laser Harp V2 open and free

[Carl B]

Yes that's exactly what I mean just like how Jarre's harp dose. Sorry for not making my self clear about what I ment.

Carl

[Genesis]

Hi all
some news about the boards:
just 3D models from Eagle3D and PovRay

the sensor one with OPT101 photodiode


and the mainboard in 3d:

[mccarrot]

Wow very nice job

But I see the whole pcb is smd. smd is difficult to solder for DIY. are you willing to deliver complete assembled pcb's?


Keep up the great work

[300EVIL]

Any details on pricing of the bare PCB's?

[Genesis]

Wow very nice job

But I see the whole pcb is smd. smd is difficult to solder for DIY. are you willing to deliver complete assembled pcb's?


Keep up the great work

i know but the V2 was made from standard components but theses one are no longer available in DIP (like D/A converter)
no idea of the price because i need to make samples before.

[FourDee]

I know smd seems harder than thought hole, but once you get started with smd, you will never want to go back.

[T0mmm]

I'd also be interested in a PCB and a box/list of components that i'd need

This project sounds awesome; i'd love to assemble my own one

[Stoney3K]

Cool! So only one PD. I'm guessing each beam is modulated so the harp board knows which beam is blocked. Very nice!

Let a fellow harp-builder enlighten that for you...

The harp is nothing but a one-axis scanning projector (any projector will work, as long as the Y galvo stays put) with the aperture pointing upward.

Detection works through a single photodiode because the PD signal's timing, not its intensity, is important for determining the beam which was struck. After all, a specific timing on the PD corresponds with the galvo position at the moment the reflected beam was received.

The whole thing actually is pretty similar to the electronics inside your keyboard. Instead of a chip having 104 input pins and switches for each key, the encoder does a rapid row-by-row scan of of the key matrix, and by examining the timing on the input pins, it 'knows' which keys were pressed or released.

If the harp was projecting all beams simultaneously, it would be a lot more difficult to make it a frameless harp (with beams going up into the air forever), since it requires a photodiode for each beam targeted exactly at the player's hand. The scanning design is a lot more compact, efficient and allows the PD intensity to be used for a modulation or expression controller.

@mccarrot: I am developing a harp with through-hole components only and an ATMEGA8 as the master brains, and DAC's based on the Microchip MCP4921 SPI 12-bit DAC chip. For the detection, I am using three photodiodes spread over a little wider area (like Jarre's detection system in the World Arena Tour) and a fourth PD which is used for compensation of ambient light.

The detector has a differential output, which means that any detector signal which has both outputs at logic high or outputs at logic low, means the detector is either not connected or at fault. The controller picks that up, and shuts all the interlocks for safety purposes.

[Genesis]

my friend actually work on the website.

http://www.harpelaser.com

but this is just the beginning

[mccarrot]

Any updates on this nice project