Modifying a "Cheap Chinese" Red-Green starfield laser to allow for motor control

[tfischer]

Now put the unit back together, and test it. First try it without the 1/8" cord plugged in. It should operate just like the laser did before your mod. Hopefully you didn't break anything like I did.

If the worst happens, and something doesn't work, do the following:
- Make sure the controls are set correctly. E.g. not in "sound sensitive" mode, motor speed turned up, etc.
- Open it back up, POWER CORD UNPLUGGED, and make sure all the little molex plugs are securely plugged in. I think I forgot to mention to plug the motor cord back in but hopefully you figured that out
- Look for any wires that got broken or damaged.

Here's the final results. Looks fairly professional:

[tfischer]

Assuming all is well with nothing plugged in, try plugging in your cord. Make sure the two bare wires aren't touching, and the motor should stop. Now touch the two wires together, and the motor should spin. Unplug the cord again, and the motor should spin.

If all works, congrats! You've successfully modded your laser!

Now... how to use this thing:
What I intended to do was put the laser power on one controller channel, so the whole unit could be powered on/off.
Then, using a second controller channel and a relay, I could toggle the motor spin on/off independently of the whole unit.

Connecting the unit to a relay:
This is a bit beyond the scope of this article, but I'll give you some hints. If you're using a standard 120V lighting controller you'll need a 120V coil relay, and perhaps a C7 or a resistor to use as a "snubber". If you connect this to a DC controller, you'd need whatever coil voltage your DC controller is using.

You'll want either a SPDT or a DPDT relay, which gives you some flexibility (if you use a DPDT, you'll only be using one of the poles, essentially using it as a SPDT). Depending on how you wire it up, the motor will either be off until the relay is energized (normally open), and then start spinning, or the motor will be on until the relay is energized (normally closed) and then stop.


Hope this helps someone. My little laser gave it's life to bring you this write-up But again if I hadn't killed the green laser due to my carelessness the mod would have been 100% successful, and I'd definitely do it again on a new unit (still debating whether I'll actually buy a replacement).

[Skunberg]

Great write up Tim! Good pics with markup, detailed step by step.
Were you planing to use it inside or outside?

Brian

[tfischer]

Great write up Tim! Good pics with markup, detailed step by step.
Were you planing to use it inside or outside?

Brian

Was going to use it on the garage door (which is a dark brown and doesn't take floods well). Unfortunately, I didn't try it out there before wrecking it, so I'm not sure how well it would have worked I did test it around the house and in the back yard... I'll probably try it up front with just the red (the dimmer of the two colors) and if that looks good I may replace it.

[AverageJoeTX]

Excellent write-up thanks for taking the time to share. I purchased 4 of these on amazon for $23 each. I plan on encasing them in plexiglass and putting them on a pole, about 10' high (to keep people from looking into it) in the center of my front yard, one facing in each direction to catch all the trees and rooftops. This mod would solve the problem of accessing the units to change from solid to flashy.
Just another thing to add to my to-do list, but it should save me a lot of heartache later.

[Skunberg]

I know these look pretty good at 5ft, 10ft 15ft. But I wonder when you back off to 30ft or so how large a area does it grow out to. And do those sharp dots turn into large fuzzy circles?

Brian

[RPM]

I had found these from a seller on Ebay and I was thinking of getting a couple and modding them for DMX control.
Maybe in my spare time

OK so most of you here are so far above me when it comes to hardware mods that this thread will probably come off as laughably simple. But I wrote it up for another site and figured I'd post it here to just in case someone found it interesting, informative, or just wanted to laugh at my documented screw-up ;)

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A month or two ago I ordered one of these cheap lasers from Meritline for only $33:

http://www.meritline.com/mini-laser-...--p-60905.aspx

[dmoore]

I know these look pretty good at 5ft, 10ft 15ft. But I wonder when you back off to 30ft or so how large a area does it grow out to. And do those sharp dots turn into large fuzzy circles?

30ft back would cover a good 50-60ft area. Maybe this helps:

[tfischer]

David - one thing I was wondering about these - when you aim them up at trees, etc. do you have to worry about them bothering aircraft? I'd hate to have the men in black show up at my display and haul me in

[RPM]

That was my thought too. I live within a mile of a small private airfield and about 9 miles from a commercial airport with a flight path directly over my house, so pointing it up would be a big no-no around here. Sure looks cool though

David - one thing I was wondering about these - when you aim them up at trees, etc. do you have to worry about them bothering aircraft? I'd hate to have the men in black show up at my display and haul me in