Electronics #1

At this step we can test if the XYZ axis are moving properly. Lets mount all the electronics on the frame. As I have plywood frame with supports, I have some place to mount arduino directly to support, and as well I can make a holes for the power supply.

There will be more photos than usual.

Printed parts needed:

4x arduino-washer

At first, I checked where i have to make holes for power supply by temporarily apply it to draw points for two holes, and use 3mm drill on it.

IMAG1533

IMAG1534

For this mount I’ve used M3x20 screws, but even M3x15 with 9mm frame should be enough. It fits, and its stable.

On the other side of printer will be arduino with ramps. Lets make the sandwich.

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And mount it on the frame… Using M3 screws and Arduino washers from i3 Rework.

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The length of screws depends on your frame thickness, for 9mm frame I’ve used M3x18 screws.

Then, some soldiering are needed (depending on types of cables, some motors already have the proper cables, so only for endstops soldering are needed)

IMG-20170403-WA0004.jpeg

For the endstops I’ve used the NO output (as I want to have a signal from endstop when it will be triggered).

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IMAG1600

Endstop COM -> Ramps GND (-)
Endstop NO -> Ramps S (Signal)

But the connection doesn’t matter at all, as long as it will be between GND and S, otherwise the Configuration for Marlin which I provide will be not working.

After connecting everything as in any build with RAMPS 1.4 we can move to the computer and make the first tests. If You are not familiar with the connections, take a look on THIS – its complete guide for wring the RAMPS 1.4, even with power supply.

For connection between power supply and arduino use 2×2,5mm cables, to decrease probability of fire, especially with wooden frame 🙂

Software part requires:

Arduino IDE
Marlin firmware
USB A to B cable (You should get one while buying arduino, or You can take from the 2d printer, as its commonly used there)

If you don’t want to configure marlin by yourself, You can download the version which I made, but keep in mind – all your mechanical parts MUST BE same as the ones covered on that page. I changed the stepper driver on Z axis to DRV8825 with 1/32 stepping, so You have to do it also (or wait until I will change the DRV8825 to 1/16 mode, as I am planning that – the original has also 1/16 mode on all steppers).

Install the Arduino IDE, and open Marlin.ino file from the downloaded firmware. It will open a lot of tabs inside IDE, but for us currently interesting is only the Configuration.h.

What we have to do right now?

Lets configure the steps per mm – its the amount of signals needed to send to stepper motor to move axis by 1mm. Prusa made a great calculator for that – its available HERE

We have 16 tooth on our GT2 pulleys on X and Y axis

xysteps

And we have trapezoidal screw with pitch 8mm.

zsteps

We need to enter that values to Configuration.h – lets hit Ctrl + F for find, and look for “STEPS_PER”. It should find a entry somewhere in the file.

Modify that line with results which You got from the Prusa calculator

arduino001

And its ready!

Connect the Arduino to PC and click on the right arrow in toolbar, and wait… It will show the status on the bottom of Arduino IDE window, it should finish correctly.

After that, its ready to test. Install Repetier-Host or Prointerface (maybe you had already one of them), and try to move X, Y or Z axis, connect your power supply to network, and lets start testing!

Be careful! For Z axis do only small moves (0,1) and watch carefully if both motors are spinning in same direction. If not, reverse the cables for one of motors. If any axis is working in wrong direction – also reverse the cables (or, modify the Configuration.h and reflash arduino – if You know that way).

Stay tuned for the extruder assembly. The build is getting closer to finish!

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8 comments

  1. I’m impatient to see what kind of results you will get with your clone! If it’s good I’ll probably build one as well. I already have a chinese Prusa i3 and I’m thinking about upgrading it following your instructions.

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  2. I am in the middle of building a clone using mostly similar parts. I would really like to know if you had issues lining up your extruder motor with the larger mk8 gear than the original MK2? I noticed my gear covers up the entire path for the filament when looking down through the hole and the motor cannot be shifted over. I might redesign the piece with the holes moved over slightly.

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    1. I will be assembling the extruder next week. From quick check on the Chinese MK8, I don’t see difference (apart from color) comparing to the original. As I saw on Tomas Sanlanderer video of building cheap clone, there should not be any problems with the Chinese extruder gear.

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  3. Thanks for replying – I’m going to have another look tonight and see if I wasn’t just misaligning something, somehow. I watched his video series as well and though he had to drill his holes out slightly to align it, his looked much more aligned than mine. If I look from the top down I’m seeing at least 3/4 of the inside diameter (2mm) of my PTFE tube is blocked. 😦 Good luck with yours!

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  4. Hey – really sorry to keep posting here but figured I’d let you know – I compared my MK8 gear to my buddy’s stock MK2 gear and there is a significant difference. The effective diameter of the prusa hobbed bolt is 6mm while the MK8 is upwards of 7. I modified the parts necessary to accomodate it and have it installed on my clone right now, it’s working well. 🙂 If you’d like to download them they are here: http://www.thingiverse.com/thing:2258341

    Cheers!

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    1. After few prints with the extruder-body from original, I must admit that you are right !!
      Thank You very much for the model, I’ve printed it, and it works excellent!
      I will be recommending Your model for that build, as it fits perfectly.

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      1. Glad to hear the parts came in handy! Yeah I thought my alignment would be fine too but then I was having issues properly extruding, which set off some red flags. Good to hear everything is working! 😀

        Liked by 1 person

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