DIY LED Art Fan

Use small LEDs for small fans and large ones for large fans.

The LED Art Fan from ThinkGeek contains 42 LEDs that flicker as the fan's blades turn to create moving two-dimensional art. The fan is programmable, so you can create your own images using the included software on a PC. At the time of publication, the LED Art Fan is no longer available, but you can make your own if you have intermediate electronics and programming skills.

Instructions

Design the Circuit

1. Choose a microcontroller chip that provides at least 1kB of memory and the ability to control up to 42 LEDs. The microcontroller's datasheet provides this information.

2. Design a schematic on graph paper or in a graphic design program that allows you to communicate with the microcontroller through your computer's serial or USB ports. The microcontroller's datasheet provides information on how to communicate with it and the required electronic components.

3. Add a power source, preferably a battery, to your schematic. The power source must provide enough voltage and electrical current to power the microcontroller. The microcontroller's datasheet provides this information.

4. Add a Hall effect sensor to your schematic. Connect it to one of the microcontroller's analog inputs. Look at the sensor's datasheet to determine if other electronic components are required for proper installation. The microcontroller uses data from the sensor to turn LEDs on and off.

5. Add a switch to your schematic that turns the entire circuit on and off. The switch stops power from flowing through the circuit.

6. Add 42 LEDs to your schematic. Connect resistors to the microcontroller's outputs, and connect LEDs to the resistors. This prevents the LEDs from burning out.

7. Build the circuit on a breadboard according to your schematic.

Write the Program

1. Launch your microcontroller's programming software. This might be included with the microcontroller or its datasheet might list options. You might have to follow special instructions for preparing your microcontroller for programming before creating your program.

2. Define a variable for storing the Hall effect sensor's incoming data. You may need to create other variables, depending on how you choose to control your LEDs.

3. Set up the microcontroller's input and output pins. The pin connected to the Hall effect sensor is an input. The pins connected to the resistors and LEDs are outputs.

4. Write a program that performs the following functions in a loop: reads the data from the Hall effect sensor, uses the data to switch certain LEDs on and off and uses changes in sensor readings to switch certain LEDs on and off. The LEDs that are turned on and off depend on the images you're creating and the locations of the LEDs once they're installed on your fan.

5. Test your code if the program provides that function. Correct any errors that show up.

6. Connect your computer to the built circuit on your breadboard with a USB or serial cable.

7. Load your code onto the microcontroller.

8. Test the circuit by waving a magnet past the Hall effect sensor and watching the LEDs turn on and off. If the circuit doesn't function as expected, modify your code or circuit.

Build the Circuit

1. Transfer the circuit from the breadboard to a piece of copper-clad stripboard that's small enough to fit on one of your fan's blades vertically. Use your schematic as a guide.

2. Solder the components to the stripboard with a soldering iron. Solder IC sockets, rather than chips, to the stripboard.

3. Put the chips, such as the microcontroller chip, in the IC sockets.

4. Drill a hole large enough to accommodate a cable tie in each of the shorter sides of the stripboard. For large boards, drill a hole in each corner.

Attach the Circuit to Your Fan

1. Remove the fan's grill from the front of the unit. You might need a screwdriver.

2. Measure the length and width of your stripboard and the distance between the drilled holes with a ruler.

3. Mark two to four points on one of the fan's blades with a marker to show where the stripboard is being installed. Use your measurements to determine their locations. Leave enough space between the stripboard and the fan's grill so the stripboard does not hit it as the fan's blades turn.

4. Drill holes large enough to accommodate a cable tie in the marked locations.

5. Secure the stripboard to the fan's blade by running cable ties through each of the drilled holes on the stripboard and fan's blade. Twist or tie the cable tie until the stripboard is secure and doesn't wiggle when touched.

6. Put the fan's grill back on.

7. Align the high strength rare-earth magnet's south side with the Hall effect sensor. The south side might be marked or you can find it by waving it past the sensor and watching the LEDs. If the LEDs react, you've found the south side.

8. Secure the magnet to the fan's grill with glue, cable ties or tape.

Tips & Warnings

• If you've never designed a circuit before, purchase an LED animation kit.

• If you need to decrease the size of your circuit, design and etch a PCB instead of using stripboard.

• Use a small, coin-cell battery to decrease the size and weight of the circuit's power supply.

• If you have advanced electronic skills, wire the fan's switch to your circuit to make it easier to turn the circuit on and off.

• You might get electrocuted if you build or install the circuit while it's powered.

References

• Gizmodo; Review of ThinkGeek's LED Art Fan; Addy Dugdale; June 2007
• Ladyada; Hardware Design for a Rotating LED Circuit for Bicycle Spokes; May 2011
• Ladyada; How to Install a Circuit on a Bike's Wheel; May 2011