Laserharps Pre-order!

[csshih]

has anyone gotten their kit up and running? I love seeing pictures and videos

Craig

[Carl B]

Hi Craig

I have got mine up and running and it's bloody brilliant to play.
I have a 400mW green in it at the moment but has a problem with mode hopping at times. I hope to be fitting some 445 Blue at the UK LEM next weekend.
I am taking it to the UK LEM next weekend and hope to get some decent video of me playing it then.
I will post some photo's ASAP.

Anyone still thinking of buying one of these kits, stop thinking and do it. They really are great kits.

Carl

[Carl B]

Here is a photo of my harp in action.
DSCF6106.JPG
Note the mandatory white gloves on the keyboard.

I have been playing with positioning the sensor and have found that the sensor on a standard tripod between the harp and the person playing it seams to be the best setup at the moment. Jarre sets his up this way on his indoor tour at the moment.

Will get some video at the UKLEM next weekend.

Carl

[Stoney3K]

What's everyone's best solution to prevent scatter and background lighting from triggering false positives?

When I'm using my harp at home with a white ceiling, the sensors can't get a decent SNR because of the scatter coming from my own laser and the ceiling above. Would it help to offset the sensors at an angle and maybe even use something like a lens to narrow their detection area down?

[Things]

Stoney3K, yes, I have put them in a fairly deep box with a slit opening. This way the sensors are focusing on only a certain section of the beams & not the ceiling.



16 of these kits left I believe! Most likely the last run, so if you've been putting it off, probably the time to go ahead

Also, everyone who has a kit from the first batch, please don't forget to email me (And include your forum username) for the 2.45 code update!

[Bradfo69]

PM sent.

151515151515

[csshih]

=) laserharps. you know you want one.

C

[kiyoukan]

So any one who made these got a spare galvo?
I tried my spare 20k set on mine and the pattern is small.
We are working on a solution but still nothing yet.
So if someone has a single galvos that can run from a 15+- psu that they would not mind letting go of please message me.
USA only please, for fast shipping.

[SoulFeast]

To go from nothing to Mozart, how much dough do I need to shell out?

[Things]

Hey guys, for those of you with a harp that don't check back on the LPF thread, I am planning on doing a software upgrade to allow multi coloured beams within a few weeks.

If you still haven't updated to 2.45, please don't forget to email me!

Dan

[Carl B]

Hey Dan

good to know you are still working on and tinkering with the code for the laser harp. multi coloured beams, sounds interesting but I'm going to stick to the way my harp is now as it's the way Jarre's harp functions.

The only thing that I would like to improve is to try and match the brightness of the beams when opening / closing with the beams in play mode.
If this is just a case of changing the values of a couple of lines in the serial monitor this would be great but if it's a bigger job then it's not that big of a problem to me.

It may be less of a problem when I finally get round to fitting the 445nm with it having faster modulation abilities. Yes, I still have not got round to fitting this in with the green.

Carl

[dnar]

* Marked for subscription *

[csshih]

harp kits are quite easy to solder! I got bored this evening/morning and decided to solder one up for myself. woohoo, fumes!



Kester Sn61Pb36Ag2 Solder - good stuff! I cleaned off the rma flux to make it look nicer

Craig

[dnar]

A have a question regarding operation. Is it Monophonic or Polyphonic?

[Carl B]

This laser harp kit is polyphonic.

[Things]

Only ONE of these left!!

EDIT: All done and dusted with batch 2! No more now unless there's enough interest. Thanks to everyone who has purchased!

I will still be doing code updates, so check back every now and then!
Dan

[dnar]

Hey Dan, my kit arrived yesterday, thanks!

BTW, firmware 2.45 is the most current yes? Is this what my MCU will have loaded?

[Things]

Glad you got it

Yes, 2.45 is the latest currently, your MCU should have that on it, though shoot me an email if it doesn't and I'll send you the firmware updater.

Cheers,
Dan

[dnar]

Cool thanks.

Say, what are the chances of me getting the source code? I am willing to either "keep it confidential", or offer back improvements or what ever. It's just that I have some specific needs to add things and also to tweak the design to improve sensor performance.

If not, can you at least provide the MCU port I/O details so I can write my own code from scratch? I could reverse engineer a schematic and will do if I must, but it's easier if you can provide the info I require.

Cheers. Wayne Jarre.

[dnar]

Sorry for the double post.

Things, I have built my kit and have it running after a bit of debugging the hardware...

A few comments:

1. The documentation needs to add that the LCD R/W pin (5) needs be grounded (pin 1) for the LCD to function.
2. Can I please have the source code, I want to make some improvements?
3. The first beam modulation duration is longer than the following 9 beams.
4. The modulation signal leading edge has jitter, visible on the scope.
5. The scanner output is not fully symmetrical, -5v to +4v approx. I would like to correct this if possible, can I please have the schematic in pdf format?

Ch1 (Yellow): Scanner output (single ended)
Ch2 (Cyan) : Modulation output

DS0063.BMP

[csshih]

Dan's had some spotty 'net connection so I'll see if I can get in touch with him


Craig

[dnar]

Thanks. More questions.

At some point yesterday I had "Calibrating..." on the LCD, but I am not sure how I managed to get into this mode. There is an almost total lack of "user documentation" for the software. Can you provide this please?

Also, using a 300mW 445nm laser, I have found the whole detection system to be very poor. I would love to see the schematic and software as I am sure I can improve this substantially. Question: is the software sampling the ambient light level just prior to enabling the laser modulation, then looking for a delta once the laser is on?

As it is this will be useless for what I have planned.

PS.When the harp is closed, the scanner is "parked" at full deflection. I would like to change this to be "centered" (less heat).

The modulation looks less than ideal on my DSO. The modulation signal could be enabled for each beam much sooner than it is also, visible power is being lost. This could be a user tunable.

Also, per bank MIDI channel definitions would be great, so I can change "instrument" not just notes....

Another issue I have noted, the beams get brighter when triggered, this tells me the main line code is doing most of the work and the modulation is extended due to additional processing. I would have implemented this with a timer interrupt routine to produce the scan and modulation signals... Out of interest, does the code use the Arduino boot loader and DigitalWrite routines, because that IO method is SLOW!

This is one "kit" that access to the code and schematics would be great, as I am willing and able to improve this quite substantially. I see no need to protect any IP here, as it's not about the money right?

I am getting closer to simply reverse engineering the schematic and writing better code from scratch...

[Things]

Thanks. More questions.

At some point yesterday I had "Calibrating..." on the LCD, but I am not sure how I managed to get into this mode. There is an almost total lack of "user documentation" for the software. Can you provide this please?

This is kind of a useless mode, I was intending to remove it from the latest firmware but forgot about it.

Also, using a 300mW 445nm laser, I have found the whole detection system to be very poor. I would love to see the schematic and software as I am sure I can improve this substantially. Question: is the software sampling the ambient light level just prior to enabling the laser modulation, then looking for a delta once the laser is on?

The software should never see any ambient light level, as the opamp circuitry is designed to only detect quick pulses of light. Using it under LED or fluorescent lighting would be an issue here, there isn't really much yo can do about that other than putting wavelength pass filters on your sensors and avoid using lighting of that colour (If you're on stage, for example).

Then again, 300mW of 445nm really isn't all that bright. The sensor is fairly centered around green for best detection, there is a good chance you simply don't have enough light for a solid reflection.

As it is this will be useless for what I have planned.

Seeing as I haven't done any more runs on these, you could easily sell it again for what you paid, if not more now that it's assembled.

PS.When the harp is closed, the scanner is "parked" at full deflection. I would like to change this to be "centered" (less heat).

I have noticed this too, and am looking at ways of dealing with it.

Also, per bank MIDI channel definitions would be great, so I can change "instrument" not just notes....

Have been planning on adding this functionality, however no one has really bothered asking for it so I put it on the backburner for a while.

Another issue I have noted, the beams get brighter when triggered, this tells me the main line code is doing most of the work and the modulation is extended due to additional processing. I would have implemented this with a timer interrupt routine to produce the scan and modulation signals... Out of interest, does the code use the Arduino boot loader and DigitalWrite routines, because that IO method is SLOW!

Correct, however the harp does already use timer and hardware interrupts. The issue here is we only have 1 core to work on, and sending the MIDI messages are what takes the largest amount of time in the code.

Yes, it does use the Arduino bootloader, however it uses portmapping instead of digitalWrite for better speed.

This is one "kit" that access to the code and schematics would be great, as I am willing and able to improve this quite substantially. I see no need to protect any IP here, as it's not about the money right?

Not so much the money, but the fear of my work being leaked. I have been very reluctant to share the code as I have spent many days and nights working on it, and I'd hate to see someone just spreading it around. It also means I'd get constant messages asking why their DIY system isn't working, how to fix the code, what the code does, explain the code step by step etc etc. Much easier if I know the hardware everyone is working with, thus why I ran these kits.

I am getting closer to simply reverse engineering the schematic and writing better code from scratch...

If you feel you really need to, go ahead, but I've never had anyone bring up the requests/issues you are, so there was never any push for me to change it.

If you can write out a complete, straight to the point list of what you want/want changed, I'll look into it. I have some spare time coming up I could deal with it in.

[dnar]

Thanks. So no chance of getting the source under an nda? How about I send you my code changes and you continue to release with my improvements?

I am offering you code improvements by someone with years of embedded real time experience.

You didnt reply to question re ambient sampling ?

[Things]

I've sent you an email.

Dan