Galvo
From Eric
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=Galvo= | =Galvo= | ||
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| + | A "laser scanning galvanometer" (or "galvo" for short), is a piece of hardware to display patterns, texts, etc. on walls using a laser beam. | ||
== Objectives == | == Objectives == | ||
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There are also two short videos [https://www.youtube.com/watch?v=E4JKMRbQh9g here] and [https://www.youtube.com/watch?v=yHWOThJy13o there] . | There are also two short videos [https://www.youtube.com/watch?v=E4JKMRbQh9g here] and [https://www.youtube.com/watch?v=yHWOThJy13o there] . | ||
| - | Needless to say, these | + | Needless to say, these attempts were unsuccessful. |
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| + | The first solution was much too non linear (and slow, but at that time, my idea was simply to point a laser beam to some moving object, so the reaction time was not that of a problem...). The second solution was pretty nice, but the position control was a bit weak. In any case, the speed would have been much smaller that can be achieved using an industrial product (even a very cheap one). | ||
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| + | So I ended up buying a readymade mage galvo from China (simlilar to [https://www.ebay.com/itm/20KPPS-30KPPS-Galvo-Scanner-ILDA-Closed-Loop-For-Light-Show-Stage-Lighting-Laser/123898561176?epid=9031429821&hash=item1cd8ee0298:g:YnYAAOSwtbhcreDI this one], seach for "laser scanning galvanometer"). | ||
The galvo comes with a +15/-15v power suply and two drivers (one for each mirror). | The galvo comes with a +15/-15v power suply and two drivers (one for each mirror). | ||
Latest revision as of 14:46, 7 March 2021
Contents |
Galvo
A "laser scanning galvanometer" (or "galvo" for short), is a piece of hardware to display patterns, texts, etc. on walls using a laser beam.
Objectives
As a followup to my previous efforts to control a CRT, I have resurrected a setup that I did quite a long time ago to control a laser beam. I have done several attempts, using a handmade galvo and a moving mirror.
Here are picture of the two setups:
There are also two short videos here and there .
Needless to say, these attempts were unsuccessful.
The first solution was much too non linear (and slow, but at that time, my idea was simply to point a laser beam to some moving object, so the reaction time was not that of a problem...). The second solution was pretty nice, but the position control was a bit weak. In any case, the speed would have been much smaller that can be achieved using an industrial product (even a very cheap one).
So I ended up buying a readymade mage galvo from China (simlilar to this one, seach for "laser scanning galvanometer"). The galvo comes with a +15/-15v power suply and two drivers (one for each mirror).
The only things that remain to be done are
- to generate the ILDA signals to drive the mirrors (via the drivers) from two 0-5v signals generated by an Arduino micro and a couple of DACs (this is explained below).
- to write the piece of software to the generate patterns to display.
Schematics
The schematics is basically the one proposed at [1].
Please note that the 5V used for the microcontroller / DACs is obtained from the 15V power supply. I am not sure that a genuine 7805 will appreciate the 10V shift... So I'll use some of the nice 3-pin step-down replacements such as:
Breadboard
The initial setup has been done on a breadbord. As usual, this is a real mess.
PCB
