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QuoteDust
Did you use their digital names? (if is still the same as )
Your incredulity solved my issue. I was the first Google image for "atmega1284 arduino pins," which gave me a MightyCore pinout. It matches the pinout on RepRap wiki as you mentioned, so I guess it was compatible with arduino mega.
It turns out that Melzi is based on Sanguino (so, an arduino clone), and exploring the prop
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lhartmann
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Reprappers
Anyone knows where can I find them?
I'd like to hack mine not to use the servo connection anymore.
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lhartmann
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Developers
Got a BLTouch clone, mounted it to my i3 clone, connected it to a Melzi clone, git cloned Marlin, and Dolly is not doing well.
The probe does not deploy when I try to use A1-A4, SDA or SCL as servo pins.
It works nicely with TX1 as servo pin, but I need if for TTL Serial (Octoprint on OrangePi).
I assume (from RAMPs schematic, but untested) it should also work with some of the SPI pins, but t
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lhartmann
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Reprappers
I have an i3 clone (prusa i3 improved for laser cut by twelvepro, i believe), but would like to have an enclosed build chamber for ABS prints.
Could you point me to a DIY printer model that is fully enclosed?
If possible I would like to reuse my mechanical components.
I also have access to a laser cutter, so it would be nice if it is mostly cut panels.
Thanks.
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lhartmann
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General
Looking great! Looking forward to see it printing ABS, the chamber hopefully helps.
Which is most problematic for the print volume? Carriage or effector dimensions?
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lhartmann
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Delta Machines
The SS14 on the 3.3V supply was the to protect against ATX 3.3V feeding back. You should probably remove the diode AND all connections to the ATX3.3V. They are not needed since you will have +5VSB anyways when the power supply is connected.
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lhartmann
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Developers
Took a look at the schematic, looks very promising! Found 3 potential issues, in order of importance:
Spi address demux seems wrong. Aren't gate signals opposed logic levels ANDed together? If so setting all high or all low are both disable.
The SS14 diode after the 3.3V regulator may cause the voltage to drop under 3V when USB/standby powered. Could it be an issue?
Finally to put my OCD at e
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lhartmann
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Developers
Quotenathan25
It would be nice if we could use one chip instead of 2, but I'm not aware of an ARM chip out there with a good development base that has WiFi and enough pins.
Texas Instruments CC3200?
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lhartmann
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Developers
I saw someone using P-MOSFETS as low-loss reverse polarity protection circuits.
You may be able to use some to protect against 24/12V mismatch.
Granted you will have to find MOSFETS large enough to stand the full current of the printer...
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lhartmann
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Developers
Very interesting!
Maybe you can incorporate the microcontroller part of the code on a SBC Linux computer (random-fruit pi) by using the I2S shift register output hack.
Everything, from openscad to stepper control, could run on a single processor. This would be lovely since half my failed prints came from communication failures.
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lhartmann
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Firmware - experimental, borrowed, and future
ONE arm with regular bearings on the effector.
TWO arms with ball joints on the effector.
ALL arms with ball joints on the rails.
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lhartmann
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Delta Machines
I was considering that vertical offset of arms too. It would work on the carriages, but if we use regular ball joints then the hotend would spin freely around its own axis, changing height in the process. In other words, it would be underconstrained.
You could fix it if one of the arm sets was coupled with regular bearings, free to rotate vertically but locked horizontally. Math would deviate f
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lhartmann
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Delta Machines
Yes the idea is pretty similar to the tiko 3d, but without the fancy design and kickstart scam. I got to it while struggling with a heated chamber for my el-cheapo i3 clone, i saw a huge PVC pipe on a hardware store and thought it would make a cool heated delta.
Originally I thought about no doors on the base, maybe not even rails all the way down. I was thinking of having the print bed detached
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lhartmann
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Delta Machines
Doing some modelling on OpenSCAD... I have a feeling we could hide the belts inside the V-slot profiles, just using a GT2-16 pulley on top and a couple of 623 bearings on the bottom (or one of those toothed idlers). This should put the belts deep enough to clear the rollers, and would make it look like the carriages are moving by themselves.
Also found this guy on thingiverse that used PCBs as
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lhartmann
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Delta Machines
Pricing is exactly why I considered PVC tubes, they are 1/12 the price of similar acrylic ones: R$ 600 buys 6m x 300mm x 4mm PVC, or 1m x 300mm x 2.5mm acrylic.
Maybe building most of it in pvc, and a 20cm section on acrylic as a window on the base? Anyways, PVC + sandpaper + spray paint yields some nice looking things too.
If I wanted to keep this idea to myself then I would not have posted it
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lhartmann
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Delta Machines
Yup we have a PCB CNC mill based on something that looks like MGN12, it is crazy accurate! Pricewise, though, a single 500mm guide with skate is as expensive as all three columns and rollers using 20mm V-slots.
Can we really use all the extra accuracy of the rails on a 3D printer? Feels kinda weird attaching high end linear rails on a sewer-rated PVC pipe.
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lhartmann
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Delta Machines
When you say rails you mean like hywin or v-slot extrusions?
Anyways, that is a great idea. They are both probably much easier to mount. We could just screw directly to the tube, no printed mounts required.
As for the tube diameter I mentioned 300mm for it is easy to get here. If we use a parametric design tool such as Fusion 360, FreeCAD or OpenSCAD, then nothing stops us from changing the dia
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lhartmann
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Delta Machines
I was thinking something like this for the bottom supports. 3x M3 bolts+nuts, 2x 8mm rods, 2x 623 bearings on the center for a pulley.
I was just wondering how far apart should I make the 8mm rails so I could use other printer's parts with minimal modification.
Also where exactly to place the belt bearings.
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lhartmann
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Delta Machines
Actually the tube was supposed to replace all the aluminium extrusions, a PVC tube that thick is quite rigid.
The tube would also be open on both ends:
- The bottom you place over the printbed when in use. You get a removable printbed as a bonus, but requires auto bed levelling.
- The top should be a cover to hide the filament spool(s) inside the printer. Bonus: Heated filament storage for PVA/N
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lhartmann
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Delta Machines
I was thinking about building a delta printer inside a 300mm tube, using it both as structural support and heated build chamber.
PVC is really cheap and acrylic would look really nice. The second is 6x as expensive, but when diluted over the total cost of the printer it is probably worth it.
Anyways, I don' want to redesign the entire mechanical system. Which open-source delta would be a good s
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lhartmann
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Delta Machines
That is precisely the intention, all I need from the firmware is distance from "here" to endstop.
All the rest of the code should be on the PC-side, including an option to chose which way to home.
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lhartmann
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Developers
My primary interest are actually the jerk, acceleration and speed limits. These are way harder to set manually, and you will only know you are too high when it is too late.
Print volume is easy to setup manually, and yes it is a one time thing. However, since I already intended to measure the hard part why not do the easy one too? One less thing to do manually.
G29 and G31 are Z-probe specific.
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lhartmann
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Developers
My setup:
Absolute cheapest i3 clone, marlin fimware, melzi board. Work(ed) really well, albeit dead slow.
What I want to know:
Considering the firmware lost it's current position (power loss os missed steps) how do I measure the distance from the current position to home endstops?
Why do I need this:
I recently updated my computer and lost all the custom gcode I had set in Slic3r for my printe
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lhartmann
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Developers
IMHO you would be better off doing it backwards. Use the arduino to read gcode and parse it until you get easy units (motor steps and time steps), then feed these to the fpga and have it do motion control. Fairly easy to get 50MHz resolution on motion control this way, most arduino based printers run at 30~100kHZ.
Fpga are great with parallel realtime stuff, but quite hard to use (and overkill)
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lhartmann
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Developers
QuoteHubberthusRegarding the SD-card problem: (...) If you can harness the power of primary SPI, and do the timing from SW so you don't interfere with the SPI flash, then you're a master Jedi, and I'll bow down before you!
Challenge accepted! :-D
QuoteHubberthusWhoah, a gcode compression! Another fine topic. (...) With everybody creating their own format, it will soon be a huge mess.
Yup,
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lhartmann
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Developers
Slow SD interfaces are what we are trying to avoid, not because of the print time but because of the upload time. I just don't want to reach into my printer to take the SD out and pray my USB SD reader works, that's why I was looking into this. Your commenton SW SD made me realize that we could try SD over I2S (word-clock as SD-clock, 2 shifter outputs as CS and SDO, one shifter input as SDI), bu
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lhartmann
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Developers
QuotexebbmwThere is also another board NanoPi Neo that has a similar price.
When I saw the NanoPi Neo at aliexpress it was $30+, so I disregarded it. You link says $7 for base, +$2 for 512MB RAM, +$7 for wifi. Cheaper, but still way more than the Oranges.
Either way, checking this schematic I found that the I2S pins (pcm_*) are not all routed on the NanoPi Neo. Like the Orange Pi Zero it may st
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lhartmann
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Developers
QuoteHubberthus
@lhartmann - Weeell... It surely can work, I won't say it can't. But I'll rather stick to ESP32 when it comes to creating a firmware for the "family".
ESP32 is out already, both as ESP12-like and NodeMCU-like. For that price, though, we would be better off with an Orange Pi Lite. The advantages of the *Pi would be proper fast SD, filesystem, webserver, and we would be able to run
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lhartmann
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Developers
QuoteHubberthusIt's no use in starting to create an ESP firmware for ESP8266 when we have now the ESP32.
This "fun with ESP8266" is pretty good to reveal what problems I can run into with an actual ESP32-exclusive firmware, and what to use.
That is the point of an RTOS, we are not creating firmware for ESP8266, instead we are creating firmware based on FreeRTOS. That makes it incredibly easy to
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lhartmann
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Developers
My code uses semaphores, queues and threads instead of interrupts, buffers and ISR/main.
I am using freertos, take a look at it. That RTOS is amazing, you can have several tasks all running parallel and coded as of they were all alone in the mcu.
You also don't need an interrupt for the motors because the I2S buffers are already output at a fixed frequency. You can have 192kHz accurate sample r
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lhartmann
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Developers
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