Shepherding electrons

Atmega328 as an external EEPROM programmer Need extra memory for an AVR project, but don't want to splash out on a expensive EEPROM chip programmer?  It's easy to build your own! The problem: You need additional EEPROM memory for an AVR project, for example to hold data that wouldn't otherwise fit in the native AVR's EEPROM.  But how to get that data onto the external EEPROM?   The solution: Well... y ou could use an EEPROM programmer, but they can be expensive, and besides, you probably only want to write a few chips and it feels like overkill.   Why not use your AVR to accept data from your computer and then burn it directly onto your EEPROM chip? PC --> AVR communication with USART The easiest way to get your AVR to talk to your PC is to use a USB USART converter.  I picked one up for next to nothing. The one I got was a CP2012 STC.   To use it, hook up the USB TX line to the RX pin on your AVR, and the RX line to TX pin on your AVR.  There are als

Interfacing a microSD card with an Atmega328 microcontroller Hooking up an SD card (or microSD card) to your AVR project will seriously increase the amount of data storage you can access.  I wanted to stream WAV files from an SD card for an audio project I was working on.  I'm not going to delve into FAT16/FAT32 architecture or the SD card SPI interface in this post, but working on the principle that Life's too short to reinvent the wheel, there are libraries available for reading and writing to SD cards with Atmel microcontrollers.  First things first, we need to physically connect our SD card to the controller.  I'm actually using a microSD card to save space on my PCB, but I'm using a microSD card adapter so this will apply to SD cards equally.  Grab a soldering iron, your SD card (/microSD card adapter) and a 7 pin header and solder like so: Tin the header pins and be careful not to melt the plastic and bridge the connections.  Using a putty like "

I was looking for a way to drill holes in home-made PCB boards.  It seemed that my only option wa investing in a rotary tool (i.e. Dremel) with a drill press.  However there seemed to be many forum discussions where a slight swing of the drill bit during lowering the drill press was causing a misalignment of drilled PCB holes.  Then I came across small 12V motors that had a drill bit attachment. Some have made their own drill presses for this.  Search Ebay or Amazon for "pcb drill press" and you'll be able to pick one up for a few pounds/dollars.  I soldered a small button onto the side of mine and, lo and behold!  A working, hand held PCB drill!  It's easy to find sets with the motor, drill attachment and several drill bits.  I found one with a set of 2 x 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4 and 1.5 mm bits. So how does it fair?  I've hooked it up to a 9V battery and hey presto...: Those are mostly 1.0 mm holes I've drilled there and by my eye they loo