How to monitor your reprap remotely with skype!

I was pretty pleased with myself when I thought of this. It is super simple, but it works well. I have been very nervous to run down to do the laundry, or to check the mail while I am printing. Not that my machine has problems, but I want to be there if it does. I looked into all kinds of different nanny-cams, and streaming webcam setups before I figured out the absolute simplest possible option.

1) Set up a new skype account on the machine by my printer.
2) In the privacy setting of the preferences, configure skype to only allow calls from people in your contacts

3) in the calls section, set it to auto answer calls and automatically start video when connected.


4) add yourself to the contact list
5) call yourself from your iphone!

Now, smarter people than I will pipe in here and say that having an always-on video conncetion on the internet is a setup for disaster. I only turn this on when I am running out of the room for a bit, and I turn it off when I return. The security settings ought to do a good job of not letting strangers peek in on your prints, but I don’t think I will run naked in front of the camera just to be safe.

Using a Bowden cable on the reprap prusa cold end


This post is to document something that I thought was fairly standard , but after talking to a few people I discovered it isn’t. Some people (I’m looking at you jkeegan) even thought it wasn’t possible. I have been using thin hdpe tubing for some time to enable my extruder to unspool filament by itself.

The benefit of the tubing is that it removes the effect that pulling has on the carriage positioning. The cable has a small washer between it and the extruder, and butts against a 3mm hole I drilled in the handle of my extension cord reel. That arrangement allows all of the pulling force of the extruder to be focused on spinning the reel as opposed to lifting the z axis off of the bed.

I used this setup most of the time I was working with the cupcake, and just set it up again for my gen 6 prusa.

Downsides: it does probably require more torque. You also need to be smart about using as little hdpe tubing as possible, as it seems like the friction scales non linearly. You also want the line to be as straight as possible between the spool and the extruder. My setup in the video is about as long as you want it to be. I could easily see using 10cm of tubing and simply setting the spool on the top of my prusa. That ought to have very little drag compared to the current rig. PTFE tubing might be worth looking into as well

I may end up building a bracket to allow mounting the reel on top. That seems like it would be a pretty manageable setup.

Just because I know someone will end up asking where I got that reel from: home depot is the answer, but you can also find it at amazon here

The hdpe tubing I believe is used for cold water lines such as ice makers. I picked it up at home depot as well.

Ways i have messed up reprap prints

This is a running list of all of the ways I have broken a print. This doesn’t have anything to do with my machine calibration. That’s a whole other post in itself!

-I got a snag in the filament feed which stopped extrusion.
-My heated bed shorted out on a bulldog clip.
-With the print not centered on bed it hit the endstop a few hours into the print.
-I have tried to print from stls not positioned at z-0.
-My cooling fan for extruder unplugged midway through and then the extruder jammed up.
-With the firmware z speed not limited properly, i have lost steps due to rapid z moves.
-Filament strips and stops extruding.
-I have run out of filament.
-On a multi part bed, one part became loose and then slowly caused blobs to build up on other parts. It eventually knocked most of the other parts loose.
-Before I had my heated bed fully figured out I had a LOT of parts curl and then come loose from the bed midway through a print.
-I didn’t check the scale of one stl I downloaded from thingiverse and it ended up being about 4mmx4mm.

Got any more to add? post them below in the comments! I’m sure I’ll keep discovering more.

Hardware store fix for prusa belt tensioner

On my self sourced prusa I have been going back and forth on how best to tension the belts lately. I had a zip tie hack that actually worked out fairly well, but it had a fair bit of slop in it, and I think that helped set up some vibrations and Generally keep it from being the best it can be.
I love my local hardware store. I went there (twice) today and on the first walk there I remembered this piece of hardware that is generally used to tension screen doors to keep them square. I checked one out and I think it will be perfect for my y belt. I may even throw one on my x axis, but I’m not sure if I need it.
Here’s a pic

As you can see in the pic I have been experimenting with a very light y stage. It is perforated hardboard that they sell for hanging tools. The actual bed will go on top of there with 4, 5mm bolts and have the glass and hbp clipped to it.

I have also gone with a double wide skate bearing for the idler end of the x and y axis. If the two ends are aligned, then you don’t need anything else keeping the belt “on” the pulleys. Simple tension holds them there. This has made things much smoother and simpler compared to using fender washers.

gen 6 and sprinter homing issue

I’m at the point of troubleshooting where I either give up and go for a bike ride, or seek help. So I’m seeking help, and then I will go for a bike ride!

I am having an issue where I can’t get the gen 6 board to properly home. I have tried to home it by sending gcode (G28 X0) through slic3r and through the slicer home buttons. It recognizes the x end stop when jogging and refuses me to push past the limit, but it will not home for me.

Here is a pic of my printer. On the x axis the endstop is on the far left side.

Here is my configuration.h file

To boil down my problem into one bite: if the x axis endstop is defined on the correct side, homing does nothing. If it is defined on the wrong side, homing does a few mm shutter and then resets to the original position.

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Go buy a Makerbot Grab bag!

I don’t remember who tweeted it, but I saw a tweet a week or so ago saying that the makerbot grab bags were a good deal. I looked at them and bought three. I figured that at $9 each they would be a good deal.
even if they had nothing but the ftdi cable.
I got my box today and Wow!

I got two of the grab bag #1 and one #2. Each of the #1′s had TWO ftdi cables, two early nozzles, 5 pfte barrels, 2 brass barrels, a bunch of thermistors, pulleys, a fan, and some plastic build plates. They said that the grab bag could or could not include those items, but I didn’t think it would come close to having them all!


The second grab bag was similarly stocked, with a ton of pulleys, belts, some rods, some wooden build platforms and a ton of fasteners and plastic bearings.

They said it in the description, but I want to reiterate it: If you are a cupcake operator, you should probably get this. It is a great source of spare parts that would have cost you hundreds to buy a few weeks ago from makerbot. It will hopefully keep your bot printing for a long time to come.

If you are not a cupcake operator: it’s still a damn good deal.

Thanks makerbot!

Reprap Prusa: pushing plastic, almost ready to roll!


Here’s an overview shot of the prusa, E-stop switch, and macbook. I still have to build the bed, but the rest is all there. Yesterday I flashed it with the sprinter firmware and I like it so far! The biggest thing is that it has acceleration. That enables lower torque motors to start slow and ramp up faster over time. I also installed pronterface, because replicatorg has been very buggy with my prusa. One quirk is that the default z-axis speed is set to 200mm/minute. That was way too fast for my 80oz/in motors. Perhaps with a slow acceleration curve they might get up to that. I cut it down to 100 and they were much happier.
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Prusa Update

It’s been a busy start to the summer! I was able to go to Maker Faire, and now that I’m back I’ve spent every spare second on my bike or at the new hackerspace in town. One benefit of being a hackerspace member is that I finally have a place to keep my big /noisy / messy projects!

Here’s a pic of where it stands right now. I have everything together, but it’s not wired up yet. I’m also replacing the clonedel parts as fast as I can. They are causing more trouble than they are worth right now.
Here’s a link to solid state depot’s wiki on my prusa.

Here’s a pic of my monster e-stop button. It came out of a printing press. It is wildly overkill, but it looks cool. It is currently wired up to the psu, so if the switch is tripped, it cuts power to the machine. dead stop.

I’ll update more when I do more. I’ve been learning how to use a lathe in order to drill out some hot ends. It’s been exciting so far…

Help me hack the Belkin Conserve

Howdy internets!

I love the idea of being able to safely switch ac power from a microcontroller. There are products like the powerSwitch tail from sparkfun that easily do this job, but I like to try to be as cheap as possible, so I’m trying to do it for half the price with the Belkin Conserve. This seems like it is just a relay built into a wall wart that is only activate for a pre-selected amount of time. Ideally it helps you reduce your energy use by only charging your phone for say, 3 hours, or by turning off your tv after you fall asleep.

I bought one thinking the relay was probably powered by a dc voltage, and then that I could activate it with a pin from the arduino. Maybe I would have to put in a mosfet or an opto isolator, but it wouldn’t be too hard. After opening it up, I realized that it was all AC and I’m at the limit of my knowledge. I don’t want to zap anyone or any thing, so I’m asking the internet as a whole: what can I do with this?

Here is a closeup of the front of the board,

Here is a closeup of the back of the board.

If anyone has any ideas on how to safely trip the relay from a microcontroller pin I would love to hear about it. If not, then maybe I’ll just let it do what it was intended to do. And then go buy the powerswitch tail.

DIY heated build platform for makerbot cupcake.

Let’s give this a try!
Tonight I prepped 4 3ohm 10 watt aluminum resistors with in two parallel pairs with solid copper wire. I gave it 12 volts of juice and it got plenty hot quickly, so hopefully this back of the matchbook effort will pay off.

I don’t have the aluminum plate with me, so I only prepped the electronics. This is what they look like.

And here is a closeup of one resistor.

I have been reading a few other blogs about other peoples diy hbp builds and I was getting really confused. Hydraraptor is using 9(!) 48ohm resistors on his reprap hbp. That seemed really high, considering the people doing it with nichrome wire only have about 6 ohms total.

Then I realized that Hydraraptor is using 240VAC. That seems dangerous, and in one of his posts he mentions how one of his resistors failed and ended up melting a bunch of his circuit breakers. Yikes, that’s not for me.

My plan is to set this up on an aluminum plate with the stock thermistor from the makerbot kit. I’m still unable to print because of some extruder issues, but this is a good distraction while I try to figure that out. I’m also going to try building one with nichrome wire. IF it works as well then it’ll be lower profile than this resistor configuration.