Status: In Development

Stratadue is an adapter board that connects a Duet 2 (Wifi/Ethernet) to a Stratasys 3D printer such as a uPrint (SE/Plus), Dimension 768 or 1200 (BST, SST, Elite) and possibly some Fortus machines. This board allows for complete control over the Stratasys machine, with the exception of the material bay (possibly available in a future update).

The goal is to open up these once expensive industrial machines and allow them to be controlled to their fullest potential using the Duet 2. I will be working on the development of the adapter board and making the schematic, PCB, BOM, Duet config files and macros available as soon as they are ready.

Complete details about interfacing with a Stratasys uPrint is here: https://wiki.cnc.xyz/Stratasys_uPrint_Retrofit

I'll be posting details on my build in this thread as I progress.

Pete,

Have you continued to make progress?

Would you be able to share what you have done to make the integration a success so far? For example how connections have been made between the Duet and the Stratasys boards? Have you managed to integrate the material bay in anyway?

I have been working on something very similar. The goal was to make it completely plug and play. Ethernet Duet in, while still completely maintaining the Stratasys motor controllers, thermocouplers, servo drive and dual extruders. Something that can be dropped into any uPrint and be operational in only 30 minutes or so.

Some questions I have:

How did you change from the Duet's Step / Direction signals into the PWM signal the Stratasys board requires? Did you bypass the Stratasys board to run the steppers from the Duet directly?

Similarly, how did you handle the servo motor and encoder for the extruder? Did you use a third party DC servo controller (such as Geckodrive G320X) and bypass the Stratasys electronics? Scratch that. I see you are using PICServo to adapt the signal. That's actually a similar direction I was going, but using an ATtiny85 with somewhat standard step / dir to PWM with encoder feedback. I got the extruder servo spinning, but need to flash new code to the Attiny85, which requires a high voltage programmer I don't yet have.

Here is a photo of the setup I was working on:

Chips from left to right:

(1) ADC MCP3208 that converts the data from uPrint Thermocouples into SPI data that the duet could read through the CurrentLoopTemperature code. (See code here) Check this if you are having problems getting the right TC data from the uPrint.
(2) (3) (4) Chips that convert signals from 5V to 3.3V in a bidirectional manner.
(5) Attiny85 that converts Step / Dir data to PWM with encoder feedback for servo extruder
(6) (7) (8) Attiny85 for the X, Y, Z. Takes Step / Dir data and converts to PWM for half bridge chips / microstepping.

The limit switches needed to be hardwired directly to the X, Y, Z, E0, E1 but if I recall they were not explicitly for those axis and were instead for things like light control, door open switch, locking solenoid. (I did get the Duet to control all of those things).

You are absolutely right that these uPrints are literally gathering dust and have outlasted their useful life for many of their end users. I paid $25,000 for my first uPrint brand new. However they are now popping up on eBay from time to time for next to nothing. I have bought several of them for around $300 each! The main thing holding them back was always the $200 per spool proprietary filament that greatly lagged behind the quality and innovations that were occurring in the hobby field, as well as the software that forced the best print quality to be 254 microns when DIY printers were easily achieving 50-100 micron.

The hardware on the uPrint is phenomenal. It is capable of so much more than Stratasys will allow through their software.

If you want to share / work together I'd love to help get something off the ground here. I have lots of information, pinouts.. etc written down somewhere. If I ever got it working, I'd be doing open source and conversion kits. Now that I know more people are trying to achieve the same, I'd be happy to start compiling data and code to post on Github.

@mafco77, et al

I have received a lot of messages regarding this, so I figured I would post an update here.

I have not gotten any further with the Stratadue project.

The limitation remains determining how to control the steppers and servo motors through the Attiny85. Perhaps the Attiny85 was a bad choice in chip as I am using literally all the pins for IO and that means reprogramming can only be done via a high voltage programmer. If I were to continue, I would need to swap to a device with more pins or an Attiny85 in a DIP socket.

I cannot remember, but I believe the device requires a Duet2 with custom firmware. Not sure if my changes for the multiple expansion chips was ever merged into the main code or not. It's unfortunate that Duet3 came out soon after I started working on this and it doesn't appear to be compatible either. Bad timing unfortunately!

I do have a few PCBs built, but without the Attiny85 code, and custom Duet firmware, I'm not sure it would be of much use. I still have ~10-12 uPrint printers sitting around gathering dust too! I would love to get them up and running but I believe technology has advanced so much that newer / cheaper printers are leaps and bounds better.

@NitroFreak said in Another Stratasys uPrint retrofit:

I can´t even begin to understand how you did the probing of the control board to figure out what signal goes where?
I assume you´re an electrical engineer of sorts?

I'm a mechanical engineer, but do complete integrations of electronics and software as well. As far as the probing is concerned, it didn't actually take too long. My process was mostly this:

Find where a known connection enters the board such as a motor. Find the continuity between the motor pins and the motor driver chip. Look up the motor driver chip's datasheet to determine what pins do what. Follow the traces back from there to the next point of interconnection. Eventually you find that Pins 1, 3, 17 & 19 on connector J13 are what you need to interface with to control the X-axis stepper motor by sending Phase PWM and voltage reference signals for example.

If you send the right signals there (following the motor driver datasheet) you'll get controlled movement out of the stepper motor using all of the Stratasys' built in electronics.

@NitroFreak said in Another Stratasys uPrint retrofit:

I couldn´t help but overlook that you said DIY printers can easily achieve 50 micron while the Uprint is "stuck" at 254 micron.
This isn´t quite true.
I think you missed what the strength of the Stratasys machines is.

I actually greatly understand the rock solid nature of the hardware on the machine. That's why I want to push it to it's full potential by opening up the ability to print PLA, Nylon.. etc at whatever layer thickness I want. The idea that it is dimensionally flawless is a little misguided. I had TONS of failed prints on the uPrint. I had numerous times where the part failed spectacularly in a mess of spaghetti or when the filament spooled up in the head and fused the print head into a solid block of ABS. When you're spending $50 per print, you can't have that happening.

The quality of the proprietary ABS was poorer than the stuff you could buy for $15 per spool. I had Stratasys' technicians out to troubleshoot my brand new machine and we went through every single spool of filament I had and determined each one was filled with too much moisture and had to request Stratasys replace them all. Eventually it made more sense to buy a genuine $200 roll of filament to get a new eprom and a $15 roll of a no-name brand ABS, spool it onto an empty reel and use it instead of the expensive stuff.

You can have just as great dimensional accuracy on a cheap printer. It just may not print as fast and may require more adjustment. I think you may be disappointed in the amount of effort it takes to put the Stratasys extruder on your build when compared to what other options are out there.

You may not have an easy time finding replacement parts should something break either. You'll be stuck buying used parts.

@NitroFreak said in Another Stratasys uPrint retrofit:

Anyway, the upper three points are why i want to try the uPrint head in my own printer.
What i am still missing is how to drive the 120VDC servo.
How did you realize that ?

It's fairly straight forward. Look up the model number on the servo drive. You'll find it is a proprietary part number, but the company that makes them has other similar models to look up the datasheet. You should see that the IDC 10 pin connector from the servo is a common pinout. You've got motor power and the 2 or 3 encoder signals (2 differential signals, plus ground I think).

You can hook that up directly to a servo driver, such as the Geckodrive G320X. Note: The servo does not run on 120VDC, probably something like 12V or 24V, but I don't remember off the top of my head.

The heaters run on 120VDC. You'll need a very high quality DC:DC relay to turn those on and off. Don't skimp out on that, it's some serious voltage. If you can snag two 120VDC power supplies from a Stratasys machine that would help. Note that each printer has two power supplies at 120VDC, but one is a modular supply and one is built into the main Power Distribution Board, so you'd need parts from 2 different printers.

If you are interested I designed and made a prototype head thermocouple board that takes the temperature readings from the Stratasys thermocouples and converts the signal directly to SPI. It mounts directly to the Stratasys print head. (The standard board uses voltage reference to produce the signal that must be interpreted later.)

The SAM4E8E microcontroller used on the Duet2 does have support for a rotary encoder input, but the pins are currently used by FAN2 & E0_DIR. It would likely require a hardware redesign and firmware to incorporate a robust DC servo control into the Duet... and even then, it would only be for one single motor and encoder, and you'd still need the DC driver bridge.

That's why everyone suggests selecting an all in one external option such as the Geckodrive G320X: https://www.amazon.com/Geckodrive-G320X-Servo-Motor-Driver/dp/B015TYLQ40

The G320X can take basic step and direction signals and control a DC motor with encoder all in one small package.

Whoops! Just stumbled upon this topic made just a few days ago: https://forum.duet3d.com/topic/7125/use-of-linear-output-temperature-sensors

Looks like I can use Sensor type 300. Will report back with more information for anyone else trying to implement something similar.

https://github.com/dc42/RepRapFirmware/blob/6b835cb3c8e9aa10113ae750151d9f9065116cd4/src/Heating/Sensors/CurrentLoopTemperatureSensor.cpp

Looks like MCP3204 is supported, which is exactly what I was thinking of using!

Glad to have come across your project!

I was actually working on something very similar to you about a year ago. I originally was going to do what you have done, rip out all the Stratasys electronics and then hardwire the motors directly to the Duet. It was my plan to re-use all uPrint components and not replace the print head. Then I discovered that the main board of the electronics contained the 120 VDC(!) power supply that runs the hot end as well as the various DC:DC relays needed to make things work.

I took a step back and decided that it would probably be far more effective to design an adapter that takes the signals from the Duet and converts them into commands that the Stratasys board can understand. I probed every connection to find out exact what signals were needed at each point. (Somewhere I still have them all written down I'm sure.)

I ended up creating this custom adapter board here:

As you can see it replaces the Stratasys interpretation board that converts signals from the embedded PC (now the Duet) into signals the controller can understand. Unfortunately I ran into snags with the Duet. It wasn't as easy as I had assumed it would be to assign pins to do certain things. In order to make it work, I needed to make actual changes to the firmware on the Duet itself.

While that was starting to look fruitful, I quickly ran out of time and energy to put to use on finishing the setup.

Since then, I have collected 10(!) uPrint 3D Printers with the intention of converting each of them eventually.

I am not sure if you have discarded all of the original Stratasys stuff, but if you have not and are interested in working on something that could be more plug and play... please let me know. Perhaps if you come across a second uPrint, it will be much easier without as much modification.

I see the Duet 3 is probably a much better candidate than the Duet 2 for this kind of thing as it has a bit more flexibility as far as what you can use it for.

My code for re-using the chip-select pin between multiple SPI sensors is now ready as well:

https://github.com/dc42/RepRapFirmware/pull/383/files

This change is simple and is forwards / backwards compatible with existing RRF3 configurations.

Also includes a bug fix for the CurrentLoopTemp sensors.

ajquick opened this pull request in dc42/RepRapFirmware

open Allow Chip-Select Pins to Be Used by More than One Sensor. #383

@ChrisP The goal will be to offer these as long nothing major needs to change. I also need to find a lower cost option for the Stratasys IDC connectors, they add about $30 to the BOM!

Please see the code I have committed to my fork. I am not super well expirenced in C++, but I believe this should work and not cause any other OEM's configurations to break.

https://github.com/CNCxyz/RepRapFirmware/blob/dev/src/Heating/Sensors/CurrentLoopTemperatureSensor.cpp
https://github.com/CNCxyz/RepRapFirmware/blob/dev/src/Heating/Sensors/CurrentLoopTemperatureSensor.h

Note: I implemented the addition of parameter "C" to be the channel on chip. So values from 0-3 for MCP3204 and 0-7 for MCP3208. Default value is 0 (CH1).

I figured in Hex that the default CH1 was 0xC0, with each additional channel being the addition of 0x08. So I did a simple equation to multiply the channel on chip number by 0x08 and add it to the default 0xC0 value. I am 99% certain that is valid C++ code, but I am not absolutely certain if mixing hex and decimal will yield a valid uint8_t value?

I did not integrate Differential signaling as I was not 100% certain what parameter to use in the G-Code. Wn? W0 for Single, W1 for Differential? Such a change could be implemented very quickly.

Let me know if this checks out and if you would be able to merge this with the code base for the next release?

@motomo Can't provide a Gerber as that was a prototype that didn't work.

@sebkritikel if you want to get super involved you can plug a keyboard and monitor in directly to the onboard PC inside the machine. If you run a few commands (I'm guessing sudo systemctl sshd enable) you can actually enable the SSH access into the machine and have full access to the files and commands. If I recall the hard drive contained the executable code for every model they had (Dimension, uPrint, Fortus).

You can also plug in over serial and send commands that would mimic the ones sent between the material bays and the controller. (Probably different for a Dimension or 1200 unit.)

@sebkritikel I know there are some technician only software tools out there that allow you to actually adjust the settings on the 1200/uPrint. I believe over command line you are also able to see some of those speed and acceleration parameters. That being said, I think the uPrint for example is very de-rated as far as what it is actually capable of. I would expect having to adjust the speeds and accelerations after conversion.

@archeantus Ahh that all makes sense. My first test was to do something similar. I had a Geckodrive G320 installed, several AC relays and made direct connections to the motors. I only abandoned that idea after I found one of the 120VDC power supplies was located directly on the PDB.

Using both seems to be the easiest solution.

@archeantus said in Another Stratasys uPrint retrofit:

Hey, I wouldn't have been able to get where I did without your work. Would you like to be added as a contributor to the project?

I've got a Hackaday account now, not sure what that entails: https://hackaday.io/ajquick

@archeantus said in Another Stratasys uPrint retrofit:

@aj-quick I run the motors directly from the Duet.

Would you be able to explain more? Mainly just what connections on the Duet are made to the PDB for the motor control? From the drivers directly? Any bypassing of the drivers on the PDB already?

@archeantus Absolutely impressive!

I would like to know how you have controlled the stepper motors directly from the Duet though the PDB. As I remember it, the onboard drivers take a PWM sine signal for control instead of regular step signals. Did you work out another way to do it using the Duet drivers directly!?

@mafco77, et al

I have received a lot of messages regarding this, so I figured I would post an update here.

I have not gotten any further with the Stratadue project.

The limitation remains determining how to control the steppers and servo motors through the Attiny85. Perhaps the Attiny85 was a bad choice in chip as I am using literally all the pins for IO and that means reprogramming can only be done via a high voltage programmer. If I were to continue, I would need to swap to a device with more pins or an Attiny85 in a DIP socket.

I cannot remember, but I believe the device requires a Duet2 with custom firmware. Not sure if my changes for the multiple expansion chips was ever merged into the main code or not. It's unfortunate that Duet3 came out soon after I started working on this and it doesn't appear to be compatible either. Bad timing unfortunately!

I do have a few PCBs built, but without the Attiny85 code, and custom Duet firmware, I'm not sure it would be of much use. I still have ~10-12 uPrint printers sitting around gathering dust too! I would love to get them up and running but I believe technology has advanced so much that newer / cheaper printers are leaps and bounds better.

@archeantus Very interested to see what you have accomplished!

This project is currently on hold. I had to go back to work on other things.

I have not yet ordered a new revision of the hardware as I need to make sure that the Attiny85 is actually capable of driving the servo and steppers in a robust manner. I worry that the processing rate of the Attiny is not fast enough for the servo motor. Tuning is very difficult. I have some control over the servo in a closed loop, but am worried about lost steps, overshoot and oscillation.

The latest design. Hopefully will be assembled and in-hand by the end of next week.

So many little changes between this version and the last. Namely: The Power Enable now uses a MOSFET to supply higher amperage to the Stratasys PDB.

New features:

-Control over the printer's main power supply. If the power switch is flipped off, the board will be able to keep it alive and go into a controlled shutdown. The Duet will be able to turn itself off in a controlled manner.
-Head Thermostat signal. There is an internal thermostat inside the printer's head that will trip if temperatures exceed a set point (100 degrees C). This is in addition to the head and chamber temperature alarms, and the three thermocouples.
-Bed Level Probe has an enable / disable. As it turns out you can turn the bed level probe on and off, so that it is only detecting when it is going through the bed leveling routine. This was discovered and added to this revision. Previously the bed probe was always enabled. I believe the reason for this is that the bed probe uses the signal to determine when the probe is stowed and then when it is sensing the presence of the bed.

Finally all uPrint printers (and presumably Dimension and Fortus) have a secret Machine ID eeprom located on the main body of the machine. This eeprom contains the serial number of the printer and the type of printer. On Stratasys machines, the hard drive contains the code to run all models of their printers. The eeprom tells the on-board computer what software to run. I found that the eeprom runs on a serial data bus, which the Duet2 has available. I figured I would breakout the signals and include an area where the signals could be read by the Duet2 should the need ever arise. The signals are by default not connected, but can be added by bridging the solder joint.

My thought is that it could be possible for the Duet2 to read the eeprom and verify what type of machine it is plugged into (uPrint, Dimension, Fortus) and then load the appropriate configuration. It is completely unnecessary though.