Laser Harp source code help

i know this might be asking alot, but my self and my senior team hasn't have much experience and knowledge with programming an arduino board.

we're building a laser harp with 10 laser beams and 10 CDS photoresistor. 7 of the laser beams are use for notes and 3 of the beams are for effects, such as reverb, soften and etc.

we already got the arduino to communicate with our software synthesizer (Fruity loops) using a simple program that arduino has given for an example

we're wondering if anybody can help build a program for this particular laser harp. it might be asking much, but it will really help us to get a better understanding and knowledge about how to build programs for the arduino.

thank you

Send me the lasers, the photoresistors, the Arduino, and the requirements, and I'll write the program for you. Hopefully, I'll get it done before you need to turn it in to be graded. Make sure I get credit for the work.

Or, take a shot at writing it yourself, and post the code here, and tell us what problems you're having, and we'll help you get it working. Quickly.

you want me to send the whole project to you? i don't think we can do that....

the whole circuit is compose of 10 cds photoresistor, a high power laser, fruity loops, an arduino board. the arduino board is connected to a 5 pin DIM MIDI JACK just like how it is in here (

we connected the MIDI JACK to our laptop using our software synthesizer (fruity loops)

the main circuit is composed of 3 LM3900N op-am chips. which is connected to our 74150 multiplexer. multiplexer is connected to the TX pin of the arduino board.

we used a simple code from here ( scroll down to see the code in the page.

thank you so much if you can really help us out! i will surely give alot of credit!!

if its easier to talk let me know! so i can call up or give u my number

The best way to get help here is to try writing some code. If/when you have problems, post the code and explain what the problem is.

Some like this:

I've written some code to do whatever:

// Code goes here...

The problem is that I don't understand this, that, or the other. The hardware seems to be working OK (or not). How do I do something (or see what is happening, or ...)?

Then, lots of people who have done something similar can help. Even people that don't understand what you are doing ask questions that help you see the trees instead of the forest.

To rephrase what PaulS is saying (just so there is no mis-understanding):

You should do the work, ask if you have problems and we will try to help, don't ask us to do the work.

While you ask for help writing the program, we can't.
You state you have some lasers, and a midi device or whatver.. and thats it. No info regarding how the hardware is laid out, their datasheets to figure out how you need to operate them, etc. etc. etc.
It would be like driving a car while blindfolded, without even the aid of some terrified passenger telling you where to go.
As PaulS suggested, try it yourself and ask on the forum when you run into something you can't resolve yourself.

Seeing this thread at the top of the News pile and having visited but not contributed in the forum for a very long time thought I'd reply in view of a new thread.

I've been exploring Laser Harps on and off for the past 6 years. I built one a few years back using a PIC micro, some phototransistors, a 150mW Laser, some basic software, glass beam splitters and a hell of alot of elbow grease in building the frame and getting it all going (photo below). I'm now developing a new design. Initially I intended to sell my existing harp frame and laser but wanted a more elegant and safe laser design before flicking it off. So along came Arduino and this is what I have been up to so far:

Existing Features:
16 Analog Inputs - can be extended to 64 easily to cater for all beam inputs, control change sensors.
Laser TTL Blanking/Fail safe/Output reduction via Tamper Switching
Auto Callibrating
LED Array (16 Led Outputs) - used in assigning MIDI events to Inputs and trigger indicators
Cursor Buttons
3.5m X 3.6m Harp Frame (Packs down to very little)

Mark III (on the drawing board):
RGB Lasers, TTL Modulation and Power Monitoring
Shutter Modulation - Allows multicoloured strings + visual trigger feedback
Capacitive, Wind, Ultrasonic Sensing (i.e pitch bend
Adjustable beam patterns
Smaller Portable Frame
LEDs (reverse bias for dual sense and light emission)

Mark III will be something like a generic brain that I can extend or shrink-back depending on the instrument I feel like making which the Laser Harp is just one of many I have made over the years.

I've seen Steven Hobley's Laser Harp design and although brilliant, and as much as I'd love to build something like his design one day due to the cost of getting alot of the required parts to New Zealand I decided to continue to keep things simple and amazingly fast by using Arduino.

As others are saying in this thread, find out for yourself (preferably without burning your retinas out). It has been a real challenge working with micros and electronics and the discovery has been the best part. Our world is full of people that want to short cut the experience and get the t-shirt. From mostly observing the forums over the years it is quite obvious that doesn't happen here.

I'd be happy to start a new thread if the interest exists and share some pics, code etc. as this one doesn't look like it may go much further :sunglasses:

PS: although PIC centered design is a fabulous resource for schematics of pretty much all you need to make a laser harp/midi controller. Replace pots for LDRs...or whatever.

yeah man that is a sweet laser harp and inspired me to build one someday.
ive read that 150mW lasers can burn your hand but i wouldn't want to use a laser that was too weak to easily see.

Also I want to build laser harp? If somebody can help me with link that has important information would be grateful.

Thanks. :slight_smile:

If you shine laser pointer(that is no real laser, but just very bright led) onto photocell Arduino does nothing. When you brake the beam with hand Arduino sends note on duration 300ms and then note off.
This was good starting point for me.

#include <MIDI.h>
byte note = 0;
int valPin = 0; //photosensor on pin0
int val;

void setup() {

  Serial.begin(31250);   // set MIDI baud rate

void loop() {
  val = analogRead(valPin);
   if (val <= 100) {//100 is a number you need to tweak