rocketnumbernine

Andrew's Project Blog: Hardware, Software, Stuff I find Interesting

Posts in category 'howto'

More and more interesting devices seem to be using 3.3V rather than the usual 5V that micro-controllers run at ...
The Serial Peripheral Interface - SPI - allows digital devices to communicate using only 4 wires, additional devices can be added to the same 'bus' with the addition of only a single selection wire for each device. There are many integrated circuits and other devices that can be controlled via SPI, this entry details a simple experiment with a MCP3201 12-bit Analogue to Digital Converter. Background Each end of a SPI connection is acting in one of two roles - Master or Slave ...
This is a follow on to "Using SPI on an AVR (1)" and illustrates using SPI to communicate with a real time clock chip, it also illustrates use of external interrupts to initiate code on the microcontroller. Maxim DS1305 Real Time Clock The DS1305 Serial Alarm Real-Time Clock is an 18 pin DIP clock chip ...
I've been asked for the code used to read the MAX6675 Thermocouple-to-Digital Converter used to measure the temperature in my ongoing SMD Reflow Oven project ...
This is a follow up to Using SPI on an AVR (1) and Using SPI on an AVR (2) articles which illustrated using an AVR Microcontroller to communicate with some simple SPI Slave devices. This entry shows two AVR Micro controllers communicating with each other through SPI - one acting as Master and one as Slave ...
This article details a simple approach to decoding the output of a 2 bit incremental Rotary Encoder ...
Looking for something interesting to reach the minimum value on a component order, I picked up a couple of Maxim ICM7128 LED drivers, actually I got some Intersil ICM7228 which is interchangeable ...
I don't have and have never really had the desire for a signal generator, but have wanted to play with the [AD9851 DDS chip][AD9851] (a digitally controllable 0-180MHz sine wave generator) for awhile and managed to win an [ebay][] auction for a "AD9851 Module DDS Signal Generator with Circuit Diagram" for $23.50 including shipping from China to Europe, that's cheaper than [digikey][] charge for the chip alone! AD9851 DDS Board The board arrived in less than a week and was marked as "valued at $3" so no customs were charged ...
I was fed up with creating gerber files through the Eagle GUI and bundling them up manually before sending to get manufactured so created a shell script. It's not rocket science but I couldn't find that much help on the internet so the following may help others figure it out faster - have briefly tested in Eagle 6.0.0 and appears to work the same as 5.0. Eagle gerb274x cam file screen Gerber files, for example the top copper *.cmp* gerber file (created using the gerb274x cam file in Eagle pictured above), can be created from the shell using the following: eagle -X -dGERBER_RS274X -oboard.cmp board.brd Top Pads Vias Where Top, Pads, and Vias etc ...
I lost my AVR GCC installation on the upgrade to OS X Lion and I can't remember where I got the previous version from. There's [CrossPack](http://www.obdev.at/products/crosspack/) and [OSX-AVR](http://sourceforge.net/projects/osxavr/) binary packages, and you can compile the tool chain by hand to get the latest version (for example, see [Option 3 at ladyada.net](http://www.ladyada.net/learn/avr/setup-mac.html) but you'll need to apply the latest gcc patches). [MacPorts](http://www.macports.org/ports.php?by=name&substr=AVR) can download, compile, and install AVR GCC 4.0.2, but since moving to [Home Brew](http://mxcl.github.com/homebrew/) for other application installation I was disappointed to find there isn't an official AVR GCC formula yet, but as luck would have it [Lars Immisch](https://github.com/larsimmisch) has written a set of formulas to install GCC 4.6.1, they haven't been pulled into the main Formula repository yet so the simplest way to install is: git clone http://github.com/larsimmisch/homebrew-alt.git brew install homebrew-alt/avr/avr-libc.rb If you don't have brew check its [homepage](http://mxcl.github.com/homebrew/) for installation details (a one-liner) avrdude is available in the standard formula set: brew install avrdude --with-usb ...