Welcome to another edition of Openschemes’ teardown and review series. Sadly, our normally venomous and sarcastic reviewers have been impressed into saying mostly nice things about the device in hand, although it could be that they’re extremely susceptible to the pew pew goodness of low-cost laser shows!
The device under investigation will be the CASA CTL-BM RGV Laser Show. This is a 3-beam laser projector with Red, Green, and Blu-Ray Violet lasers. It’s legal status for commercial use is doubtful at best, and the safety aspects are extremely suspect due to the use of DPSS green and Blu-Ray Violet lasers. But it looks freaking fantastic and is quite a treat to poke around inside one. The cost is about $200 USD, available on ebay and other web sellers. That money comes directly from the ad revenue of these pages, so we thank our users for disabling Adblock on these pages, and hope the ads are relevant and interesting enough that they are not annoying. We’d like to hear your feedback on the subject in The Forum – Ad Thread.
Today, we will disassemble and analyze the construction and operation of the CTL-BM in hopes of bringing new knowledge to those users that want to build their own RGB (or RGV) laser show. It’s such a cool application, and such a serious undertaking, that it really helps to see just what makes those commercial models tick. If for no better reason than to prove to you that it is within the capability of the homebrewer. We hope that you gain some knowledge, sprout some new ideas, and get inspired to go out and make something fantastic. Please leave us your comments, especially if you’re starting a project of your own! You can discuss this project on The Forum – Lasershow thread.
The projector is an RGV model, meaning that it combines 3 separate laser beams (Red, Green, Violet) to produce various colors. This color palette includes the highly desirable “white”, although since the blue beam is actually violet it is not a true white and is referred to as “silver” by the manufacturer. But it still looks pretty white, especially when scanning around and switching between colors. This device is intended to be a small standalone laser show for parties or dance clubs, and seems that it would work well for smaller venues, especially with the use of a fog machine to make the beams visible. As previously mentioned, the device is probably not legal for and is certainly not FDA approved for commercial use in the US, so don’t take our positive comments as incentive to use this device for anything other than your own personal enjoyment at home.
The CTL-BM contains X-Y stepper motor drivers so it can control the direction of the beam over about a +/-45 degree angle in both the horizontal and vertical directions. It includes pre-programmed projection patterns and has a small microphone to sync the display to whatever music is playing. The manufacturer states 100 patterns and 500 laser effects in all. This include both static patterns such as a steady circle or square, or dynamic patterns such as an expanding circle or wiggling sine wave. Plenty of stuff stored in there, and it’s great that it’s able to run in automatic mode, synced to the music in the room, or via DMX control. Good stuff!
Let’s take a look at a classic laser show effect, the “tunnel”. This pic is from the manufacturer’s ad for the device.
Manufacturer’s Representation of the Device – It’s fairly accurate, too.
Oooh, you’re salivating now. What the device is doing in the above pic is tracing a circle with the XY scanning stage, and blinking on and off the three colored beams as it steps through various index positions on the route. By shooting a red and green beam, you get yellow. By shooting a red and violet, you get magenta. All three gives you the whitish beams you see just to the left of the 6 o’clock position. Repeat this over and over at a fast speed and you get an outwardly radiating fan of beams. Vary the start position of the on/off blink sequence but keep the XY positioning sequence the same, and you can make the fan rotate left and right in the classic laser tunnel fashion.
We’ll investigate the position sequencing later when we get into the guts of the box.
You can find many videos of this and other devices in action online, but the one we like best is from Amonstar, a seller of a rebranded CASA device. The demo vid shows some killer color-changing fans around 0:25 and an overall fairly good demo of the unit. A few too many spinny circles, and you miss out on the neato random-shooting space invaders mode, but still good. Check out Amonstar’s page and video here.
It looks like they either found a song that the device had extreme sensitivity to, or built themselves a DMX routine to actuate it very close to in time with the music. The track in question is “How Old R U”, by Master Blaster. Sampling an old Italian disco song about reminiscing where an old flame may be these days, Master Blaster’s version succeeds in sounding both campy and somewhat skeevy at the same time. Classic! But the gravelly bass warble interleaved with a big fat kick drum makes for a fine piece of dance club history. Watch the totally 90′s music video: Youtube – Master Blaster – How Old R U.
Here’s the dirt on the device:
CASA CTL-BM Specifications:
- Total Output Power: 270mW
- RED: 100mW, 650nm diode laser
- GREEN: 70mW, 532nm DPSS laser
- VIOLET: 100mW, 405nm (Blu-Ray) diode laser
- DMX, Auto, Sound-Activated Operation modes (Latched on startup)
- 100 patterns, 500 laser effects
- 9 Channel DMX Control (Yes, it works with Freestyler)
And without further ado, let’s go ahead and crack this thing open!
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