Wednesday, December 22, 2010

Gutting a dead scanner

This broken HP C7670A scanner should come in handy in this project! I'm sure I'll find the one stepper I've been looking for, and maybe I'll use this one as a base for the whole laser CNC thingy.

The broken HP C7670A.

So I opened it and removed the PCBs. They're going back to the electronic waste disposal...

I like the way they tighten the belt in this scanner!

This spring keeps the belt tight while travelling around with it.

Remove the poisonous light bulb carefully... It's VERY fragile, like an uncooked spaghetti, and contains poisonous mercury. Mercury causes all kinds of nasty stuff and it can even make you homosexual! You heard right! Well at least if you're a bird, according to BBC.

Be VERY careful with this lamp...

I took the optics away from the scanner tray. Pretty. Dunno what to do with them yet.

Some mirrors, a lens and the image sensor.

Tray's now empty. I wonder how I will do the second axis...

This might be a CNC base one day.

Here's the stepper motor.

SLC-42D003 stepper motor.

The motor model is SLC-42D003. The manufacturer has printed some specs on it. How kind of them!
It reads: 1.8 deg/step 11 ohms.
I couldn't find any other info on the net.

I was wondering about the motor's voltage. I checked the power supply PCB again.

I love these helpful stickers. More of them, please!
I wasn't hoping for anything like this. The manufacturers had placed some convenient stickers to help me!

So, the power supply of the unit provides 5V, 12V and 24V. 5V must be for the logic. I googled around and found that the scanner lamps are using 12V. 24V is probably then the power supply for the motor. That should be convenient, since that's also the nominal voltage of the printer stepper I've already salvaged. I might be fine with just one motor power supply.

That was today's adventure. Now to sleep!

Tuesday, December 21, 2010

Gutting printers for steppers

Immediately after I started drooling at the DIY CNC videos on the 'net, I found two printers in the garbage. What luck! There's the free stepper motors I was hoping for! Or so I thought.

The models were HP Deskjet 5150 and Deskjet 656C.

HP Deskjet 656C straight outta garbage.

After all the trouble of carrying them home, I noticed they both had plastic optical guides next to the printhead pulley system. At first I was thinking "why do they need optics to guide steppers?" Then I understood the grave situation. There were no steppers. It seems that HP has found a cheaper way to get their precise printhead movement. They use DC motors with optical linear encoders to give feedback on the printhead's position.

HP's optical guide for the printhead.

I decided anyway I would gut the both printers for parts. I would probably be needing them for the mechanical construction.

You need a torx screwdriver set to open these things. Every screw on these seems to be a torx. I needed at least the T10, T15 and T20 to open the printers.

My trusty screwdriver set.

At this point I want to make it clear that opening printers is MESSY! Be prepared to get ink everywhere.

A partially gutted HP Deskjet 5150.

I found another optical guide on the Deskjet 5150. It's a rotary encoder that gives the printer feedback on the paper feed DC motor's position. Again they have saved on steppers.

An optical rotary encoder.
And then I found my first stepper! On the Deskjet 656C they still use a proper stepper for the paper feed motor. I need one more for the build.

The first stepper motor I found!

I took out the stepper and googled it's model PML55L-048-HPG9. The first search result gave it's data:
Nominal voltage: 24V, Steps / revolution: 48, Step size: 7.5 degrees. Everything I need to drive it, I quess! I've never used stepper motors in my projects before...

This one will come in handy.

Even without google it's easy to distinguish a stepper motor from a DC motor. Stepper motors have 3-6 wires on them while DC motors have only 2. For more info on the various motor types, here's a great tutorial page: Jones on Stepping Motor Types.

So here's the conclusion: if you're looking for steppers: Deskjet 5150's got zero, 656C has one.

But the Deskjet 5150 sported something else I'm sure I'll find useful: a screw-mountable metal rod that the laser head can travel on.

I'm planning to use this rod in the CNC build since it's got some convenient screw holes.

OK, that's it for today! At least some progress.

Monday, December 20, 2010

Gutting a DVD burner for it's laser

There are a ton of instructions on the net about ripping laser diodes out of old 16x DVD burners. Well, here's mine.

Quite soon after starting this project, I found exactly what I needed: a 16X DVD burner from an old computer in the electric waste. Here's the poor thing before the operation. It's an LG GCC-4480B CD-RW/DVD ROM drive.

The unsuspecting DVD burner before meeting it's fate.

And here are the tools I need. Let's get to work.

With these I was able to get everything out.

Warranty's void now.
Pull or cut the cabling to get the PCB out of the way.
View from top. Laser lens is visible.
View from bottom. Take out the screws connecting the rails of the laser module.

Inside the top cover I found this cool little ring-shaped magnet. It's quite powerful for it's size, maybe a Neodymium magnet. It found a new home on my fridge.

The magnet.
And finally, here's the beef. The laser module with it's laser diodes.

The laser module. A lens is seen on the top, while the laser diodes are hidden in the sides.

When trying to open the module, bad luck struck.

This is what you get when you save on your screwdrivers.
Side view of the laser module. The red 650nm laser is there!

The red laser I'm looking for is in the picture above. You can see three leads coming out of a orange PCB, two of which are soldered together. That is the negative terminal.

And here is the infrared CD laser diode. I managed to wreck this one.
In the above picture, the IR laser diode is hiding beneath the little green PCB on the side of the module.

The laser module has two laser diodes (LD). One is for reading CDs and one for DVDs AFAIK. The CD laser is infrared and invisible and the DVD laser is red at 650nm. I'm looking for the DVD one. The infrared one is more dangerous since you can't see the beam, and still it can blind you.

Getting the laser diodes out of the module proved out to be the hardest part. The CD laser diode wouldn't come out and got broken. Luckily, I got the 650nm laser diode out mostly unharmed! I hope it works!

Finally, there it is!
Next it's time to build a driver circuit to try this one out!

Here's some other nice pages about the DVD lasers:
Planetstephanie - DVD laser
Instructables - Laser Flashlight Hack
Showyoushowhow - DIY DVD burner laser pointer the right way
Sam's Laser FAQ - HUGE amount of info on laser diodes

Parts list

Here's a list of the parts I'm planning to use.

2 stepper motors for XY control (0€, from old printers / scanners)

Mechanical structure for the XY table (0€, I'm planning to use printer & scanner parts)

Red laser diode 150mW - 250mW 650nm (0€, from an old 16X DVD burner)

Laser module with focusable lens ($9.50 from AiXiz)
This is needed to collimate the laser beam. I don't know what that means either, I just read it off some other tutorial page! I ordered the 650nm 5.0mW 12x30mm module with a glass lens as an accessory. Normally they come with plastic lenses. Sounds bad having a plastic lens on an engraving machine that's supposed to burn stuff.

Laser diode driver circuit (?€, parts list later)

Arduino (20€ from your nearest Arduino dealer)
To control the stepper motors. I will use Arduino for this project because of the ease of use and available libraries. I have one already.

Adafruit motor shield for Arduino (?€ from nearest Adafruit dealer)
This one is needed to power the motors. Arduino itself cannot power the motors, the motors need another power supply and some driving circuitry. I want to get engraving as fast as possible so I don't want to waste time making my own PCBs. This kit seems perfect for me.

Computer to send control data to Arduino.

Control program on the computer that eventually controls the whole thing
I'll code it when the hardware is ready.

Cables, screws, tools, power supplies, whatever.

This list will be updated later when things clear up.

The goal (video)

Here's a video of what I want to accomplish. The CNC should also be able to cut through some thin plastic. I want to be able to engrave items (leather / plastic / wood / etc) and create some stencils with it eventually. I'm planning to make the device much smaller than the one in this video, though.

For dummies: It's a Do-It-Yourself (DIY) Computer Numerical Controlled (CNC) Laser Engraving Machine.

First post


This blog is about a Do-It-Yourself CNC Laser engraver project I'm currently working on. Later on I might write also about some other things.

I'm a Finnish hacker, 26 years old at the time of this writing. For those who got scared: with hacker I don't mean an internet criminal. It just means I like to repurpose electronic devices or use their parts to make something else. You can just say 'nerd' if you will.

My plan is to build a laser engraving machine that is made mostly from recycled parts and to document it in case someone else is interested.

I'm planning to make the blog a bit like a manual / tutorial, so old posts will probably get edited along the way as I get more knowledge & have more time to write.

Currently I have no idea how often I will get to update this blog and when the thing is going to be ready. But like they say: live for the journey, not the destination... No, I'm just kidding. Fucking hippies.

One thing that makes the project very interesting for me is that I have no previous experience with lasers, or any mechanical builds. I have worked with electronics for years now and I'm fairly good at programming, but I'm sceptical expecially on how good mechanical build I will be able to pull off.

What sets this CNC build apart from the many others you can find from Google is that I don't have access to any wood/metalworks equipment. I have this crazy plan to build the whole thing out of garbage. Time will tell if I succeed in it, or if I eventually decide to get some custom parts.

So, this is what this blog is about. Stay tuned. Meanwhile I'll go bust open some electronic garbage.