First RGY Spirograph

[Sigi424]

Hi, I am new to lasers and I would like to build my first RGY spirograph. Over the past week I read a lot of articles about lasers and I think that I am ready.

This picture shows how I would like it to look:



I will start with the lasers.

The lasers that I chose are 5mW green module DealExtreme: $15.95 Geniune New Wish 5mW Green Laser Module (5V) and 20mW red module DealExtreme: $7.89 20mW 650nm Red Laser Module (3~4.5V 12mm) I know that the green one has a driver already, so that means that I can you just plug it on a 5V source, but the red module seems to be without a driver. That means that I need to buy one separately right? I looked at the lava driver but I don’t think that I need a driver for over $20 when I have a module for $7.89. Is there any other cheaper driver that I can use? Also the description of the red laser says that it needs 3~4.5V. How do I get how many mA does it need?

The second things are the mirrors and filters.

I found this dichroic mirror (reflects green ,passes red) to be the cheapest I could find DIY Laser Show , but I still think that its quite expensive. Do you know any other shop where I can get it for a cheaper price? I also found out that edmundoptics are one of the best on the market. So I found this dichro( reflects red, passes green) 45° Reflective Dichroic Color Filters - Edmund Optics and I wonder, is there really a difference between these dichros except the brand? I would also like to know if it matters if the mirror reflects red and passes green or reflects green and passes red? Which one is better? Also I read that the front surface mirrors are the best (Q: What’s the difference between rear and front mirror? Why is front better?) so I chose these Optotronics Product Details . I hope they will work fine, but if you have any other cheaper and better solution please tell me.

The last think is the IR filter, which if I understand is a filter that blocks the harmful IR waves from green lasers. I want to have my laser experiments save so I found these IR filters Optotronics Product Details and Commercial Quality Heat Absorbing Glass - Edmund Optics . When I looked at the description it said that it absorbs 80% 800-1000nm wavelengths (1st one) and the other 60% from1700 to 2500nm(2nd one) . :huh:This is a huge difference, which one is better? Which wavelength are more harmful? The prices are also totally opposite the one from Edmund costs 24.50 for 102x127mm and the other one $0.99 for 25mm square.

Oh I almost forgot: Are these modules reliable and do I need to heat sink them if I would use them let’s say 2 hours in a row?
That’s all Please help me. Thank you very much :thanks:

 

[MarioMaster]

You'll want the first IR filter. The wavelengths you want to block are 808nm and 1064nm, as these are the ones generated by the DPSS process inside green lasers.

Also, I would not worry about the IR leakage from a 5mW module - it's likely to be insignificant.

The 20mW red module you linked from DX will have an internal driver like the 5mW modules. You just need to supply it 3-5v and it will work.

For choosing dichros, you need to make sure they pass/reflect the wavelengths you want (532nm and 650nm in this case) and also factor in the power losses from passing/reflecting light off it. It may be hard to choose as you can't always find the exact data you need.

I hope this clears things up a bit for you

 

[DTMF]

i have made a spiro just like in your diagram . a 3 motor spiro is cool BUT a 4 motor is even better . i junk'd the 3 motor set up and went for 4 i tried 5 and 6 motor's but 4 was over all the best combo . spiro's are realy cool once you finish it and get to play with it . hour's of fun fun fun . here's a pic of my mockup and a few vid's of it done to show how it can look finish'd . if you have any question's on the wiring and layout pm me

now some vids :

YouTube - blu+green=?

YouTube - green spiro 2

YouTube - blu-ray spiro

 

[Sigi424]

Thanks for responding :thanks:
But I have still few questions.

You'll want the first IR filter. The wavelengths you want to block are 808nm and 1064nm, as these are the ones generated by the DPSS process inside green lasers.

What' is the other filter for then? Also does it mean that the red lasers don't have any IR? So it might be said that they are safer than green right?


I would like to also know if it matters if the mirror reflects red and passes green or reflects green and passes red?

The last question is: Are these modules reliable and do I need to heat sink them if I would use them let’s say 2 hours in a row?

Thank You!:thanks:

 

[MarioMaster]

The second IR filter you showed is for blocking longer wavelengths, in the deep IR field - maybe not useful for DPSS filtering but for other scientific applications.

It doesn't matter how the dichro reflects or passes, so long as it passes one and reflects the other.

You are correct - the red laser will not emit any IR, it is not DPSS and only emits red light.

I would recommend getting heatsinks for both lasers, especially the green for extended run times - the modules should be fine running continuously if they are properly cooled.

 

[HIMNL9]

Uhm, as far as the green module is not very high power, the amount of IR is relatively low, and usually also not right focused ..... if you want to block part of it and don't find an IR filter, use a diaphragm at a certain distance from the module, like in this pic

Then, about the dichro, the cheapest one for pass green / reflect red is the 90 degrees mirror that you can find in any PHR sled ..... not a 98% transfer professional one, but still transfer 90% or few more green and reflect at least 95 % of the red, so, if you want, you can arrange it in this way (just remember to use the front face for reflect the red, and pass the green through the rear face, otherwise it "double" the red dot and is less efficent)

the mirrors are just for give a longer path to the green if you want to use the diaphragm for take away the IR (in brown in the pics), if instead you don't care about it, just put the green module straight passing the beam through the dichro (that is the violet mirror in the pic, sorry i not labeled it) ..... just an example

 

[Sigi424]

Thanks to everybody!
:thanks:

Then, about the dichro, the cheapest one for pass green / reflect red is the 90 degrees mirror that you can find in any PHR sled

I found this Empty PHR-803T Sled With Optics and Turning mirror [EMPTY PHR-803T] - $0.40 : Dark Lasers, The one-stop shop for all your DIY laser needs! Does this sled have the dichroic mirror that I need?

What's diaphragm? I know what it is in humans but not in the laser world

Also from the pictures (btw nice drawings! What program did you use?) I understand that the IR enlarge with the distance because it's focused to infinity, so if I have a laser that is focused at a short distance it's exactly opposite right? Short distance - large IR, far distance - smaller IR but larger dot? But I didn't get one thing, why do some laser have IR filters if you are telling me that I need some distance between the module and the diaphragm to catch the IR?

The last thing: What is the difference between 45 degrees and 90 degrees dichroic mirrors?

Thank You!:thanks:

 

[HIMNL9]

LOL, please don't make confusion (cause i already make enough of it with my bad english )

Ok, about the sled, all the PHR sleds uses a bandpass dichro (never understood why they used it, instead a normal FSM, but it's a luck for us ) as 90 degrees mirror ..... 90 degrees means only that is the mirror that turn the beam of 90 degrees, from horizontal (the diodes plane) to vertical (to the disk) ..... is this one, you can see it with different colors when the angle of observation changes

as you can see, the mirror have one side grinded at 45 degrees, that was done only for fit it inside the sled ..... anyway, the face that you can use is the front one, that is the one on the larger surface, for reflect red (and BR, if you need) ..... and "shooting" a green beam from the back (through the smaller face) it pass almost all the light through it, so you can use it for combine red (or BR) with green, in this way

Using it in reverse cause some problems and duplicate reflections, this is the better system ..... also, it works also in different angles, til a certain point (i drawed it working with 2 beams coming at 90 degrees, but if for space reasons the modules must be positioned in different angles, it work the same)

A diaphragm is just an opaque plate, usually black for not cause reflections, with a hole ..... cause the IR is focused in different angles than green, it's usually more diverging, when the green is focused at infinite, so if you put on the beam path a plate with a hole of the diameter of the green beam, a good part of the IR, that is more diverging, is intercepted and blocked ..... anyway, as i've said, for low power modules, the IR part is not too much significative, and for high power ones, usually they already have IR filters.

Oh, yes, the program is just coreldraw

 

[Sigi424]

Ok.Thank you very much!:thanks: