The laser harp is a musical instrument with a laser beam "string". When the light beam is blocked, the instrument will play a note. Typically, the laser harp makes the beam vertically propagated vertically with the shape of the sector or vertical line.
In this project, I bundled a laser harp with a horizontally spread stacked laser beam. The beam is reflected from the mirror to form a beam path. The device has a built-in MIDI player, rather than the MIDI output like my previous laser harp, so the output is an audio signal. This means that the sound can be played without connecting the device to a computer or MIDI player (eg, a keyboard). Built-in speakers and audio output jacks can play music.
motivation
I have motivation to create a laser harp that is easier to play. Through this design, the laser beam is falling in "character", which makes it easier to block the audio with a finger. Typically, the light beam is played with the entire hand to play the laser harp, and the performance of this device is more like a traditional string. Aligning lasers and photodetectors is also a big challenge, so my goal is to develop a mechanism that fine-tuning the laser beam direction without the need for alignment.
There are many things to learn from the build and programming equipment to the control motor, Hall effect sensor and rotary encoder from the laser beam. That's why I am very happy to make it a kit. The device is unique because it is located in the intersection of art and engineering, which is usually treated separately, and teaches two ways of thinking, which is very important for design.
I hope that the suite can promote interdisciplinary learning and motivate musicians and engineers to learn coding, electronic technology, and how to play music. After completing the kit, the vertical laser harp has a lasting interactive potential.
System overview
The vertical laser harp consists of 12 lasers and photosensitive resistors arranged in six layers. Two mirrors per layer reflect the laser beam to the photosensitive resistance. In the figure, the red arrow indicates how the laser is reflected to the photosensitive resistance and the corresponding pin connected to the laser and the photosensitive resistor. Because the wiring is sent to the fed tower to the way of Arduino Mega, the pin is disrupted. The laser can be opened and turned on and off, and the voltage drop across the photosensitive resistor is measured using an analog input pin. When the laser is blocked, the resistance of the photosensitive resistance increases and the voltage output is lowered.
This instrument uses a popular Adafruit Music Maker expansion board to generate audio output. I am very happy to find this expansion board because I can easily generate audio signals from the device without having to connect the MIDI player. The expansion board is running in MIDI mode, and the audio output is run to the audio jack and speaker. The latch button opens and closes the speaker.
Use the volume of the potentiometer connected to the Arduino Mega to control the volume of the device. Read the output, the software updates the volume of the MIDI signal. Finally, the device can also switch between different MIDI instruments. Read the rotary switch and use the output update instrument. I have chosen 16 preloaded instruments on the device. The number of instruments is not limited by the Arduino and music libraries. There are more than 100 instruments on the VS1053 chip. I think that if needed, there may be sufficient memory on the board to store all of these tool code. The selected instrument is displayed on wheels with 16 spokes. Use a stepping motor to rotate the wheel, which is controlled by 4 digital pins. The above is my work, thank you for watching.
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Copyright Notice: Circuit City Original compilation, translation from HackADAY, please indicate the source!
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