Have a few starter questions here...

Questions, Suggestions, Tips, Etc

Have a few starter questions here...

Postby redskyrc » Fri Aug 05, 2011 3:45 pm

Hi, I am interested in building a 2.x laser. I am a radio control airplane hobbyist. I have been reading and downloading instructions and reading some more... I am most intimidated by the electrical part. Can someone show me some build logs with pictures or videos on how to hook up the electrical portion of the laser? I just want to make sure I willl be doing it correctly and safely. I have also been reading about voltmeters and checking on how to check continuity. Can someone send me some links to some electrical builds of the electronics bed? also how to wire it properly?
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Re: Have a few starter questions here...

Postby TLHarrell » Fri Aug 05, 2011 5:57 pm

Have you considered a turnkey solution? I have a Full Spectrum Engineering 40w hobby laser and it works great. Kind of small work area though. I will be building a much larger machine as soon as I can monetize the smaller one. It's a decent starter unit though.

If you go the DIY route, there's plenty of people here on the boards who will be happy to help out and point you in the right direction. Majority of the wiring is basically connecting components of the system together. Essentially, it is similar to putting together a home stereo system. It's not all that complex once you break it down piece by piece.
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Re: Have a few starter questions here...

Postby redskyrc » Mon Aug 08, 2011 2:42 pm

I appreciate the input. I am going to read a lot more and decide whether I am really going to go into this project. I really don't care if it takes me months, as long as I do it correctly and safely. I have posted this question under the electronics category, but maybe someone here can answer. How do I make sure the frame and skins are grounded properly? The instructions call for this and I want to make sure I will be doing it right. I also read somewhere that when you unplug the unit, you have to wait some time before working on it. How can I test to see if it is safe again to work on after unplugging the unit? Is there a certain amount of time to wait? I imagine it takes at least a few minutes given the voltage we are working with correct? I just don't want to guess at anything. another question I have is about checking continuity. Is there a website someone can point me to? I have been doing a bit of reading about this and basically you are checking if the circuit has little resistance.

I understand how you should only assemble things with one hand so that if electricity were running through that hand it would only go through your fingers rather than you heart and kill you. am I on the right track here? I also read that you should use a grounding band. I suppose this keeps you grounded and less change of an electrical shock so the electricity goes to the grounded object rather than through you.

The instructions also state that you need to know how a voltage divider works. Can someone explain or point me to a good link I can read about this?
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Re: Have a few starter questions here...

Postby lovebugjunkie » Mon Aug 08, 2011 4:36 pm

Not sure about all aluminum extrusion but the stuff I pickup on from 8020 inc, has some type of clear coat on it. I had to do some light sanding to get a good ground connection on another project I did using it.

May be over kill but next frame build I will drill holes on the extrusion at each junction and bolt down small length of grounding wire to each piece and with a longer one going from frame to common ground of all components.

I think the “one hand method” has more to do with you don"t want to be touching a “energized” point and then grab something else that would give a better ground that what the equipment uses that you are working on. Something along that line.

I have learned two things from my experience with power. 110 tingles, and 220 down right hurts if you are still around to learn from getting that experience. Have no plans on finding out what anything higher then 220 feels like.
Last edited by lovebugjunkie on Mon Aug 08, 2011 11:53 pm, edited 1 time in total.
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Re: Have a few starter questions here...

Postby TLHarrell » Mon Aug 08, 2011 6:06 pm

In High School, a buddy and I built a HeNe laser power supply from a kit. We didn't have it mounted in any enclosure yet while we were testing it out. His little brother decides to go all "Jedi Knight" with the tube on us and my buddy ended up with the power board sitting flat in his hand. Now, this thing was a bank of capacitors the size of a small paving brick, and it was energized. I dove across the room to unplug it as all he could manage were some odd contortions and surprised squeaks passed through a clenched jaw. Took about 2 months for the image of the circuit board traces to fade from the palm of his hand. Fortunately, he was merely stunned from the incident. His younger brother eventually suffered more than my buddy did.

Grounding should not be a major issue. The extrusions all are anodized, but where they are cut, drilled, milled, sanded or screwed they will create a connection. Test this by setting your DVM (Digital Volt Meter) to Ohms (x1) and probing along the frame and to the ground prong on your power cord. The needle should swing practically to 0 at any point where you make actual electrical contact. Test out all grounding connections for the electronics components, any additional ground wires, all bolt connections, etc. The outside anodized part of the frames you will likely not get a connection.

For the electronics, take each piece at a time. All the controls are low voltage stuff. You simply mount the power supply for the low voltage, then run wiring to power each module. Then you run the control wiring (to the motors, between boards, etc.) per the specifications and documents. The high voltage stuff you would basically do last. Even then, it's a matter of properly mounting the components, wiring it per the documentation, making sure everything is set right, then testing. Taken as a whole, the project looks like a lot of work and a lot of complicated stuff, but if you break it down it's not all that difficult if you can follow directions and diagrams. Most stuff here is very well documented, and if you run into anything you do not know you can ask it here.
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Re: Have a few starter questions here...

Postby redskyrc » Tue Aug 09, 2011 3:26 pm

thank you for the info. I am looking at the plans D30011 and the instructions call for you to "solder wires to the power entry module"...it is under "Wire the Primary power". What kind of wire is needed for this? Is this the same wire that is shown on the "22awg Stranded 4 conductor Cable (Belden 8444). Perfect for extending the wires on NEMA 17 & 34 stepper motors." kits? Or is it another type of wire. the plans don't really show what kind of wire to use.

In general, for the 2.x electrical assembly, what kind of wire am I supposed to use?

Thank you in advance.
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Re: Have a few starter questions here...

Postby TLHarrell » Tue Aug 09, 2011 4:18 pm

I haven't reviewed the entire set of plans myself yet, but wiring would be one of three types and gauges:

:arrow: Low Power/Data/Control:
22 ga light duty stranded type wires for operating stepper motors and connecting data lines between modules.

:arrow: 110V Power:
This would be more like 14 ga or 16ga solid core copper wire. This would be where you run power from the power cord (power entry module) to the 110v inputs on the power supplies. 22 ga will not work for this.

:!: High Power:
This would be the wire leading from the laser power supply to the laser tube. It is very high voltage and is silicone covered wire.


As per good electronic operation and theory, do not run any of these types of wires parallel to others. Keep them segregated or they can induce currents in the other wires, causing all kinds of invisible, hard to trace electrical interference. This is why people usually have the laser power supply on a (grounded) metal shelf, shielding the low power data connections from the high voltage section. Usually, you would plan the layout of your individual modules so the power supply terminals are on one side of your board, and your data lines are on the opposite side.
40w Full Spectrum Engineering 5th Gen Hobby 20"x12" w/ Rotary Engraver
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
408-47-LASER - Skype: whitelightlaser-thomas - Facebook: White Light Laser
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