Introduction: Hard Drive After Life
So your aging hard drive can't hold its data any longer and you replaced it with a new one. Instead of letting it die by the hands of the recycling undertaker, you force it into a new life as a musical noise maker. A dying hard drive makes all kinds of grunts and groans as it starts up. The sounds it makes can be musical and percussive.
This project uses a homemade PIC midi interface to allow sequencer software (Anvil Studio free) to turn on and off eight hard drives. Midi signals are serially transmitted by the sequencer software as sets of 3 bytes at 31,250 baud. A PIC 16F877 has been programmed to receive these bytes to turn on and off solid state relays. Each hard drive needs 5 volts and 12 volts to run. Two SSRs are used to turn on and off the hard drive. I tried leaving on just the 12 volts, then switch on 5v to start the drive up. This worked well for awhile until one smoked up. So I use two SSRs to switch on both 5 volts and 12 volts at the same time. A modified PC power supply is used to supply power. A guitar tuner pickup and computer soundcard amplifies the sounds, making the point that something went horribly wrong with those drives.
Step 1: The Power Supply
You probably upgraded you computer in the past with a larger power supply and its just sitting in your garage getting dusty. You can use that power supply (if its still working) to power this project. Start by locating the +5/+12 connectors that would normally connect to the hard drive. Cut off the connectors and run the wires to a terminal block to make wiring easier. You can get some new connectors at a place like Fry's Electronics to wire up the drives. Black is common (the negative connection), red is +5 and yellow is +12. Below I added a second set of connectors (toward the left) so I can detach the power supply from the project. You will also need a minimum load through the power supply to get it to turn on. I used a 30 ohm/20w and 50 ohm/20w power resistors across the 12 volt output and a 10 ohm/10w across the 5 volt output. A 12v and 6v auto tail light bulb will also work as a load
Step 2: "Bring Out Your Dead" (Monty Python) Hard Drives
Gather up all your old worn out hard drives and plug then into your power supply to see if they will spin. You can remove the covers and watch the platter spin and the head move back and forth. If the sound is pleasing, then its a keeper. Ask your friends or someone at a recycling center if they have some to donate to your project. It is, after all, a "green project" and good for the environment to re-purpose electronic goods. You can use floppy drives too.
Step 3: The Midi Interface
I built my own Midi interface to play the hard drives. The circuit uses a PIC 16F877 to receive midi from a midi card inside a computer and turn on solid state switch modules. Both +5 and +12 volt power is applied to the hard drives. I used the modules because I already had some in a nice rack from a previous project. Transistors or relays could be used to do the same thing. The main idea is to turn on and off the hard drives with midi. I wired the PIC 16F877 and the other components on a Radio Shack pref board.
Step 4: The Software
I like to use free software when ever I can. I found two that will work well with the circuit. Drum Flow v1.70 is one and Anvil Studio is the other. Google the names and you should be able to find them with no problem.
Step 5: Firmware and Hex Files
I wrote the firmware for the pic using Pic Basic Pro. I have the listing and hex file for download at my Blogger site. You can freely use it. If this kind of project is to complicated, you can buy a midi board to interface the hard drives. I saw this one on the web from Highy Liquid. I haven't tried it, but it looks good and is reasonable in cost.
Step 6: What Else Can a Midi Interface Do
I made a drum machine using relays to make the percussion. I call it Purcussus. You can view a webpage about it here. I also have a video at that site of Purcussus doing its thing.
Step 7: The Sounds
Clip on a guitar tuner pickup on the rack and plug into your computer microphone input jack . This will pickup the sounds of the drives as they spin up. The sounds are simply amazing. Go to this link to hear a mp3 recording I made.
Second Prize in the
Dead Computer Contest
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