Have a look at ide64.org and news.ide64.org to learn more about the hardware and related projects.
In short, the IDE64 is (as the name suggest) an IDE controller for the Commodore64, it makes it possible to attach IDE harddrives and CD-ROM drives and provides another expansion port that can be used for an Ethernet card.
I have a few C64s, but the one I use the most, is a C64C, and decided to build the harddrive and power-supply into a dead 1541-II drive, I was not too concerned with safety and craftsmanship back then, so it's not extremely well-done, but I guess it's still fun enough that I should put it online.
Formatting the harddrive
The assembled drive, I used screws that were too large to secure the fans, bending the top vents, shame.
The back of the drive turned out well enough, an old CD-ROM drive donated the connector for attaching the slave, so I can attach a CD-ROM drive or another harddisk for backups.
How it looked before it was put together, the power supply board is from an AOpen ATX PSU, it's runs quiet enough, but lacks shielding so unfortunately, you can not put a this drive on top of a 1541, it will fail and corrupt read and writes.
Tight fit, but it does fit!
Cut and soldered an IDE cable to the cut CD-ROM drive PCB for the slave.
Connected to the IDE cable.
Those two little fans are running at 5v, they are quiet enough.
The power and status indicator LEDs are connected like this, IDE pin 39 floats when there is no disk activity and is grounded when there is activity.
Internets! Actually, the IDE64 is not very usable for accessing the Internet, IRC works well, and it's possible to run a webserver, but the card shines for a different application; Making any PC act like a giant, speedy floppy drive!
When running the ideserv software on the PC, it can be accessed as drive 15 (or whatever you configure), making it possible to read and write files to and from the PC, and transfer files between floppies, harddrives and the PC.
A C64 with 10 GiB Harddrive and Internet.
Attached to the case by heating standoffs and pushing them into it (duely regretted).
Google worked, don't know it it still would.
Attached to the machine (I regret the bad job I did of that).
Testament to the age of this project, these pictures were taken later with my, at the time, very modern cellphone.
With CD-ROM drive.
The slave connection.
File manager built into the IDE64 firmware.
The Final Cartridge 3.
Commodore Toolbox Cartridge had a very cool tool for adjusting azimuth on the tape drive.
Well, it's something I have. ;-)