Monday, February 25, 2013

BabyBOOMER Audio Amplifier and Filter Prototype for Arduino/ChipKit

Here is a prototype of one of my circuit boards for the planned BOOMstick Audio board family. This series was introduced in my previous post. It is intended for use with Lutz Lisseck's SimpleSDAudio Arduino library and my port of that library to ChipKit, BasicSDAudio. Really, it should work for any PWM-based audio system, including the Tone library.

Top side of the BabyBOOMER Audio board prototype
Here are the goals I was trying to meet with this board:

  • small (only 0.56 sqin)
  • breadboard friendly (basic 0.1" headers)
  • at least 1W speaker output using 8ohm speaker (efficient class D amplifier)
  • easily accessible volume control (right out on top)
  • lower PWM noise including buffers, filters, and a pseudo 16-bit mode

Bottom side of the BabyBOOMER Audio board prototype
I did a preliminary test just running the ToneMelody Arduino example sketch with a 4ohm speaker. It was *very* loud for such a small board. I had to run off a battery since my wimpy USB cable cannot reliably supply 5V with the estimated 2W output using a 4ohm load.

Time for some real testing!

Sunday, February 24, 2013

$65 RAMPS 1.4 Boards Available Soon!

I will soon have RAMPS 1.4 fully assembled circuit boards available for sale on my Store page. 

The price will be $65 USD with free shipping!

RAMPS 1.4 with only SMT components mounted. $65 price is for the fully assembled board.
This board is used along with an Arduino Mega (or compatable) and Pololu Stepper drivers to create the most common 3D printer controller.

I expect to start sales in the next couple weeks, so stay tuned.

At least for now, I am only prepared to make sales to US customers. If you are outside the US and interested in this board, please vocalize your desire in the comments section.

*Assembled in USA*

Saturday, February 23, 2013

Prototyping with OSH Park

Thanks to a tip from an awesome open source project (FreeIMU) a few years ago, I started using DorkbotPDX for circuit board prototypes. Since then, Dorkbot consolodated its PCB fabrication service onto a dedicated site,

For a flat area rate and free shipping, you can get professional grade circuit boards that not only look good, but are easier to assemble than homebrewed options such as etching or routing. You pay $5 per square inch for 3 copies of a two layer board and $10 per square inch for 3 copies of a four layer board.

I wanted to test some mosfets that I found on Digikey for use with an outdoor laser tag system I am working on. I drew up the circuit and layed it out in Eagle, exported the gerbers and uploaded them to OSH Park.

OSH Park Order Page
$1.20 and two weeks later, I had 3 boards in hand, ready to solder.

My MOSFET_breakout board ready for breadboard testing 
OSH Park can deliver such great rates for prototype PCBs because it is a panelizer. It collects dozens of different PCB designs in order to fill a much larger panel. This mosaic panel is what is sent to the PCB fabricator. When the panel comes back from the fabricator, it is broken up and sent to the correct addresses. This effectively gives everyone on the panel a quantity discount, even if their order was only a few square inches.

The quality of the boards is superb. If you are looking for prototype PCB service, use OSH Park!