IHarp

Learn how to turn a cheap plastic harp into a fancy iHarp! Simply add a led strip driven by a microcontroller to make the harp an eyecatcher.

You can use the following parts:

• A harp (plastic or a real one if you want to go fancy :D)
• ATTiny 85-20PU microcontroller
• Resistor 470 Ohms
• LED strip with WS2812B diodes
• Breadboard
• Battery case with on/off switch
• Cable ties, double sided tape, tape

Tools:

• Soldering iron
• wire stripper (or a knife or scissors)

Assemble the microcontroller, the led strip and the battery case as shown on the drawing. I used some leftover breadboard. I recommend putting the microcontroller in a socket - this way you can easily reprogram it. Make sure to attach the data line onto the input side of the led strip, it's usually labeled Din or similar.

There are some great instructables out there on how to program the ATTiny. I recommend this one by fellow instructables user danasf: USE A $1 ATTINY TO DRIVE ADDRESSABLE RGB LEDS It also includes a link to Github where you can find a working example. I stripped this example a bit by removing the button support and hardwiring a fix pattern to be shown by the leds.

If you have an Arduino Uno board you can use it as a programmer for programming the ATTiny. Check out these great instructions on details how to set everything up: Programming ATtiny85 with Arduino Uno

Stick the led strip to the harp. I added some cable ties because I didn't trust the glue. Run the wires to the backside and along the harp to the bottom. I used some brownish tape which matched the harps color quite well. Using some double sided tape stick the battery box to the harp. Again I reinforced with some cable ties.

Flip the switch and enjoy the light show!

Enhancements:

• Add a button and cycle through different patterns - check out the example code referenced in step 3.
• Add a shake sensor or gyroscope and cycle through different patterns accrodingly
• ...