming, and an extra VCC pin so you can get power from it. I power my board with 2 AA batteries which provide enough current for testing purposes, but to ensure you’ve got enough power you should probably power it from 3 x AA batteries to get 4,5 V.

Here are a couple of source codes that i developed on this board:

This one makes a beep for 5 seconds than stops.

And this one blinks the two color LED.

I’ll be integrating these codes in a larger project. All codes are written in C and the board was designed in Eagle, here are the download links:

• Buzzer.c download link
• Blink.c download link
• Eagle files download link

The title is pretty straightforward, it’s time to give something back to my readers. Inspired by the Giveaway project from uChobby i created my own giveaway project the main difference is that instead of parts for projects i offer PCB’s for projects, professionally designed PCB’s. Our sponsor for this program is BKRtech, a professionally board manufacturer.

I hope you’ll find this interesting and participate. The program page is here.

The project is dedicated to helping people build a high performance sealed lead acid battery charger. The project is also available as a partial kit with a custom made PCB. However, there is also enough information for you to build your own PCB (or use Vero board) or change the design to suit your own purpose.

Lead Acid Battery Charger: [Link]

The schematic shows that wiring the LCD to the HEF4094 is a simple operation. It has been drawn in a way that makes possible to develop this as part of a single sided PCB including a variable resistor to control the LCDs contrast. Note that the pinout of the LCD module may differ slightly from the pinout depicted; some LCD modules have pins 15 and 16 on the left side, before pin 1.

3 wires interface for LCD display: [Link]