Stoney's First Build - 0,6W RGV with harp mode!

[Stoney3K]

At last I have the time and the chance to start building my own projector, I had to postpone the project earlier due to space limitations.

The unit will be powered by a 50mW New Wish 532nm green module, a 300mW 650nm red can diode and a 250mW 405nm Blu-ray diode. The latter two are still on the way, as are the Laserwave dichros I'm going to use with them. I expect them to be in by late next week, so I can make some nice white beamshots!



This is the enclosure that's going to be used for the projector, the gutted corpse of a dead Nortel Baystack 350 Ethernet switch. I still need to grind some bits off like the slot for the uplink module (near the front) and the PCB standoffs, and I'm curious as to whether the height of the unit (1,5U) will be enough to accomodate all of the hardware.



I started work on the beam table today. I used a polymer composite plate here I got from the local hardware store, and made a sandwich of two layers epoxied together totalling 12mm of thickness. This stuff is tougher than aluminium, is non-conductive (so I can bolt everything straight to it) and is OK to machine. I'll be getting a tap kit tomorrow, when the resin has set, so I can mock up the position of all my parts and drill/tap the appropriate holes.



The DHL van parked in front of my door today, with a very nice gift: A 20kpps galvo kit with matching amplifiers and PSU. Plug and play. Still, there's some work to do here putting it all together and aligning everything.



Meanwhile, the DAC is getting it's own home with this salvaged data transfer switch, the hole where the knob is is just big enough for my remote interlock key, which will be joined by a few LED's to indicate the interlock is active and the loop is closed, and an emergency stop switch. There's plenty of room on the inside for the USB sound card and the Laserboy amp board, and maybe even a 230V power supply so I don't have to lug around wall warts.

More pictures of the earlier unit on my Photobucket album, which was using the 50mW green with a stepper motor. I'm switching to galvos because I want to make the unit more versatile, and to make detection a lot easier.

The laser harp function will be controlled by a laptop and a Wii Remote for detection. 300mW of cyan (or 600 of white in really large venues) should be more than enough for the thing to pick up, the 50mW green might not cut it on its own.

[Doc]

Congratulations on your build start

That composite laminate board really is tough stuff, I used it as a base plate for a double red module.

Looking forward to seeing this progress.



Ian

[Stoney3K]

Congratulations on your build start

That composite laminate board really is tough stuff, I used it as a base plate for a double red module.

Yap, and it's heavy too. This thing's not going to shift that easily, only if I really want it to...

Hey, it's not exactly a slab of granite, but close enough. I wouldn't want to be hoisting a projector with a granite base up a truss anyway...

[Jem]

The laser harp function will be controlled by a laptop and a Wii Remote for detection. 300mW of cyan (or 600 of white in really large venues) should be more than enough for the thing to pick up, the 50mW green might not cut it on its own.

Are you making the Laser Harp sensor yourself?

If so, are you using Steve Hobley's design or do you have your own design?

Jem

[Stoney3K]

Are you making the Laser Harp sensor yourself?

If so, are you using Steve Hobley's design or do you have your own design?

Jem

I'm just salvaging the camera from a Wiimote, Stephen uses a dedicated photodiode but I have no clue as to which unit I should use in that case.

The light should be more than bright enough for the Wiimote's camera to pick up, if it's not, I can always design a different front-end later.

I'm separating the controller from the projector unit itself, the projector will have an aperture on the front like any regular unit, and I'll use a bounce mirror to make the beams point straight up. In theory, the controller should be nothing more than a laptop with a Wiimote and the DAC connected to it, and some bits of software.

[mliptack]

From my limited understanding of how Wiimotes work... the 'pointing' capability is based upon IR. The remote outputs an IR signal (you can test this by pointing the front end at a digital camera, you will see a blue-ish-green glow) and the WiiTV sensor has 2 receivers spaced about 6-8" apart. Using those two sensors the Wiimote can figure out exactly what you are pointing at...

If there is a camera in there, thats news to me, and could be pretty cool for some other projects too.

Good luck with the projector. I assume you have done your research on the Wiimotes and know what you are dealing with. At any rate, I hope this works out! I am sure it will look great!

[Stoney3K]

From my limited understanding of how Wiimotes work... the 'pointing' capability is based upon IR. The remote outputs an IR signal (you can test this by pointing the front end at a digital camera, you will see a blue-ish-green glow) and the WiiTV sensor has 2 receivers spaced about 6-8" apart. Using those two sensors the Wiimote can figure out exactly what you are pointing at...

If there is a camera in there, thats news to me, and could be pretty cool for some other projects too.

Nope, it's the other way round: The Sensor Bar is just a set of infrared LED's (2 on either side) and the remote has a camera SoC which tracks the position of those LED's in relation to the remote. Since the LED's positions are supposed to be fixed (on or under your screen), it can determine the remote's position in relation to the screen.

The camera is sensitive to visible light as well as IR (just like any other video camera) and tracks the position of reflected blobs in hardware, and outputs them on the Wiimote's internal I2C bus. The remote is fitted with an IR filter on the front which prevents false positives from the surrounding light and the TV, the filter is easy to remove and makes the Wiimote sensitive to all visible light, including lasers.

[Jem]

Wow, cool stuff .

If you don't mind keeping us informed as you progress...

I'm sure i'm not alone when I say that there are many of us who would love to be able to double up our projectors as laser harps

Cheers

Jem

[buffo]

The Wiimote is actually a very useful little device. You can use the camera in the Wiimote with a pair of LED's mounted on a lightweight pair of eyeglasses to track your head movements and generate a true-perspective 3D world on a computer monitor. See Johnny Chung Lee's project page (third one down) for details.

For those of you who attended FLEM version 3, remember that Aaron Bacs had this exact setup running on his laptop at the back of the room. Cool stuff!

Adam

[Stoney3K]

The Wiimote is actually a very useful little device. You can use the camera in the Wiimote with a pair of LED's mounted on a lightweight pair of eyeglasses to track your head movements and generate a true-perspective 3D world on a computer monitor. See Johnny Chung Lee's project page (third one down) for details.

My plan is to project the harp with the regular projector (through plain ILDA), and of course bounce it upwards, and aim the Wii Remote's camera at a 30-45 degree angle to that.

If the camera were 'looking' straight up, it would generate a lot of false positives, from fx. the beams reflecting from the ceiling. I only want to pick up the reflection from my hand. Mounting the Wiimote at an angle also enables me to pick up the height of where I touched a beam, so I can use the height channel for a second controller like modulation.