Instructables

Step 5: Electronics

I started soldering the steppers. I used a ribbon cable to connect the steppers and solder them to the existing connections from the DVD boards. On the other end I solder a four pin header so that it could be used with a breadboard. The same thing goes for the Easydriver, solder pin headers and use them with the breadboard. Ribbon cable can be found in abundance around old computer shops and service centers. All those old disk drive cables can be of good use.

In the schematics I have added a relay for use with a fan. This can come in handy as the engraving produces some smoke.

The Easydriver have two pins called MS1 and MS2, these sets the step sequence. Tie them both to the five volt output from the Easydriver. This sets the step sequence to micro stepping . The four pins from the stepper connect to the motor output. All steppers I have found have all had the same pinout on the small connecting PCB. Connect the pins in the same order to the Easydriver as on the connecting PCB. The control pins (step, dir, gnd) goes to the Arduino. Besides this the Easydriver needs motor power connected. I use a twelve volt wall wart that drives the motors, fan and Arduino. There is a potentiometer that controls the power to the motors, I just set this to the lowest setting and turn it up a tad if the steppers don't have enough force. I don't know the rating on the steppers, if they gets to hot you’re driving them to hard.

The fan just needs to be connected to the fan output. A small computer fan works well, just connect the positive and negative leads to the correct output.

The laser driver is an LM317 based circuit with no specials. This will work fine but it is far from optimal. I am driving the laser diode far too hard at about 300mA and if you do that you can’t expect a very long life for the diode. The best solution would be to find a stronger laser and better driver but to keep to the spirit of things I wanted to use the laser from the DVDR itself. Laser on/off is controlled by the same relay as the fan.

If you want to simplify you could skip the whole laser driver and use a readymade driver. Then all you would have to do would be to connect the power to the fan relay. Of course this would probably be a little bit more expensive.

The whole thing evolved into a new Arduino shield, the Laser Shield. I have included the schematic and board layout in Eagle format . Creating a circuit board is a bit out of the scope for this instructable, but there are lots of really good guides here on Instructables.
If you want to make your own layout with Easydrivers I have made a Eagle library with the driver, it can be downloaded here .

 
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Which pin in Arduino is used to control the laser?

erniehatt1 year ago
What size Laser would it take to cut 3mm acrylic
ianmcmill1 year ago
(removed by author or community request)
Just wanted to say
Great tutorial and awesome idea !
jtabor22 years ago
Great work, Groover. Could you recommend a ready-made driver?
Ryutso3 years ago
So I came into possession of a groove2 laser diode driver. Would that work in place of your LM317 circuit?
It is a bit unclear how and where I can put my own driver.I will use a 1w laser diode,of course with protection,haha.Can you help me out on that?I will use this driver : http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=260599140613&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
GridPole3 years ago
Thanks for posting this Groover. I had a bunch of old PC parts, including a few DVDRs that I was going to toss but after seeing this it was quite an inspirational project.
Do you have to solder the wires to the stepper using the PCB strip? Can't you just solder them directly onto the pins on the motor? Asking because this may be a little beyond my skill level.
Groover (author)  GridPole3 years ago
You could solder direct to the motor pins. I know a couple of people who did just that. I have no particular reason for soldering to the PCB strips.
can anyone tell me if this will work to drive the laser and turn it on/off with Groover's design. I'm not too good at this stuff and i would like to buy a ready made driver.

http://cgi.ebay.com/Constant-current-laser-diode-driver-80-500mA-w-TTL-/380348154175?pt=LH_DefaultDomain_0&hash=item588e84413f#ht_754wt_1141
I was able to hook my motors up but I am having a problem. One of the axis is only turning in one direction. I try to give it commands to go the other direction but it doesn't work. I even tested my other motor that works both ways on the other motor controller and it still only moves in one direction. Any ideas?
Never mind it was a bad solder joint...
ellensundh3 years ago
I have a question... I have a vr05r051 relay but I can't find any information anywhere on how to use it..

Thanks!
Groover (author)  ellensundh3 years ago

Try this link.
lperkins3 years ago
Any tips on how to figure out the pinout on one of these motors? I wired it up straight across as suggested. My X axis will move forward 10mm every time I issue X10, but if I issue X-10 it moves the same way, just only half as far. My Y axis gets stiff and the motor buzzes if I turn up the power, but it doesn't even twitch when told to move. Instructions for determining if a servo is bad would be appreciated. :)
Groover (author) 3 years ago
LM317 have three connection points. I cant check the Eagle files as I am at work at the moment. But if you look at the schematics you see the input connected to the relay out and the input connected to R1, to adjust the power to the laser the ADJ pin is connected to R4 and R5.

I'll have to give you a better answer as soon as I get home and can have a look at the board layout.

Pfeonyx Groover3 years ago
Thanks for the info on this. I was misreading the eagle files. I originally confused the LM317 for the interlock. I deleted that message to avoid additional confusion. Sorry for the confusion.
Pfeonyx Pfeonyx3 years ago
@Groover - What is the interlock on the Eagle board file next to the VR05R051? Also, what is the 2 pin connector next to the heatsinked LM317? Thanks again for this instructable!
Groover (author)  Pfeonyx3 years ago
The connector next to the LM317 is a alternative connection for the laser. It is just connected in parallel to the screw terminal. If you buy a ready made laser sometimes they comes with a connector that can be used there instead of the screw terminals.

The interlock is supposed to be a safety feature. You can put a jumper there and ignore it or use it as a safety switch. I think a hardware switch is a safer option that to just trust software. For example if the software would malfunction for some reason while the laser is on it could be a good idea to be able to shut it down without having to pull out the power and USB. Of course this was never implemented in my hardware design even if it would be a good idea.
mplaser3 years ago
Great Instructable! I'm interested in making one of these at my dorm and would love to start asap. Only problem is I'm a Mec major at my school not electrical :(. I'm not too familiar with the schematic and some of the components used. Is there anyway you could list the electrical components or explain it in layman terms? Sorry for any inconvenience, bit I'd love to start building one!!