PSMD (Pololu Stepper Motor Driver) Triple Axis Driver

by tinkerings, published

PSMD (Pololu Stepper Motor Driver) Triple Axis Driver by tinkerings Oct 23, 2010


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A drop-in replacement for the MakerBot stepper drivers that contains all three axes on one board.

You can order these from my web site: http://www.tinkerin.gs/p/psmd-pololu-stepper-motor-driver-triple.html
Now you can also order these from Seeed Studio!: http://www.seeedstudio.com/depot/psmd-triple-axis-driver-p-1029.html

Updated: Now smaller (same height as a Gen4 stepper driver and 1/4" wider for 3X the axes), and with dip switches to configure microstepping. Also now has a motor-power-in (or 12V out) screw terminal that can be used to drive the motors on up to 35V. I need to update the files an description.

See it in action here (with an early prototype): http://www.youtube.com/watch?v=8TEvwzTABEI&hd=1
And it's not mentioned or shown, but you can see it in action in this video: http://www.youtube.com/watch?v=2iGnlqBLn5s&hd=1

This board makes your steppers run at eight times higher resolution (1/16th steps instead of 1/2 steps), making it run smoother and way quieter.

I based the design on the MakerBot Stepper Driver v3.0 ( http://www.thingiverse.com/thing:760 ) but with a few notable exceptions:

•) I used the Pololu A4983/A4988 ( http://j.mp/pololu-smd2 ) stepper motor driver carrier board for each axis, so three of them are required for all three axes to work. (This was originally designed fo the A4983, but the replacement A4988 works great.)
•) Circuitry that is already on the Pololu board has been removed.
•) The CD-ROM-style connectors from the Gen4 electronics are used. I used a horizontal-mount connector instead of a vertical mount for mostly cosmetic reasons on the Cupcake, and that may have to be changed for the Thing-o-magic or a RepRap. I'll have to modify the layout to support vertical connectors if they are needed.
•) This board is etchable and hand-solderable. This means that, with the exception of the thru-hole capacitor leads, none of the lead holes are used as vias. Also, traces are reasonably far apart, all of the wiring of the thru-hole parts (except the caps) is on the back, and vias (and drilling) are avoided as much as possible. I have provided the PDF I used for toner transfer.

I placed the Pololu boards vertically and with nothing under them to provide a natural flow of hot air past them. This is why the capacitors are mounted on the back. If they still show signs of overheating, there are holes at the bottom to mount a 12v CPU fan to blow air up past them and provide cooling. So far, in my testing, the steppers overheat before the drivers.

More info about the RepRap testing with Pololu drivers (and my inspiration) here: http://www.reprap.org/wiki/Pololu_Electronics

Update 1: Oops, I forgot to post my machines.xml. Now it's up.

Update 2: I added a photo of this latest revision with the endstop connectors corrected and soldered in place. I'm working on the mechanical endstops as another thing. All of the other photos are of the previos revision of this board. Update 3: I updated the eagle files with some minor cosmetic changes, mostly to clean up the silk screen. I didn't change the version because it's all cosmetic. Update 4: I have partial build instructions up on Flickr. http://www.flickr.com/photos/giseburt/sets/72157625473951054/ Update 5: I have updated the design a little, and bumped the version number to 0.5. (I've left the 0.2 files here.) It now has 6-pin connectors that should be compatible with the Gen4 electronics. It also has a 12V in/out screw terminal, and I've added more silk-screen to help identify parts and pins. The down side is that the -pin connectors made the traces really tight, and it will be more difficult to solder a home-etched version, since some traces to the 6-pin headers are on the top side. I'm sorry, I'm currently out of kits. I am in the process of having some professionally made, but I don't currently have an ETA. The good news is that they will be completely assembled, and the only soldering needed will be of the Pololu drivers.


For assembly of the older (pre-v0.6) boards, follow the directions at http://www.flickr.com/photos/giseburt/sets/72157625473951054/ keeping in mind that there are a few changes from the PCB shown that are explained in the descriptions.

Mount the capacitors on the back, and if you're etching a board yourself, you'll need to solder the legs on both he back and front. Those are the only place I did that.

I recommend soldering all of the surface mount stuff first. It's hard to get to with the headers an stuff in the way. This is the 13 LEDs and 12 resistors if you're not doing the extra power circuitry. There are all large-pad (non-pinned) SMD parts, and are easy to solder by hand. Technically, the LEDs and their three resistors are optional, but very helpful to see what's happening.

The LEDs are in groups of two, from top to bottom. Each group of two should have one oriented one way, and the other the opposite way. So, for example, the top two would be red, one oriented to the left, and the other oriented to the right. From top to bottom, it would be:
1) Red Led (to the left)
2) Red Led (to the right)
3) Green Led (to the left)
4) Green Led (to the right)

1) Red Led (to the left)
2) Red Led (to the right)
3) Green Led (to the left)
4) Green Led (to the right)

1) Red Led (to the left)
2) Red Led (to the right)
3) Green Led (to the left)
4) Green Led (to the right)

Installation - once everything is soldered and checked for shorts. I put the labels as X, Y, and Z from top to bottom, but that really doesn't matter. Each of the three are independent, and you can make them whichever axis you choose, so long as all of the connectors for each axis are matched horizontally. 0) If you're installing this on a MakerBot cupcake to replace the stock drivers, remove those first. 1) Place the Pololu drivers in the three sets of female headers, with the trimpot (little screw) to the top. 2) Mount the board. On a Cupcake, the mounting holes match the tops (or bottoms) of two consecutive standard drivers. (To do: Add a photo of it mounted so this makes sense.) 3) Connect the steppers. You can at this point decide which of the three circuits (horizontally) are for which axis. I did Z, Y, X, from top to bottom, so that my stepper cables where not too stretched. The notches on the stepper cable should be toward the plastic fingers on the connector. (If you're steppers move backward, you can probably flip them, but it's better to do that in software.) 4) Connect the ribbon cables. They have notches so you can't get them backward. Just be sure that the ribbon cables are horizontally next to the correct steppers. 5) Connect the power, at the bottom. 6) Note, this changed for ReplicatorG 22. On ReplicatorG 22 or higher: Download the file
makerbot (3-axis pololu).xml
and move it to the
folder of the ReplicatorG folder. Now open ReplicatorG and skip to Step 8. On ReplicatorG 21 or lower: Install the machines.xml file. (ReplicatorG should be closed for this part.) It goes into the folder ~/.replicatorg/ (~ means your home directory. On OS X, hit Cmd-shift-G and type that in, then hit return to get to the folder, since it's hidden.) Be sure to make a backup of your old one first. If you're not connecting to a Cupcake, you may have to edit the file appropriately. This file if to account for the steps being 1/16 steps, versus the 1/2 steps with the normal drivers. 7) (No longer needed for ReplicatorG 22 or higher.) Open ReplicatorG and go to Preferences and check "Show experimental machine profiles" then click Close. 8) Under the Machine menu, choose ReplicatorG 22 or higher:
Driver → Cupcake CNC (with 1/16th step Pololu Driver)
, or ReplicatorG 21 or lower:
Driver → EXPERIMENTAL - Cupcake CNC (with Pololu Driver)
9) Now connect to the machine and test movement with each axis. You should now tune the trimpots for each axis. 10) Print! Tuning the trimpots This is the same as with the standard drivers, except the trimpots are a lot smaller. 1) Turn all three of the trim pots all the way to the left. This turns them all the way down. 2) In ReplicatorG, open the control panel and click Steppers On. 3) Now, slowly turn each trimpot to the right until you can no longer move the X and Y axes by hand. Don't push real hard, you don't want to break anything. If your belts skip, then you probably need to tighten them. Be sure to push the X-axis by the middle instead of the front or back so that you don't do any damage to the rods or the bushings. When it was at the right place for me, the steppers squealed audibly, so I went past the squeal and stopped. 4) Do the same with the Z axis, except move it up and down with the control panel until it appears to move smoothly without any binding stopping or slowing it. The goal is to have them as low as you can so that your steppers don't overheat during long builds, but no so low that you gets skipped steps. If your steppers overheat, they will lose their power (and skip a lot) until they cool back down, so don't try to adjust anything until they've cooled. If you're getting skips during prints and the steppers aren't really hot, turn the appropriate trimpot up a very little and try again. If you find that the drivers themselves are getting hot, you can add a small 12v fan at the bottom of the board with some twist ties or pull ties. I recommend pointing it up to blow past the drivers and draw the most heat off. I haven't had to do this and don't know how well it works. Enjoy!

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A note for anyone mounting these things, you should use a longer screw and use either 2 washers, a longer nylon spacer than what comes in the kit, or a 3mm nut to provide proper spacing for the underside capacitors. See attached image for what I'm talking about.

Will this work with the mechanical endstops from makerbot? I'd really like to install some after an accident I recently had using Multiply. Do I need to use special firmware for endstop usage too?

No. Whatever endstops your motherboard supports this just passes the signals along.

Not that one Gen4 motherboards this does not send the signals along, but instead you connect the endstops directly to the motherboard.

If you are using a 3G 5D Shield with a Gen3 motherboard, then you need to pay attention to which version of the Shield you have. If you bought the 6-endstop ver
sion (the kind in the MakerBot store) then you can use all six endstops, and the firmware for the shield will handle that already. If you have the 3-endstop version then you can only use one endstop per axis, but it doesn't matter which one.

Also note that when using this with a 3G 5D Shield on a G
en3 motherboard, you can connect the endstops to either the shield or the PSMD. You can even connect some to one and some to the other. BUT DON'T connect two endstop switches to the same port of both the Shield and the PSMD, or when one trips it will short out your bot!


I bought a board back in Feb. but never put it together. I just bought your new version a week ago and put it in a few days ago. My cupcake is so quiet now! I used to close my office door so I wouldn't wake the kids while printing, now I don't have to close the doors because I can hardly hear it in the office! Thanks!

I have these available for sale now:


They are $45 for the first one, $40 for each one after that.

Seeedstudio will be carrying them next week as well.

Seeed Studi is now carrying these as well, so add one (or two) to your next Seeed Studio order!


They even throw in three 10-pin IDC connectors.


There's currently a "are you interested" thread going on over on the MBI google group: http://groups.google.com/group/makerbot/browse_thread/thread/94e8be5619a82f0bhttp://groups.google.com/group...

Anyone who's wants in on the pre-order should post up over there.

I would love a kit! What is the status on the new boards?

How do I get one of these kits?

These look fantastic. Please let me know when there's a kit available. I'll gladly pick one up to smooth out my Cupcake.

When you get kits in, please let me know. I am interested.

I am looking into buying a kit, how much?

Looking into a kit, I was looking at the 4 axis boards but the maker involved doesn't seem to be replying... I might end up just using 3 of the 4 pololu's I bought on this, then a makerbot stepper driver to drive the extruder :P

I have a few on hand. They're beta-kits, so I don't buy many of them, but I'll sell you one if you're interested. (I upped the price $10, but the SMD parts are already done.) I also have the Pololu drivers to sell with it, if you want.

Oh, wonderful! I was kind of holding on to using the 4 axis board that was here, but I realize now it would be simpler to use this as well as

...hold on a sec...

Mid-typing this message I realize that my new email client I've been messing with may have actually failed to send the messages at all. One moment...

Ah, well anyway. It would probably be easier to drive on this + a standard makerbot stepper. How much is the price now again?

Any chance at all of purchase?

Yes. I'll reply directly with more info.

Arrived today, thank you very much!

Hmm, not working on the first try, but I'll have more time to mess with it later today. I fear it may have been excessive use of solder flux... but I really don't know @[email protected]

Make sure the jumper is set or the 12V light won't light and the motors won't have power. That's most likely the problem.

Sorry I ran out of jumpers to put in the kits, but you might even be able to solder it if you don't plan on using another power source.

Nah, set the jumper. I just got it working, in one direction only though. I just immersed it in warm water and am currently drying it (to clean solder flux) and I'm going to try touching up the soldering a bit.

Arright, found the problem. It was half that the machines.xml wasn't updated correctly, and half that one of the drivers was malfunctioning. (luckily I thought I was going to buy a 4 axis board, so I had a spare right there) Spent a half hour on trimming the trimpots exactly, now it's... almost silent.

anyone know what the machine settings are when using this driver and acme rods?

Sorry that no one has replied yet. If you figured it out, could you post them?

Otherwise, the scale setting in Machines.xml should be the same as for the standard Cupcake/Gen3 drivers with Acme rods * 4. (Gen 3 is 1/2 microstepping, and these are 1/16th.)

Wouldn't that be * 8 then?

Oh yeah.

From Gen3: x8
From Gen4: x2

How did you export the pcb so its double inverted (black paths and black outer layer) and etchable? I am attempting to make my own modified version of your board except using 3 of these http://www.robotshop.com/pololu-8v-35v-2a-single-bipolar-stepper-motor-driver-w-regulators.htmlhttp://www.robotshop.com/polol... Hopefully I can finish it tomorrow :-D

This thing rocks! Thanks tink =-X I managed to etch a single sided board (first time) with the LED's and endstop removed. It works great and the printer is very quiet now.

I would also love a board or a kit dosent matter! Please pm me when the become available

Same here. I have the Pololu carriers on order. I hope to have a board for it before it arrives. :-D

I'm sorry guys. I just placed an order for a small amount of a new design, and will let everyone know as soon as I have them in and they're tested.


any reason why this can't be used on a Mendel setup?

As long as it's used with a MakerBot Gen3 or Gen4 motherboard, I don't see why not.

I know of at least one Mendel using this board. :-)


Anyone know where I can get the Pololu stepper board in the US? Pololu has been been out for a while and I can't find stock any where else.

There are some of the people that carry them, and sometimes have them in stock when Pololu doesn't:

MakerGear: http://www.makergear.com/products/plastruderhttp://www.makergear.com/produ...

UltiMachine: http://ultimachine.com/node/402http://ultimachine.com/node/40...

RobotSimple: http://www.robotsimple.com/A4983_Stepper_Motor_Driver_Carrierhttp://www.robotsimple.com/A49...

RobotShop: http://www.robotshop.com/pololu-8v-35v-2a-single-bipolar-stepper-motor-driver.htmlhttp://www.robotshop.com/polol...

I have only personally ordered from MakerGear, and am very happy with their service. I don't have any experience with the other vendors.

They are all out of stock too... guess I'll just have to endure the loudness for a few more weeks.

I second that comment about MakerGear. I bought a few things from them and they have awesome customer service!

Would really really love a board or a kit.. dm me and I will paypal away!

I am interested in a kit. how do I contact you?

Do you have any more boards available? I would love to purchase your kit...

Holy crap! I can't believe how quiet my Cupcake is, now that I finally got around to installing this Thing.

Very well done, Rob!

This is next on my list of Makerbot Major Upgrades. I think it's time for me to go microsteppin'.

Well then of course I'll have to keep the old drivers handy for when I want to distribute music throughout the house. And to the telephone. ;)

Built mine over the weekend and it works great. It probably reduces bot noise by 75%. Many thanks. The only mechanical issue I had was that when I first tried the board, it was dead. I quickly realized that I needed to set the power jumper, as opposed to having made some horrible soldering error.

I've hit one other issue, probably of my own doing. Instead of 1/16 stepping, I'm sometimes getting (what appears to be) 1/2 stepping with one of the three blue connectors for the rainbow/ribbon cable (the one marked for the Z-stage). I've re-arranged cables, swapped Pololu boards, and switched steppers, but the only constant seems to be board. Most likely, I screwed something up while soldering. This is an inconsistent problem. Sometimes I get 1/16 stepping, sometimes (after restarting the bot) I don't. I've gone back to using my Makerbot stepper board for the Z-stage, so I'm only using 2/3 of the kit at the moment. Any suggestions in diagnosing the issue more precisely?

The three resistors on the back, near MS1, MS2, and MS3, are the ones that set the micro-stepping. If they are not soldered solidly, you'll get the behavior you're describing. If there is a "cold joint," which means it looks like it's soldered but it is really just touching, when it gets warm or with vibration it'll come loose.

I suggest running over them with a soldering iron again, perhaps with a small amount of fresh solder. Use solder flux if you have some.

If you are still having trouble, a close photo of those resistors would be very helpful.

You were right on the money. I'd tried adding some additional solder to them previously, but after reading your suggestion I decided to pull them off the board and start again from scatch. The result: It's been running without problem for several days now.

Me Too! I can see the Kit's are $60 but I just need the board. Can you sell just your board?

Thanks for all your work!


Oh, yeah. The boards by themselves ar $10 each + $5 shipping.

How do I order just the board?

Great, I'd like two. Will you email me directly at [email protected]


only you can provide me the card and list of

components for me to ride home?

contact me by e-mail [email protected]

I am looking to purchase one too if you still have any left.

do you still have these for sale?

Why yes I do! I'll DM you with contact info..

thanks, money sent... cant wait for the quietness :)

dumb question.. does the kit come with the pololu boards?

No, that's not a dumb question. It's actually very important.

No, the kits I'm selling do not come with the Pololu boards.

Finally built mine today and it's up and running now! Quiet and smooth, working great! I only did a 20 minute print but the stepper boards never even got warm. Time to pull my 3 stepper boards off !

Here's a link to a video with the camera inside the Makerbot to show how loud everything is:

http://www.flickr.com/photos/[email protected]/5294152105/http://www.flickr.com/photos/4...

If anyone's interested in a kit of this, and you're going to Botacon 0, I'll have a few of them with me. Contact me for details.

Discovered this a bit late, but put me down for a PCB or a kit if you make another run, thanks.

I've got about a dozen kits right now. I'm charging $60 + $5 shipping (to most places, USPS). Let me know if you're interested!

I'm interested.

does it have endstop connectors? I'm considering making a seperate endstop board.

Yes, it has endstop connectors. They use the CD-ROM style connector of the Gen4 electronics. I added a photo showing them in place.

The endstops will be a different thing. I'm working on them still.

"The endstops will be a different thing. I'm working on them still."


I'm working on a different Thing that will be both the Endstop circuits (95% the same as the Gen4 MBI ones, except etchable and with places on both the front and back for the LED) and various printed pieces that hold the boards int the correct position and make the endstops adjustable.

wait, could you make a printable version of the connector on the board side, that fits over standard pin headers?

How about adding one more controller for a stepper based extrude motor? It seems there is interest in heading that way.

If anyone sells this as a kit I'll definitely buy one.

You can put my name on that list as well.

I'm interested also.

Let me (us?) know a total price, but I'm probably in.

I plan on selling kits. (Actually, I was hoping to find a reseller, shipping being the pain that it is...) I still don't have a price.

I ordered my first batch of 10 to make sure everything is looking good. I have no idea how much demand there is for this, so I might keep it to batches of 10 for now. Unfortinately China is getting hit hard by Christmas shipping and it may be a month to get these in. If people are willing to pay a
premuim (~$20 for the board alone) I might be able to get the shipping via FedEx or such. It triples the cost of the boards to do that. Once this first batch is done, I can charge less.

I'm not sure of the pricing yet for the kit. I'll update the thing when I know.

If anyone else is interested, p
lease comment or contact me so I know about how many I need to order.

I'd be down for a kit if more are planned.

I'd like to be on this list too.

Have you thought about having Rick at Makergear carry this as a kit?

Yes, I have. I even sent him one for evaluation. :)

The ultimaker guys will be coming out with a very similar kit 'soon' (soon as in: the boards are in but still hold a minor schematic design flaw) That board has room for 5 pololu stepper drivers, 3x 50A pwm fets, 6 limit switches, and some connectors for a lcd interface. It all connects to a arduino mega board as the normal arduino has to few io and memory. The final price will be around 30 EUR.

I'd like to be put on that list!

In case you have a spare PCB, would you sell me one? I could paypal you the money.

I'm not very good with circuits, but would it be possible for this to just have one power input? I mean its all coming from the same source anyway, so why use 3 plugs?

from what I see (terrible guess), those are connectors for the motors.

Hintss is correct, the connectors on the left of the green boards pictured (the Pololu drivers) are where the steppers get connected. To the right of them is where the ribbon cables coming from the motherboard are connected.

There is one power connector at the bottom of the board. It powers all three steppers (12V) and their drivers (5V).

This board is awesome and I hope he wins for the improvement Thingiverse contest! Here is a short video showing the board in action. It really quieted things down even before a Mendel inspired X stage (which I am going to print)! It also seems to be affecting resolution in a good way!


Excellent board for the purpose!! Keep up the good things on thingiverse!

I personally have migrated totally away from MBI electronics on my MakerBot, and I like seeing other people begin the transition.. Maybe they'll take note. :-E

thingomatic has everything on one board, like huxley. you may have to redisign the whole board

Last time I looked the 4th Gen electronics had stepper controllers with 1/8th step drivers. That could have changed.

I did see in the GitHub that there's a "Machine Controller" in the works, but I think that'll be 5th Gen at least. I could be wrong.

also, a suggestion: a GCode for those that have a unicorn pen plotter

Oh!! I see! You mean so that someone can solder resist with a unicorn to etch one...?

I'm not sure how to do that just yet. I'd have ro look into it.

I do know that you can open the PDF that I made in Inkscape. From there you'll have to remove the extras and print one side at a time. Registration of the front/back will be the biggest challenge, most likely.

If anyone does this,
I'll happily post the gcode here with credit. Also, I welcome derivatives.

IIRC, the etch resist is a layer of ink/toner/whatever, to create traces in acid etching (put resist on, put in acid, wait a while, remove from acid, rinse, remove ink/toner/whatever). also, just found this: http://www.wikihow.com/Etch-a-Circuit-Boardhttp://www.wikihow.com/Etch-a-... and the only difference would be the use of a machine instead of hand drawing it.

I really don't understand this comment.

Using this wouldn't require any different GCode. Other than the machines.xml (and choosing that profile) there shouldn't be any difference in the usage.

I meant so you could make the etch-resist on a makerbot, if its small enough