Harddisk POV display
Final project for MAS 961 Techniques for Design and Fabrication.
After seeing harddrive POV display projects like Ian Smiths, I decided to give it a try and make my own using a broken harddrive and an Arduino controller.
Process:
- Driving the motors: I first tried to find out how a brushless DC motor operates by probing the signal with a oscilloscope. It turned out they are more complicated to start up and control than I anticipated. Therefore I decided to use the built-in controller instead of designing my own.
- Detecting the motor speed: I used a transmissive photomicrosensor, which consists of an infrared sender and receiver to detect a slot cut into the bottom platter of the harddrive.
- I used surface mount RGB LEDs, which are convenient due to their small size:
- To install the sensor and LEDs, holes were cut into the back of the hdd and the components glued in place with cables leading to the control circuit. Then the original motor control circuit was screwed back on to hold the cables in place and to run the motor:
- This image shows a test of all LED’s turned on (red) with the upper platter not installed. The red circle highlights the location of the sensor. The white tape is at the location of the slot in the upper platter, so the LED’s are more visible:
- The sensor input is analyzed by the Arduino microcontroller to determine the drive speed. The microcontroller then flashes the LEDs to display graphics. The following image shows the Arduino control circuit on a breadboard:
- A slot cut into the spinning upper platter of the harddisk is used in conjunction with the flashing LEDs to display graphics on the device.
- A video of the display showing a rainbow test pattern can be viewed here: http://www.youtube.com/watch?v=bNkj0Uc-hnU
Components:
- 3.5 inch harddrive
- PC power supply with 5 and 12V output
- Arduino Mini 3 with mini USB adapter
- Photomicrosensor: EE-SX1103 (Transmissive)
- 6 pc Full Color PLCC4 LED: OVSARGB3R8 (OPTEK Technologies)
- 3 pc MOSFET: 2N7000 N-Channel 60-V (D-S)
- Resistors: 6*470 Ohm; 12*240 Ohm; 1*330 Ohm; 1*50 Ohm
Tags: MAS962 HDD POV display